multi-tenant implementierung

timetracker.Client/Components/Layout/MainLayout.razor

@@ -3,6 +3,7 @@
 @inject NavigationManager Nav
 @inject IUserNotificationService UserNotificationService
 @inject IJSRuntime JSRuntime
+@inject HttpClient Http
 @implements IDisposable
 @using System.Security.Claims
 
@@ -12,7 +13,7 @@
 <MudSnackbarProvider />
 
 <MudLayout>
-    <MudAppBar Elevation="0" Style="background: #0F172A; border-bottom: 1px solid rgba(255, 255, 255, 0.08);">
+    <MudAppBar Elevation="0" Style="background: color-mix(in srgb, var(--mud-palette-appbar-background) 85%, transparent); border-bottom: 1px solid rgba(255, 255, 255, 0.08); color: var(--mud-palette-appbar-text);">
         <AuthorizeView>
             <Authorized>
                 <MudIconButton Icon="@Icons.Material.Filled.Menu" Color="Color.Inherit" Edge="Edge.Start" OnClick="ToggleDrawer" Class="d-flex d-md-none mr-2" />
@@ -50,9 +51,74 @@
     private bool _drawerOpen = true;
     private bool _isDarkMode;
 
-    protected override void OnInitialized()
+    protected override async Task OnInitializedAsync()
     {
         UserNotificationService.OnUserDeleted += HandleUserDeleted;
+
+        try
+        {
+            var tenantInfo = await Http.GetFromJsonAsync<TenantInfo>("api/tenant/current");
+            if (tenantInfo?.IsTenant == true && !string.IsNullOrEmpty(tenantInfo.PrimaryColor))
+            {
+                var primaryColor = tenantInfo.PrimaryColor;
+                var secondaryColor = tenantInfo.SecondaryColor ?? tenantInfo.PrimaryColor;
+
+                _theme.PaletteLight.Primary = primaryColor;
+                _theme.PaletteLight.Secondary = secondaryColor;
+                _theme.PaletteDark.Primary = primaryColor;
+                _theme.PaletteDark.Secondary = secondaryColor;
+
+                // Dynamically apply background colors to navbar
+                _theme.PaletteLight.AppbarBackground = primaryColor;
+                _theme.PaletteLight.DrawerBackground = primaryColor;
+                _theme.PaletteDark.AppbarBackground = primaryColor;
+                _theme.PaletteDark.DrawerBackground = primaryColor;
+
+                // Adjust text/icon contrast based on background luminance
+                var isLight = IsLightColor(primaryColor);
+                var textCol = isLight ? "#0F172A" : "#FFFFFF";
+                var subTextCol = isLight ? "rgba(15, 23, 42, 0.70)" : "rgba(255, 255, 255, 0.70)";
+
+                _theme.PaletteLight.AppbarText = textCol;
+                _theme.PaletteLight.DrawerText = subTextCol;
+                _theme.PaletteLight.DrawerIcon = subTextCol;
+                _theme.PaletteLight.PrimaryContrastText = textCol;
+
+                _theme.PaletteDark.AppbarText = textCol;
+                _theme.PaletteDark.DrawerText = subTextCol;
+                _theme.PaletteDark.DrawerIcon = subTextCol;
+                _theme.PaletteDark.PrimaryContrastText = textCol;
+            }
+        }
+        catch
+        {
+            // Ignore background error
+        }
+    }
+
+    private bool IsLightColor(string hexColor)
+    {
+        if (string.IsNullOrEmpty(hexColor)) return false;
+        hexColor = hexColor.TrimStart('#');
+        if (hexColor.Length == 3)
+        {
+            hexColor = new string(new[] { hexColor[0], hexColor[0], hexColor[1], hexColor[1], hexColor[2], hexColor[2] });
+        }
+        if (hexColor.Length != 6) return false;
+
+        try
+        {
+            var r = Convert.ToInt32(hexColor.Substring(0, 2), 16);
+            var g = Convert.ToInt32(hexColor.Substring(2, 2), 16);
+            var b = Convert.ToInt32(hexColor.Substring(4, 2), 16);
+
+            var luminance = (0.299 * r + 0.587 * g + 0.114 * b) / 255.0;
+            return luminance > 0.6; // slightly conservative threshold for white text readability
+        }
+        catch
+        {
+            return false;
+        }
     }
 
     protected override async Task OnAfterRenderAsync(bool firstRender)

timetracker.Client/Components/Layout/MainLayout.razor.css

@@ -14,6 +14,7 @@
 }
 
 ::deep .modern-drawer {
+    background-color: var(--mud-palette-drawer-background) !important;
     border-right: 1px solid rgba(255, 255, 255, 0.08) !important;
     box-shadow: 4px 0 24px rgba(0, 0, 0, 0.1) !important;
     transition: width 0.25s cubic-bezier(0.4, 0, 0.2, 1) !important;
@@ -21,7 +22,7 @@
 
 /* Glassmorphism for the appbar */
 ::deep .mud-appbar {
-    background: rgba(15, 23, 42, 0.85) !important;
+    background: color-mix(in srgb, var(--mud-palette-appbar-background) 85%, transparent) !important;
     backdrop-filter: blur(12px) !important;
     -webkit-backdrop-filter: blur(12px) !important;
     border-bottom: 1px solid rgba(255, 255, 255, 0.08) !important;

timetracker.Client/Components/Layout/NavMenu.razor

@@ -1,4 +1,5 @@
 @inject IJSRuntime JSRuntime
+@inject HttpClient Http
 <div class="nav-container onboarding-nav-menu">
     @* --- Brand / Logo Section --- *@
     <div class="nav-header">
@@ -37,6 +38,11 @@
                         <span class="admin-divider-text">Admin</span>
                         <hr class="admin-divider-line" />
                     </div>
+                    <MudTooltip Text="Firmen verwalten (SaaS)" Placement="Placement.Right">
+                        <MudNavLink Href="superadmin" Icon="@Icons.Material.Filled.Business" Class="custom-nav-link admin-link">
+                            Firmen verwalten
+                        </MudNavLink>
+                    </MudTooltip>
                     <MudTooltip Text="Benutzerverwaltung" Placement="Placement.Right">
                         <MudNavLink Href="admin/users" Icon="@Icons.Material.Filled.AdminPanelSettings" Class="custom-nav-link admin-link">
                             Benutzerverwaltung
@@ -61,7 +67,7 @@
                         </div>
                         <div class="user-info">
                             <span class="user-name">@context.User.Identity?.Name</span>
-                            <span class="user-status">Online</span>
+                            <span class="user-status">@_companyName</span>
                         </div>
                     </div>
                 </NavLink>
@@ -93,6 +99,23 @@
     [Parameter] public EventCallback OnToggleDrawer { get; set; }
 
     private bool _showVersionBadge;
+    private string _companyName = "Hauptdomain";
+
+    protected override async Task OnInitializedAsync()
+    {
+        try
+        {
+            var tenantInfo = await Http.GetFromJsonAsync<TenantInfo>("api/tenant/current");
+            if (tenantInfo?.IsTenant == true && !string.IsNullOrEmpty(tenantInfo.Name))
+            {
+                _companyName = tenantInfo.Name;
+            }
+        }
+        catch
+        {
+            // Ignore background error
+        }
+    }
 
     protected override async Task OnAfterRenderAsync(bool firstRender)
     {

timetracker.Client/Components/Layout/NavMenu.razor.css

@@ -44,7 +44,7 @@
 }
 
 ::deep .logo-icon {
-    color: #0EA5E9 !important; /* Sky 500 */
+    color: var(--mud-palette-secondary) !important;
     font-size: 1.6rem !important;
     transition: opacity 0.2s ease;
 }
@@ -52,7 +52,7 @@
 .brand-text {
     font-size: 1.1rem;
     font-weight: 800;
-    color: #FFFFFF;
+    color: var(--mud-palette-appbar-text);
     letter-spacing: 0.5px;
     white-space: nowrap;
     opacity: 1;
@@ -104,7 +104,7 @@
 ::deep .custom-nav-link,
 ::deep .custom-nav-link .mud-nav-link-text,
 ::deep .custom-nav-link .mud-nav-link-icon-default {
-    color: #94A3B8 !important; /* Slate 400 */
+    color: var(--mud-palette-drawer-text) !important;
 }
 
 /* NavLink hover */
@@ -115,15 +115,15 @@
 ::deep .custom-nav-link:hover,
 ::deep .custom-nav-link:hover .mud-nav-link-text,
 ::deep .custom-nav-link:hover .mud-nav-link-icon-default {
-    color: #F8FAFC !important; /* Slate 50 */
+    color: var(--mud-palette-appbar-text) !important;
 }
 
 /* NavLink active state (Fixes active color contrast issue) */
 ::deep .custom-nav-link.active,
 ::deep .custom-nav-link .active {
-    background: linear-gradient(90deg, rgba(14, 165, 233, 0.15) 0%, rgba(14, 165, 233, 0.04) 100%) !important;
+    background: linear-gradient(90deg, color-mix(in srgb, var(--mud-palette-secondary) 15%, transparent) 0%, color-mix(in srgb, var(--mud-palette-secondary) 4%, transparent) 100%) !important;
     font-weight: 600 !important;
-    box-shadow: inset 3px 0 0 #0EA5E9 !important;
+    box-shadow: inset 3px 0 0 var(--mud-palette-secondary) !important;
 }
 
 ::deep .custom-nav-link.active,
@@ -132,7 +132,7 @@
 ::deep .custom-nav-link .active .mud-nav-link-text,
 ::deep .custom-nav-link.active .mud-nav-link-icon-default,
 ::deep .custom-nav-link .active .mud-nav-link-icon-default {
-    color: #0EA5E9 !important; /* Sky 500 */
+    color: var(--mud-palette-secondary) !important;
 }
 
 /* Admin link color overrides & active state */
@@ -208,7 +208,7 @@
 ::deep .user-avatar {
     width: 36px !important;
     height: 36px !important;
-    background: linear-gradient(135deg, #0EA5E9 0%, #0284C7 100%) !important;
+    background: linear-gradient(135deg, var(--mud-palette-secondary) 0%, var(--mud-palette-secondary-darken) 100%) !important;
     color: #FFFFFF !important;
     font-weight: 700 !important;
     font-size: 0.875rem !important;
@@ -222,7 +222,7 @@
     width: 10px;
     height: 10px;
     background-color: #10B981; /* Emerald 500 */
-    border: 2px solid #0F172A;
+    border: 2px solid var(--mud-palette-drawer-background);
     border-radius: 50%;
 }
 
@@ -236,7 +236,7 @@
 .user-name {
     font-size: 0.85rem;
     font-weight: 600;
-    color: #FFFFFF;
+    color: var(--mud-palette-appbar-text);
     white-space: nowrap;
     text-overflow: ellipsis;
     overflow: hidden;

timetracker.Client/Components/Pages/AdminUsers.razor

@@ -1,10 +1,14 @@
 @page "/admin/users"
 @rendermode InteractiveWebAssembly
 @attribute [Authorize(Policy = "AdminOnly")]
+@using System.Net.Http.Json
+@using System.Security.Claims
 @inject IAuthService AuthService
 @inject ISnackbar Snackbar
 @inject AuthenticationStateProvider AuthStateProvider
 @inject IUserNotificationService UserNotificationService
+@inject HttpClient Http
+@inject IDialogService DialogService
 @implements IDisposable
 
 <PageTitle>Benutzerverwaltung – Timetracker</PageTitle>
@@ -42,6 +46,7 @@ else
                     <HeaderContent>
                         <MudTh><MudTableSortLabel SortBy="new Func<User, object>(u => u.Id)">ID</MudTableSortLabel></MudTh>
                         <MudTh><MudTableSortLabel SortBy="new Func<User, object>(u => u.Username)" InitialDirection="SortDirection.Ascending">Benutzername</MudTableSortLabel></MudTh>
+                        <MudTh>Firma / Mandant</MudTh>
                         <MudTh Style="text-align:right">Aktionen</MudTh>
                     </HeaderContent>
                     <RowTemplate>
@@ -74,6 +79,34 @@ else
                                 </MudStack>
                             }
                         </MudTd>
+                        <MudTd>
+                            @if (_editUserId == context.Id)
+                            {
+                                <MudSelect @bind-Value="_editTenantId" Margin="Margin.Dense" T="int?" Label="Firma zuweisen" Variant="Variant.Outlined" Style="max-width:250px">
+                                    <MudSelectItem T="int?" Value="@((int?)null)">Hauptdomain (System/Global)</MudSelectItem>
+                                    @foreach (var tenant in _tenants)
+                                    {
+                                        <MudSelectItem T="int?" Value="@((int?)tenant.Id)">@tenant.Name (@tenant.Subdomain)</MudSelectItem>
+                                    }
+                                </MudSelect>
+                            }
+                            else
+                            {
+                                @if (context.TenantId.HasValue)
+                                {
+                                    var t = _tenants.FirstOrDefault(x => x.Id == context.TenantId.Value);
+                                    <MudChip T="string" Color="Color.Primary" Variant="Variant.Outlined" Size="Size.Small">
+                                        @(t?.Name ?? $"Firma #{context.TenantId}")
+                                    </MudChip>
+                                }
+                                else
+                                {
+                                    <MudChip T="string" Color="Color.Default" Variant="Variant.Text" Size="Size.Small">
+                                        Hauptdomain (SuperUser)
+                                    </MudChip>
+                                }
+                            }
+                        </MudTd>
                         <MudTd Style="text-align:right">
                             @if (_editUserId == context.Id)
                             {
@@ -92,6 +125,12 @@ else
                                                Color="Color.Primary"
                                                Size="Size.Small"
                                                OnClick="@(() => StartEdit(context))" />
+                                <MudTooltip Text="Passwort zurücksetzen">
+                                    <MudIconButton Icon="@Icons.Material.Filled.LockReset"
+                                                   Color="Color.Warning"
+                                                   Size="Size.Small"
+                                                   OnClick="@(() => OpenResetPasswordDialog(context))" />
+                                </MudTooltip>
                                 @if (context.Username != "marc")
                                 {
                                     <MudIconButton Icon="@Icons.Material.Filled.DeleteOutline"
@@ -114,9 +153,11 @@ else
 
 @code {
     private List<User> _users = [];
+    private List<TenantStats> _tenants = [];
     private bool _loading = true;
     private int? _editUserId;
     private string _editUsername = "";
+    private int? _editTenantId;
 
     protected override async Task OnInitializedAsync()
     {
@@ -125,13 +166,31 @@ else
         if (claim == null) return;
 
         UserNotificationService.OnUsersChanged += RefreshUsers;
-        _users = await AuthService.GetAllUsersAsync();
+        
+        try
+        {
+            _users = await AuthService.GetAllUsersAsync();
+            _tenants = await Http.GetFromJsonAsync<List<TenantStats>>("api/superadmin/tenants") ?? [];
+        }
+        catch (Exception ex)
+        {
+            Snackbar.Add($"Fehler beim Laden der Daten: {ex.Message}", Severity.Error);
+        }
+        
         _loading = false;
     }
 
     private async Task RefreshUsers()
     {
         _users = await AuthService.GetAllUsersAsync();
+        try
+        {
+            _tenants = await Http.GetFromJsonAsync<List<TenantStats>>("api/superadmin/tenants") ?? [];
+        }
+        catch
+        {
+            // Ignore background refresh errors
+        }
         await InvokeAsync(StateHasChanged);
     }
 
@@ -144,27 +203,49 @@ else
     {
         _editUserId = user.Id;
         _editUsername = user.Username;
+        _editTenantId = user.TenantId;
     }
 
     private void CancelEdit()
     {
         _editUserId = null;
         _editUsername = "";
+        _editTenantId = null;
     }
 
     private async Task SaveRename(User user)
     {
         var trimmed = _editUsername.Trim();
-        var error = await AuthService.RenameUserAsync(user.Id, trimmed);
+        
-        if (error != null)
+        // 1. Rename if username changed
+        if (trimmed != user.Username)
         {
-            Snackbar.Add(error, Severity.Error);
+            var error = await AuthService.RenameUserAsync(user.Id, trimmed);
-            return;
+            if (error != null)
+            {
+                Snackbar.Add(error, Severity.Error);
+                return;
+            }
+            user.Username = trimmed;
         }
-        user.Username = trimmed;
+
+        // 2. Move to tenant if tenant ID changed
+        if (_editTenantId != user.TenantId)
+        {
+            var error = await AuthService.AssignTenantAsync(user.Id, _editTenantId);
+            if (error != null)
+            {
+                Snackbar.Add(error, Severity.Error);
+                return;
+            }
+            user.TenantId = _editTenantId;
+        }
+
         _editUserId = null;
         _editUsername = "";
-        Snackbar.Add($"Benutzer umbenannt zu \"{trimmed}\".", Severity.Success);
+        _editTenantId = null;
+        
+        Snackbar.Add("Benutzerdaten erfolgreich aktualisiert.", Severity.Success);
     }
 
     private async Task DeleteUser(User user)
@@ -173,4 +254,29 @@ else
         _users.Remove(user);
         Snackbar.Add($"Benutzer \"{user.Username}\" gelöscht.", Severity.Info);
     }
+
+    private async Task OpenResetPasswordDialog(User user)
+    {
+        var parameters = new DialogParameters<ResetPasswordDialog>
+        {
+            { x => x.Username, user.Username }
+        };
+
+        var options = new DialogOptions { CloseButton = true, MaxWidth = MaxWidth.Small, FullWidth = true };
+        var dialog = await DialogService.ShowAsync<ResetPasswordDialog>("Passwort zurücksetzen", parameters, options);
+        var result = await dialog.Result;
+
+        if (result != null && !result.Canceled && result.Data is string newPassword)
+        {
+            var error = await AuthService.ResetPasswordAsync(user.Id, newPassword);
+            if (error != null)
+            {
+                Snackbar.Add(error, Severity.Error);
+            }
+            else
+            {
+                Snackbar.Add($"Passwort für {user.Username} wurde erfolgreich zurückgesetzt.", Severity.Success);
+            }
+        }
+    }
 }

timetracker.Client/Components/Pages/Agb.razor

@@ -8,12 +8,12 @@
     <MudStack Spacing="4">
         
         @* ── Header ── *@
-        <MudPaper Elevation="4" Class="pa-5 rounded-xl" Style="background: #1E293B; color: white;">
+        <MudPaper Elevation="4" Class="pa-5 rounded-xl mud-theme-primary">
             <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="3">
-                <MudIcon Icon="@Icons.Material.Filled.Gavel" Style="color: white; font-size: 2.2rem;" />
+                <MudIcon Icon="@Icons.Material.Filled.Gavel" Style="color: var(--mud-palette-primary-text); font-size: 2.2rem;" />
                 <MudStack Spacing="0">
-                    <MudText Typo="Typo.h5" Style="color: white; font-weight: 700;">Allgemeine Geschäftsbedingungen (AGB)</MudText>
+                    <MudText Typo="Typo.h5" Style="color: var(--mud-palette-primary-text); font-weight: 700;">Allgemeine Geschäftsbedingungen (AGB)</MudText>
-                    <MudText Typo="Typo.caption" Style="color: rgba(255,255,255,0.72);">
+                    <MudText Typo="Typo.caption" Style="color: var(--mud-palette-primary-text); opacity: 0.72;">
                         Rechtlich absolut unverbindliches Kauderwelsch und Flachwitze
                     </MudText>
                 </MudStack>

timetracker.Client/Components/Pages/Changelog.razor

@@ -8,13 +8,12 @@
 <MudStack Spacing="4">
 
     @* ── Header ── *@
-    <MudPaper Elevation="4" Class="pa-5 rounded-xl"
+    <MudPaper Elevation="4" Class="pa-5 rounded-xl mud-theme-primary">
-              Style="background: #1E293B; color:white;">
         <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="3">
-            <MudIcon Icon="@Icons.Material.Filled.NewReleases" Style="color:white; font-size:2rem" />
+            <MudIcon Icon="@Icons.Material.Filled.NewReleases" Style="color: var(--mud-palette-primary-text); font-size:2rem" />
             <MudStack Spacing="0">
-                <MudText Typo="Typo.h5" Style="color:white; font-weight:700">Changelog</MudText>
+                <MudText Typo="Typo.h5" Style="color: var(--mud-palette-primary-text); font-weight:700">Changelog</MudText>
-                <MudText Typo="Typo.caption" Style="color:rgba(255,255,255,0.72)">Versionshistorie &amp; Änderungen</MudText>
+                <MudText Typo="Typo.caption" Style="color: var(--mud-palette-primary-text); opacity: 0.72">Versionshistorie &amp; Änderungen</MudText>
             </MudStack>
         </MudStack>
     </MudPaper>

timetracker.Client/Components/Pages/Home.razor

@@ -21,29 +21,28 @@ else
     <MudStack Spacing="3">
 
         @* ── Wochen-Header ── *@
-        <MudPaper Elevation="4" Class="pa-5 rounded-xl onboarding-week-header"
+        <MudPaper Elevation="4" Class="pa-5 rounded-xl onboarding-week-header mud-theme-primary">
-                  Style="background: #1E293B; color: white;">
             <MudStack Row="true" AlignItems="AlignItems.Center" Justify="Justify.SpaceBetween">
                 <MudIconButton Icon="@Icons.Material.Filled.ChevronLeft"
-                               Style="color:white" Size="Size.Large" OnClick="PrevWeek" />
+                               Style="color: var(--mud-palette-primary-text)" Size="Size.Large" OnClick="PrevWeek" />
                 <MudStack Spacing="0" AlignItems="AlignItems.Center">
-                    <MudText Typo="Typo.h5" Style="color:white; font-weight:700; letter-spacing:0.5px">
+                    <MudText Typo="Typo.h5" Style="color: var(--mud-palette-primary-text); font-weight:700; letter-spacing:0.5px">
                         @_weekLabel
                     </MudText>
-                    <MudText Typo="Typo.caption" Style="color:rgba(255,255,255,0.72)">
+                    <MudText Typo="Typo.caption" Style="color: var(--mud-palette-primary-text); opacity: 0.72">
                         @_weekSubLabel
                     </MudText>
                 </MudStack>
                 <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="0">
                     @if (!IsCurrentWeek)
                     {
-                        <MudButton Variant="Variant.Text" Style="color:white"
+                        <MudButton Variant="Variant.Text" Style="color: var(--mud-palette-primary-text)"
                                    OnClick="GoToCurrentWeek" Size="Size.Small">
                             Heute
                         </MudButton>
                     }
                     <MudIconButton Icon="@Icons.Material.Filled.ChevronRight"
-                                   Style="color:white" Size="Size.Large" OnClick="NextWeek" />
+                                   Style="color: var(--mud-palette-primary-text)" Size="Size.Large" OnClick="NextWeek" />
                 </MudStack>
             </MudStack>
         </MudPaper>
@@ -316,34 +315,34 @@ else
 
         @* ── Wochensumme ── *@
         <MudPaper Elevation="4" Class="pa-5 rounded-xl onboarding-week-summary"
-                  Style="background: #0F172A; color:white;">
+                  Style="background: var(--mud-palette-primary-darken); color: var(--mud-palette-primary-text);">
             <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="2" Class="mb-4">
-                <MudIcon Icon="@Icons.Material.Filled.Summarize" Style="color:rgba(255,255,255,0.8)" />
+                <MudIcon Icon="@Icons.Material.Filled.Summarize" Style="color: var(--mud-palette-primary-text); opacity: 0.8" />
-                <MudText Typo="Typo.h6" Style="color:white; font-weight:600">Wochensumme</MudText>
+                <MudText Typo="Typo.h6" Style="color: var(--mud-palette-primary-text); font-weight:600">Wochensumme</MudText>
             </MudStack>
             <MudGrid Spacing="3">
                 <MudItem xs="6" sm="3">
                     <MudStack Spacing="0">
-                        <MudText Typo="Typo.overline" Style="color:rgba(255,255,255,0.6)">Brutto</MudText>
+                        <MudText Typo="Typo.overline" Style="color: var(--mud-palette-primary-text); opacity: 0.6">Brutto</MudText>
-                        <MudText Typo="Typo.h5" Style="color:white">@FormatTs(WeekGross)</MudText>
+                        <MudText Typo="Typo.h5" Style="color: var(--mud-palette-primary-text)">@FormatTs(WeekGross)</MudText>
                     </MudStack>
                 </MudItem>
                 <MudItem xs="6" sm="3">
                     <MudStack Spacing="0">
-                        <MudText Typo="Typo.overline" Style="color:rgba(255,255,255,0.6)">Pausen</MudText>
+                        <MudText Typo="Typo.overline" Style="color: var(--mud-palette-primary-text); opacity: 0.6">Pausen</MudText>
-                        <MudText Typo="Typo.h5" Style="color:white">@FormatTs(WeekBreaks)</MudText>
+                        <MudText Typo="Typo.h5" Style="color: var(--mud-palette-primary-text)">@FormatTs(WeekBreaks)</MudText>
                     </MudStack>
                 </MudItem>
                 <MudItem xs="6" sm="3">
                     <MudStack Spacing="0">
-                        <MudText Typo="Typo.overline" Style="color:rgba(255,255,255,0.6)">Netto</MudText>
+                        <MudText Typo="Typo.overline" Style="color: var(--mud-palette-primary-text); opacity: 0.6">Netto</MudText>
-                        <MudText Typo="Typo.h5" Style="color:#90CAF9; font-weight:700">@FormatTs(WeekNet)</MudText>
+                        <MudText Typo="Typo.h5" Color="Color.Secondary" Style="font-weight:700">@FormatTs(WeekNet)</MudText>
                     </MudStack>
                 </MudItem>
                 <MudItem xs="6" sm="3">
                     <MudStack Spacing="0">
-                        <MudText Typo="Typo.overline" Style="color:rgba(255,255,255,0.6)">Gleitzeit</MudText>
+                        <MudText Typo="Typo.overline" Style="color: var(--mud-palette-primary-text); opacity: 0.6">Gleitzeit</MudText>
-                        <MudText Typo="Typo.h5" Style="@($"color:{(WeekOvertime >= TimeSpan.Zero ? "#A5D6A7" : "#FFCC80")}; font-weight:700")">
+                        <MudText Typo="Typo.h5" Color="@(WeekOvertime >= TimeSpan.Zero ? Color.Success : Color.Warning)" Style="font-weight:700">
                             @FormatTs(WeekOvertime, sign: true)
                         </MudText>
                     </MudStack>

timetracker.Client/Components/Pages/Login.razor

@@ -1,149 +1,312 @@
 @page "/login"
 @rendermode InteractiveWebAssembly
 @attribute [AllowAnonymous]
+@using System.Net.Http.Json
 @inject IAuthService AuthService
 @inject NavigationManager Nav
 @inject IJSRuntime JSRuntime
+@inject HttpClient Http
 
-<PageTitle>Anmelden – Timetracker</PageTitle>
+<PageTitle>@GetPageTitle()</PageTitle>
 
-<MudContainer MaxWidth="MaxWidth.Small" Class="mt-16">
+@if (_tenantInfo == null)
-    <MudStack AlignItems="AlignItems.Center" Spacing="4">
+{
-
+    @* Loading indicator while resolving Tenant *@
-        @* ── Logo / Header ── *@
+    <MudContainer MaxWidth="MaxWidth.Small" Class="mt-16 text-center">
-        <MudStack AlignItems="AlignItems.Center" Spacing="1">
+        <MudProgressCircular Color="Color.Primary" Indeterminate="true" Size="Size.Large" />
-            <MudIcon Icon="@Icons.Material.Filled.AccessTime"
+        <MudText Class="mt-4" Color="Color.Secondary">Lade Timetracker…</MudText>
-                     Style="font-size:4rem; color:#0EA5E9" />
+    </MudContainer>
-            <MudText Typo="Typo.h4" Style="font-weight:700; color:#0EA5E9">Timetracker</MudText>
+}
-        </MudStack>
+else if (_tenantInfo.IsTenant && !_tenantInfo.IsApproved)
-
+{
-        <MudPaper Elevation="4" Class="pa-6 rounded-xl" Style="width:100%">
+    @* Pending Approval Screen *@
-            @* ── Tab Navigation ── *@
+    <MudContainer MaxWidth="MaxWidth.Small" Class="mt-16">
-            <MudStack Row="true" Justify="Justify.Center" Class="mb-4">
+        <MudStack AlignItems="AlignItems.Center" Spacing="4">
-                <MudButton OnClick="@(() => SetTab(0))"
+            <MudStack AlignItems="AlignItems.Center" Spacing="1">
-                           Variant="@(_activeTab == 0 ? Variant.Filled : Variant.Text)"
+                <MudIcon Icon="@Icons.Material.Filled.AccessTime" Style="font-size:4rem; color:#EAB308" />
-                           Color="Color.Primary"
+                <MudText Typo="Typo.h4" Style="font-weight:700; color:#EAB308">Timetracker</MudText>
-                           Style="min-width: 120px; border-radius: 20px;">
-                    Anmelden
-                </MudButton>
-                <MudButton OnClick="@(() => SetTab(1))"
-                           Variant="@(_activeTab == 1 ? Variant.Filled : Variant.Text)"
-                           Color="Color.Primary"
-                           Style="min-width: 120px; border-radius: 20px;">
-                    Registrieren
-                </MudButton>
             </MudStack>
 
-            <MudDivider Class="mb-6" />
+            <MudPaper Elevation="4" Class="pa-8 rounded-xl text-center" Style="width:100%; border-top: 4px solid var(--mud-palette-warning);">
+                <MudIcon Icon="@Icons.Material.Filled.HourglassEmpty" 
+                         Style="font-size: 5rem; animation: pulse 2s infinite;" 
+                         Color="Color.Warning" 
+                         Class="mb-4" />
+                <MudText Typo="Typo.h5" Style="font-weight: 700;" Class="mb-2">Freischaltung ausstehend</MudText>
+                <MudText Typo="Typo.body1" Color="Color.Secondary" Class="mb-6">
+                    Die Firma <strong>@_tenantInfo.Name</strong> wurde erfolgreich registriert. 
+                    Der Zugang wird derzeit von unserem SuperAdmin geprüft und in Kürze freigeschaltet.
+                </MudText>
+                <MudDivider Class="my-4" />
+                <MudText Typo="Typo.caption" Color="Color.Secondary">
+                    Bitte laden Sie diese Seite in Kürze neu, sobald Ihr Account freigegeben wurde.
+                </MudText>
+            </MudPaper>
+        </MudStack>
+    </MudContainer>
 
-            @if (_activeTab == 0)
+    <style>
-            {
+        @@keyframes pulse {
-                @* ── Login Form ── *@
+            0% { opacity: 0.6; transform: scale(1); }
-                <MudStack Spacing="3">
+            50% { opacity: 1; transform: scale(1.05); }
-                    @if (_error != null)
+            100% { opacity: 0.6; transform: scale(1); }
-                    {
+        }
-                        <MudAlert Severity="Severity.Error" Dense="true">@_error</MudAlert>
+    </style>
-                    }
+}
-                    <EditForm Model="@_loginModel" OnValidSubmit="HandleLogin">
+else
-                        <MudStack Spacing="3">
+{
-                            <MudTextField T="string"
+    @* Main login/registration container *@
-                                          Label="Benutzername"
+    <MudContainer MaxWidth="MaxWidth.Small" Class="mt-16">
-                                          Variant="Variant.Outlined"
+        <MudStack AlignItems="AlignItems.Center" Spacing="4">
-                                          Adornment="Adornment.Start"
-                                          AdornmentIcon="@Icons.Material.Filled.Person"
-                                          @bind-Value="_loginModel.Username"
-                                          Required="true"
-                                          AutoFocus="true" />
-                            <MudTextField T="string"
-                                          Label="Passwort"
-                                          Variant="Variant.Outlined"
-                                          Adornment="Adornment.Start"
-                                          AdornmentIcon="@Icons.Material.Filled.Lock"
-                                          InputType="InputType.Password"
-                                          @bind-Value="_loginModel.Password"
-                                          Required="true" />
-                            <MudButton ButtonType="ButtonType.Submit"
-                                       Variant="Variant.Filled"
-                                       Color="Color.Primary"
-                                       FullWidth="true"
-                                       Size="Size.Large"
-                                       StartIcon="@Icons.Material.Filled.Login"
-                                       Class="mt-2"
-                                       Disabled="_loading">
-                                @if (_loading)
-                                {
-                                    <MudProgressCircular Size="Size.Small" Indeterminate="true" Class="mr-2" />
-                                }
-                                Anmelden
-                            </MudButton>
-                        </MudStack>
-                    </EditForm>
-                </MudStack>
-            }
-            else
-            {
-                @* ── Register Form ── *@
-                <MudStack Spacing="3">
-                    @if (_error != null)
-                    {
-                        <MudAlert Severity="Severity.Error" Dense="true">@_error</MudAlert>
-                    }
-                    <EditForm Model="@_registerModel" OnValidSubmit="HandleRegister">
-                        <MudStack Spacing="3">
-                            <MudTextField T="string"
-                                          Label="Benutzername"
-                                          Variant="Variant.Outlined"
-                                          Adornment="Adornment.Start"
-                                          AdornmentIcon="@Icons.Material.Filled.Person"
-                                          @bind-Value="_registerModel.Username"
-                                          Required="true"
-                                          HelperText="Mindestens 3 Zeichen" />
-                            <MudTextField T="string"
-                                          Label="Passwort"
-                                          Variant="Variant.Outlined"
-                                          Adornment="Adornment.Start"
-                                          AdornmentIcon="@Icons.Material.Filled.Lock"
-                                          InputType="InputType.Password"
-                                          @bind-Value="_registerModel.Password"
-                                          Required="true"
-                                          HelperText="Mindestens 6 Zeichen" />
-                            <input type="text" style="display: none;" tabindex="-1" autocomplete="off" @bind="_honeypot" />
-                            
-                            <MudCheckBox @bind-Value="_acceptAgb" Color="Color.Secondary" Class="mt-1">
-                                <MudText Typo="Typo.body2">Ich akzeptiere die <a href="/agb" target="_blank" style="color: var(--mud-palette-secondary); text-decoration: underline; font-weight: 600;">AGB</a>.</MudText>
-                            </MudCheckBox>
 
-                            <MudButton ButtonType="ButtonType.Submit"
+            @* ── Logo / Header ── *@
-                                       Variant="Variant.Filled"
+            <MudStack AlignItems="AlignItems.Center" Spacing="1">
-                                       Color="Color.Secondary"
+                <MudIcon Icon="@Icons.Material.Filled.AccessTime"
-                                       FullWidth="true"
+                         Style="font-size:4rem; color:#0EA5E9" />
-                                       Size="Size.Large"
+                <MudText Typo="Typo.h4" Style="font-weight:700; color:#0EA5E9">
-                                       StartIcon="@Icons.Material.Filled.PersonAdd"
+                    @(_tenantInfo.IsTenant ? _tenantInfo.Name : "Timetracker SaaS")
-                                       Class="mt-2"
+                </MudText>
-                                       Disabled="_loading || !_acceptAgb">
+                @if (!_tenantInfo.IsTenant)
-                                @if (_loading)
+                {
-                                {
+                    <MudText Typo="Typo.caption" Color="Color.Secondary">Zentrales Portal</MudText>
-                                    <MudProgressCircular Size="Size.Small" Indeterminate="true" Class="mr-2" />
+                }
-                                }
+            </MudStack>
-                                Konto erstellen
+
-                            </MudButton>
+            <MudPaper Elevation="4" Class="pa-6 rounded-xl" Style="width:100%">
+                @if (_firmRegisteredSuccessfully)
+                {
+                    @* Success feedback after firm registration *@
+                    <MudStack Spacing="4" AlignItems="AlignItems.Center" Class="text-center pa-4">
+                        <MudIcon Icon="@Icons.Material.Filled.CheckCircle" Color="Color.Success" Style="font-size:5rem;" />
+                        <MudText Typo="Typo.h5" Style="font-weight:700;">Registrierung erfolgreich!</MudText>
+                        <MudText Typo="Typo.body1" Color="Color.Secondary">
+                            Ihre Firma <strong>@_firmModel.CompanyName</strong> wurde erfolgreich registriert.
+                        </MudText>
+                        <MudAlert Severity="Severity.Info" Class="rounded-lg">
+                            Ihr Zugang muss nun durch den SuperAdmin freigegeben werden. Danach können Sie sich unter Ihrer Subdomain anmelden:
+                            <br /><br />
+                            <strong>@GetTenantUrl()</strong>
+                        </MudAlert>
+                        <MudButton Variant="Variant.Filled" Color="Color.Primary" Class="mt-4" OnClick="ResetRegistrationFlow">
+                            Zurück zum Login
+                        </MudButton>
+                    </MudStack>
+                }
+                else
+                {
+                    @* ── Tab Navigation ── *@
+                    <MudStack Row="true" Justify="Justify.Center" Class="mb-4">
+                        <MudButton OnClick="@(() => SetTab(0))"
+                                   Variant="@(_activeTab == 0 ? Variant.Filled : Variant.Text)"
+                                   Color="Color.Primary"
+                                   Style="min-width: 120px; border-radius: 20px;">
+                            Anmelden
+                        </MudButton>
+                        <MudButton OnClick="@(() => SetTab(1))"
+                                   Variant="@(_activeTab == 1 ? Variant.Filled : Variant.Text)"
+                                   Color="Color.Primary"
+                                   Style="min-width: 120px; border-radius: 20px;">
+                            @(_tenantInfo.IsTenant ? "Registrieren" : "Firma registrieren")
+                        </MudButton>
+                    </MudStack>
+
+                    <MudDivider Class="mb-6" />
+
+                    @if (_activeTab == 0)
+                    {
+                        @* ── Login Form ── *@
+                        <MudStack Spacing="3">
+                            @if (_error != null)
+                            {
+                                <MudAlert Severity="Severity.Error" Dense="true">@_error</MudAlert>
+                            }
+                            <EditForm Model="@_loginModel" OnValidSubmit="HandleLogin">
+                                <MudStack Spacing="3">
+                                    <MudTextField T="string"
+                                                  Label="Benutzername"
+                                                  Variant="Variant.Outlined"
+                                                  Adornment="Adornment.Start"
+                                                  AdornmentIcon="@Icons.Material.Filled.Person"
+                                                  @bind-Value="_loginModel.Username"
+                                                  Required="true"
+                                                  AutoFocus="true" />
+                                    <MudTextField T="string"
+                                                  Label="Passwort"
+                                                  Variant="Variant.Outlined"
+                                                  Adornment="Adornment.Start"
+                                                  AdornmentIcon="@Icons.Material.Filled.Lock"
+                                                  InputType="InputType.Password"
+                                                  @bind-Value="_loginModel.Password"
+                                                  Required="true" />
+                                    <MudButton ButtonType="ButtonType.Submit"
+                                               Variant="Variant.Filled"
+                                               Color="Color.Primary"
+                                               FullWidth="true"
+                                               Size="Size.Large"
+                                               StartIcon="@Icons.Material.Filled.Login"
+                                               Class="mt-2"
+                                               Disabled="_loading">
+                                        @if (_loading)
+                                        {
+                                            <MudProgressCircular Size="Size.Small" Indeterminate="true" Class="mr-2" />
+                                        }
+                                        Anmelden
+                                    </MudButton>
+                                </MudStack>
+                            </EditForm>
                         </MudStack>
-                    </EditForm>
+                    }
-                </MudStack>
+                    else
-            }
+                    {
-        </MudPaper>
+                        @if (_tenantInfo.IsTenant)
-    </MudStack>
+                        {
-</MudContainer>
+                            @* ── Employee Register Form ── *@
+                            <MudStack Spacing="3">
+                                @if (_error != null)
+                                {
+                                    <MudAlert Severity="Severity.Error" Dense="true">@_error</MudAlert>
+                                }
+                                <EditForm Model="@_registerModel" OnValidSubmit="HandleRegister">
+                                    <MudStack Spacing="3">
+                                        <MudTextField T="string"
+                                                      Label="Benutzername"
+                                                      Variant="Variant.Outlined"
+                                                      Adornment="Adornment.Start"
+                                                      AdornmentIcon="@Icons.Material.Filled.Person"
+                                                      @bind-Value="_registerModel.Username"
+                                                      Required="true"
+                                                      HelperText="Mindestens 3 Zeichen" />
+                                        <MudTextField T="string"
+                                                      Label="Passwort"
+                                                      Variant="Variant.Outlined"
+                                                      Adornment="Adornment.Start"
+                                                      AdornmentIcon="@Icons.Material.Filled.Lock"
+                                                      InputType="InputType.Password"
+                                                      @bind-Value="_registerModel.Password"
+                                                      Required="true"
+                                                      HelperText="Mindestens 6 Zeichen" />
+                                        <input type="text" style="display: none;" tabindex="-1" autocomplete="off" @bind="_honeypot" />
+                                        
+                                        <MudCheckBox @bind-Value="_acceptAgb" Color="Color.Secondary" Class="mt-1">
+                                            <MudText Typo="Typo.body2">Ich akzeptiere die <a href="/agb" target="_blank" style="color: var(--mud-palette-secondary); text-decoration: underline; font-weight: 600;">AGB</a>.</MudText>
+                                        </MudCheckBox>
+
+                                        <MudButton ButtonType="ButtonType.Submit"
+                                                   Variant="Variant.Filled"
+                                                   Color="Color.Secondary"
+                                                   FullWidth="true"
+                                                   Size="Size.Large"
+                                                   StartIcon="@Icons.Material.Filled.PersonAdd"
+                                                   Class="mt-2"
+                                                   Disabled="_loading || !_acceptAgb">
+                                            @if (_loading)
+                                            {
+                                                <MudProgressCircular Size="Size.Small" Indeterminate="true" Class="mr-2" />
+                                            }
+                                            Konto erstellen
+                                        </MudButton>
+                                    </MudStack>
+                                </EditForm>
+                            </MudStack>
+                        }
+                        else
+                        {
+                            @* ── Firm Register Form ── *@
+                            <MudStack Spacing="3">
+                                @if (_error != null)
+                                {
+                                    <MudAlert Severity="Severity.Error" Dense="true">@_error</MudAlert>
+                                }
+                                <EditForm Model="@_firmModel" OnValidSubmit="HandleRegisterFirm">
+                                    <DataAnnotationsValidator />
+                                    <MudStack Spacing="3">
+                                        <MudTextField T="string"
+                                                      Label="Firmenname (z.B. Acme GmbH)"
+                                                      Variant="Variant.Outlined"
+                                                      @bind-Value="_firmModel.CompanyName"
+                                                      Required="true" />
+                                        
+                                        <MudTextField T="string"
+                                                      Label="Subdomain"
+                                                      Variant="Variant.Outlined"
+                                                      HelperText="Nur Kleinbuchstaben, Zahlen & Bindestriche (z.B. acme)"
+                                                      @bind-Value="_firmModel.Subdomain"
+                                                      Required="true"
+                                                      Adornment="Adornment.End"
+                                                      AdornmentText="@GetDomainSuffix()" />
+
+                                        <MudDivider Class="my-2" />
+                                        <MudText Typo="Typo.subtitle2" Style="font-weight:700;">Administrator-Konto</MudText>
+
+                                        <MudTextField T="string"
+                                                      Label="Benutzername"
+                                                      Variant="Variant.Outlined"
+                                                      Adornment="Adornment.Start"
+                                                      AdornmentIcon="@Icons.Material.Filled.Person"
+                                                      @bind-Value="_firmModel.AdminUsername"
+                                                      Required="true"
+                                                      HelperText="Mindestens 3 Zeichen" />
+
+                                        <MudTextField T="string"
+                                                      Label="Passwort"
+                                                      Variant="Variant.Outlined"
+                                                      Adornment="Adornment.Start"
+                                                      AdornmentIcon="@Icons.Material.Filled.Lock"
+                                                      InputType="InputType.Password"
+                                                      @bind-Value="_firmModel.AdminPassword"
+                                                      Required="true"
+                                                      HelperText="Mindestens 6 Zeichen" />
+
+                                        <MudTextField T="string"
+                                                      Label="Passwort wiederholen"
+                                                      Variant="Variant.Outlined"
+                                                      Adornment="Adornment.Start"
+                                                      AdornmentIcon="@Icons.Material.Filled.Lock"
+                                                      InputType="InputType.Password"
+                                                      @bind-Value="_firmModel.ConfirmPassword"
+                                                      Required="true" />
+
+                                        <MudCheckBox @bind-Value="_acceptAgb" Color="Color.Secondary" Class="mt-1">
+                                            <MudText Typo="Typo.body2">Ich akzeptiere die <a href="/agb" target="_blank" style="color: var(--mud-palette-secondary); text-decoration: underline; font-weight: 600;">AGB</a>.</MudText>
+                                        </MudCheckBox>
+
+                                        <MudButton ButtonType="ButtonType.Submit"
+                                                   Variant="Variant.Filled"
+                                                   Color="Color.Secondary"
+                                                   FullWidth="true"
+                                                   Size="Size.Large"
+                                                   StartIcon="@Icons.Material.Filled.Business"
+                                                   Class="mt-2"
+                                                   Disabled="_loading || !_acceptAgb">
+                                            @if (_loading)
+                                            {
+                                                <MudProgressCircular Size="Size.Small" Indeterminate="true" Class="mr-2" />
+                                            }
+                                            Firma registrieren
+                                        </MudButton>
+                                    </MudStack>
+                                </EditForm>
+                            </MudStack>
+                        }
+                    }
+                }
+            </MudPaper>
+        </MudStack>
+    </MudContainer>
+}
 
 @code {
+    private TenantInfo? _tenantInfo;
     private int _activeTab = 0;
     private string? _error;
     private bool _loading;
     private string _honeypot = "";
     private bool _acceptAgb;
+    private bool _firmRegisteredSuccessfully;
 
     private readonly AuthModel _loginModel = new();
     private readonly AuthModel _registerModel = new();
+    private readonly FirmModel _firmModel = new();
 
     [SupplyParameterFromQuery(Name = "error")]
     public string? ErrorParam { get; set; }
@@ -151,6 +314,20 @@
     [SupplyParameterFromQuery(Name = "tab")]
     public string? TabParam { get; set; }
 
+    protected override async Task OnInitializedAsync()
+    {
+        try
+        {
+            _tenantInfo = await Http.GetFromJsonAsync<TenantInfo>("api/tenant/current");
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"Fehler beim Abrufen der TenantInfo: {ex.Message}");
+            // Fallback
+            _tenantInfo = new TenantInfo { IsTenant = false };
+        }
+    }
+
     protected override void OnParametersSet()
     {
         _error = ErrorParam switch
@@ -168,6 +345,35 @@
         _error = null;
     }
 
+    private string GetPageTitle()
+    {
+        if (_tenantInfo == null) return "Lade…";
+        return _tenantInfo.IsTenant ? $"Anmelden bei {_tenantInfo.Name} – Timetracker" : "Anmelden – Timetracker SaaS";
+    }
+
+    private string GetDomainSuffix()
+    {
+        var uri = new Uri(Nav.BaseUri);
+        var host = uri.Host;
+        return $".{host}";
+    }
+
+    private string GetTenantUrl()
+    {
+        var uri = new Uri(Nav.BaseUri);
+        var scheme = uri.Scheme;
+        var port = uri.Port == 80 || uri.Port == 443 ? "" : $":{uri.Port}";
+        var host = uri.Host;
+        return $"{scheme}://{_firmModel.Subdomain.ToLower().Trim()}.{host}{port}";
+    }
+
+    private void ResetRegistrationFlow()
+    {
+        _firmRegisteredSuccessfully = false;
+        _activeTab = 0;
+        _error = null;
+    }
+
     private async Task HandleLogin()
     {
         _loading = true;
@@ -177,7 +383,7 @@
             var user = await AuthService.LoginAsync(_loginModel.Username, _loginModel.Password);
             if (user != null)
             {
-                Nav.NavigateTo("/", forceLoad: true); // forceLoad forces state update/re-render of the root app
+                Nav.NavigateTo("/", forceLoad: true);
             }
             else
             {
@@ -226,9 +432,62 @@
         }
     }
 
+    private async Task HandleRegisterFirm()
+    {
+        if (!_acceptAgb)
+        {
+            _error = "Du musst die AGB akzeptieren.";
+            return;
+        }
+        if (_firmModel.AdminPassword != _firmModel.ConfirmPassword)
+        {
+            _error = "Passwörter stimmen nicht überein.";
+            return;
+        }
+
+        _loading = true;
+        _error = null;
+        try
+        {
+            var req = new RegisterFirmRequest(
+                _firmModel.CompanyName,
+                _firmModel.Subdomain,
+                _firmModel.AdminUsername,
+                _firmModel.AdminPassword
+            );
+
+            var (tenant, error) = await AuthService.RegisterFirmAsync(req);
+            if (tenant != null)
+            {
+                _firmRegisteredSuccessfully = true;
+            }
+            else
+            {
+                _error = error ?? "Registrierung der Firma fehlgeschlagen.";
+            }
+        }
+        catch (Exception ex)
+        {
+            _error = $"Registrierungs Fehler: {ex.Message}";
+        }
+        finally
+        {
+            _loading = false;
+        }
+    }
+
     private class AuthModel
     {
         public string Username { get; set; } = "";
         public string Password { get; set; } = "";
     }
+
+    private class FirmModel
+    {
+        public string CompanyName { get; set; } = "";
+        public string Subdomain { get; set; } = "";
+        public string AdminUsername { get; set; } = "";
+        public string AdminPassword { get; set; } = "";
+        public string ConfirmPassword { get; set; } = "";
+    }
 }

timetracker.Client/Components/Pages/Month.razor

@@ -19,29 +19,28 @@ else
     <MudStack Spacing="3">
 
         @* ── Monats-Header ── *@
-        <MudPaper Elevation="4" Class="pa-5 rounded-xl"
+        <MudPaper Elevation="4" Class="pa-5 rounded-xl mud-theme-primary">
-                  Style="background: #1E293B; color: white;">
             <MudStack Row="true" AlignItems="AlignItems.Center" Justify="Justify.SpaceBetween">
                 <MudIconButton Icon="@Icons.Material.Filled.ChevronLeft"
-                               Style="color:white" Size="Size.Large" OnClick="PrevMonth" />
+                               Style="color: var(--mud-palette-primary-text)" Size="Size.Large" OnClick="PrevMonth" />
                 <MudStack Spacing="0" AlignItems="AlignItems.Center">
-                    <MudText Typo="Typo.h5" Style="color:white; font-weight:700; letter-spacing:0.5px">
+                    <MudText Typo="Typo.h5" Style="color: var(--mud-palette-primary-text); font-weight:700; letter-spacing:0.5px">
                         @_deCulture.DateTimeFormat.GetMonthName(_month) @_year
                     </MudText>
-                    <MudText Typo="Typo.caption" Style="color:rgba(255,255,255,0.72)">
+                    <MudText Typo="Typo.caption" Style="color: var(--mud-palette-primary-text); opacity: 0.72">
                         @_subLabel
                     </MudText>
                 </MudStack>
                 <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="0">
                     @if (!IsCurrentMonth)
                     {
-                        <MudButton Variant="Variant.Text" Style="color:white"
+                        <MudButton Variant="Variant.Text" Style="color: var(--mud-palette-primary-text)"
                                    OnClick="GoToCurrentMonth" Size="Size.Small">
                             Heute
                         </MudButton>
                     }
                     <MudIconButton Icon="@Icons.Material.Filled.ChevronRight"
-                                   Style="color:white" Size="Size.Large" OnClick="NextMonth" />
+                                   Style="color: var(--mud-palette-primary-text)" Size="Size.Large" OnClick="NextMonth" />
                 </MudStack>
             </MudStack>
         </MudPaper>
@@ -95,7 +94,7 @@ else
 
         @* ── Monatszusammenfassung ── *@
         <MudPaper Elevation="4" Class="pa-5 rounded-xl"
-                  Style="background: linear-gradient(135deg, rgba(14,165,233,0.08) 0%, rgba(14,165,233,0.02) 100%); border-left: 6px solid #0EA5E9;">
+                  Style="background: linear-gradient(135deg, color-mix(in srgb, var(--mud-palette-primary) 8%, transparent) 0%, color-mix(in srgb, var(--mud-palette-primary) 2%, transparent) 100%); border-left: 6px solid var(--mud-palette-primary);">
             <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="2" Class="mb-4">
                 <MudIcon Icon="@Icons.Material.Filled.CalendarViewMonth" Color="Color.Primary" />
                 <MudText Typo="Typo.h6" Style="font-weight:700">Monatszusammenfassung</MudText>

timetracker.Client/Components/Pages/Profile.razor

@@ -22,13 +22,12 @@ else
     <MudStack Spacing="4">
 
         @* ── Header ── *@
-        <MudPaper Elevation="4" Class="pa-5 rounded-xl"
+        <MudPaper Elevation="4" Class="pa-5 rounded-xl mud-theme-primary">
-                  Style="background: #1E293B; color:white;">
             <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="3">
-                <MudIcon Icon="@Icons.Material.Filled.AccountCircle" Style="color:white; font-size:2.5rem" />
+                <MudIcon Icon="@Icons.Material.Filled.AccountCircle" Style="color: var(--mud-palette-primary-text); font-size:2.5rem" />
                 <MudStack Spacing="0">
-                    <MudText Typo="Typo.h5" Style="color:white; font-weight:700">Mein Profil</MudText>
+                    <MudText Typo="Typo.h5" Style="color: var(--mud-palette-primary-text); font-weight:700">Mein Profil</MudText>
-                    <MudText Typo="Typo.caption" Style="color:rgba(255,255,255,0.72)">
+                    <MudText Typo="Typo.caption" Style="color: var(--mud-palette-primary-text); opacity: 0.72;">
                         Persönliche Details verwalten und Account sichern
                     </MudText>
                 </MudStack>

timetracker.Client/Components/Pages/ResetPasswordDialog.razor

@@ -0,0 +1,29 @@
+@namespace timetracker.Client.Components.Pages
+@inject ISnackbar Snackbar
+
+<MudDialog>
+    <DialogContent>
+        <MudText Class="mb-4">Geben Sie das neue Passwort für den Benutzer <strong>@Username</strong> ein.</MudText>
+        <MudTextField @bind-Value="_newPassword" 
+                      Label="Neues Passwort" 
+                      InputType="InputType.Password" 
+                      Variant="Variant.Outlined" 
+                      AutoFocus="true"
+                      Required="true"
+                      HelperText="Mindestens 6 Zeichen" />
+    </DialogContent>
+    <DialogActions>
+        <MudButton OnClick="Cancel">Abbrechen</MudButton>
+        <MudButton Color="Color.Warning" Variant="Variant.Filled" OnClick="Submit" Disabled="@(string.IsNullOrEmpty(_newPassword) || _newPassword.Length < 6)">Passwort zurücksetzen</MudButton>
+    </DialogActions>
+</MudDialog>
+
+@code {
+    [CascadingParameter] IMudDialogInstance MudDialog { get; set; } = default!;
+    [Parameter] public string Username { get; set; } = "";
+
+    private string _newPassword = "";
+
+    private void Submit() => MudDialog.Close(DialogResult.Ok(_newPassword));
+    private void Cancel() => MudDialog.Cancel();
+}

timetracker.Client/Components/Pages/Settings.razor

@@ -7,6 +7,7 @@
 @inject AuthenticationStateProvider AuthStateProvider
 @inject IJSRuntime JSRuntime
 @inject NavigationManager Nav
+@inject HttpClient Http
 
 
 <PageTitle>Einstellungen – Timetracker</PageTitle>
@@ -22,13 +23,12 @@ else
     <MudStack Spacing="4">
 
         @* ── Header ── *@
-        <MudPaper Elevation="4" Class="pa-5 rounded-xl"
+        <MudPaper Elevation="4" Class="pa-5 rounded-xl mud-theme-primary">
-                  Style="background: #1E293B; color:white;">
             <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="3">
-                <MudIcon Icon="@Icons.Material.Filled.Settings" Style="color:white; font-size:2rem" />
+                <MudIcon Icon="@Icons.Material.Filled.Settings" Style="color: var(--mud-palette-primary-text); font-size:2rem" />
                 <MudStack Spacing="0">
-                    <MudText Typo="Typo.h5" Style="color:white; font-weight:700">Einstellungen</MudText>
+                    <MudText Typo="Typo.h5" Style="color: var(--mud-palette-primary-text); font-weight:700">Einstellungen</MudText>
-                    <MudText Typo="Typo.caption" Style="color:rgba(255,255,255,0.72)">
+                    <MudText Typo="Typo.caption" Style="color: var(--mud-palette-primary-text); opacity: 0.72">
                         Arbeitszeit, Arbeitstage und Urlaub konfigurieren
                     </MudText>
                 </MudStack>
@@ -217,6 +217,52 @@ else
                 </MudCard>
             </MudItem>
 
+            @if (_isTenantAdmin)
+            {
+                @* ── Firmen-Einstellungen (Branding) ── *@
+                <MudItem xs="12" md="6">
+                    <MudCard Elevation="3" Class="rounded-xl h-100">
+                        <MudCardHeader>
+                            <CardHeaderContent>
+                                <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="2">
+                                    <MudIcon Icon="@Icons.Material.Filled.Business" Color="Color.Primary" />
+                                    <MudText Typo="Typo.h6" Style="font-weight:600">Firmen-Einstellungen</MudText>
+                                </MudStack>
+                            </CardHeaderContent>
+                        </MudCardHeader>
+                        <MudCardContent>
+                            <MudStack Spacing="4">
+                                <MudTextField @bind-Value="_tenantName"
+                                              Label="Firmenname"
+                                              Variant="Variant.Outlined"
+                                              HelperText="Der offizielle Name deiner Firma" />
+                                
+                                <MudStack Row="true" Spacing="4">
+                                    <MudColorPicker @bind-Text="_tenantPrimaryColor"
+                                                    Label="Primärfarbe"
+                                                    Variant="Variant.Outlined"
+                                                    Style="@($"color: {_tenantPrimaryColor};")"
+                                                    ColorPickerMode="ColorPickerMode.HEX" />
+                                    
+                                    <MudColorPicker @bind-Text="_tenantSecondaryColor"
+                                                    Label="Sekundärfarbe"
+                                                    Variant="Variant.Outlined"
+                                                    Style="@($"color: {_tenantSecondaryColor};")"
+                                                    ColorPickerMode="ColorPickerMode.HEX" />
+                                </MudStack>
+
+                                <MudButton Variant="Variant.Filled" Color="Color.Primary"
+                                           StartIcon="@Icons.Material.Filled.Save"
+                                           OnClick="SaveTenantSettings"
+                                           Style="max-width:250px;">
+                                    Firma speichern
+                                </MudButton>
+                            </MudStack>
+                        </MudCardContent>
+                    </MudCard>
+                </MudItem>
+            }
+
         </MudGrid>
 
         @* ── Speichern-Button ── *@
@@ -467,6 +513,11 @@ else
 
     private AppSettings? _settings;
     private int _userId;
+    private bool _isTenantAdmin;
+    private TenantInfo? _tenantInfo;
+    private string _tenantName = "";
+    private string _tenantPrimaryColor = "#0EA5E9";
+    private string _tenantSecondaryColor = "#0EA5E9";
     private DateTime? _flexStartDate
     {
         get => _settings?.FlexTimeStartDate?.ToDateTime(TimeOnly.MinValue);
@@ -526,6 +577,25 @@ else
         _userId = int.Parse(claim.Value);
         _settings = await TrackerService.GetSettingsAsync(_userId);
 
+        _isTenantAdmin = authState.User.IsInRole("TenantAdmin") || authState.User.HasClaim("IsTenantAdmin", "true");
+        if (_isTenantAdmin)
+        {
+            try
+            {
+                _tenantInfo = await Http.GetFromJsonAsync<TenantInfo>("api/tenant/current");
+                if (_tenantInfo != null)
+                {
+                    _tenantName = _tenantInfo.Name ?? "";
+                    _tenantPrimaryColor = _tenantInfo.PrimaryColor ?? "#0EA5E9";
+                    _tenantSecondaryColor = _tenantInfo.SecondaryColor ?? "#0EA5E9";
+                }
+            }
+            catch (Exception ex)
+            {
+                Snackbar.Add($"Fehler beim Laden der Firmen-Einstellungen: {ex.Message}", Severity.Error);
+            }
+        }
+
         var loadVacationsTask = LoadVacations();
         var loadHolidaysTask = HolidayService.GetHolidaysAsync(_holYear, _settings.GermanState);
 
@@ -622,6 +692,35 @@ else
         }
     }
 
+    private async Task SaveTenantSettings()
+    {
+        if (string.IsNullOrWhiteSpace(_tenantName))
+        {
+            Snackbar.Add("Bitte einen Firmennamen eingeben.", Severity.Warning);
+            return;
+        }
+
+        var dto = new TenantSettingsDto
+        {
+            Name = _tenantName.Trim(),
+            PrimaryColor = _tenantPrimaryColor,
+            SecondaryColor = _tenantSecondaryColor
+        };
+
+        var response = await Http.PostAsJsonAsync("api/tracker/tenant/settings", dto);
+        if (response.IsSuccessStatusCode)
+        {
+            Snackbar.Add("Firmen-Einstellungen gespeichert. Lade Seite neu...", Severity.Success);
+            await Task.Delay(1000);
+            Nav.NavigateTo(Nav.Uri, forceLoad: true);
+        }
+        else
+        {
+            var err = await response.Content.ReadAsStringAsync();
+            Snackbar.Add($"Fehler beim Speichern: {err}", Severity.Error);
+        }
+    }
+
     private static string FormatHours(double hours)
     {
         var ts = TimeSpan.FromHours(hours);

timetracker.Client/Components/Pages/Stats.razor

@@ -20,12 +20,12 @@ else
     <MudStack Spacing="4">
         
         @* ── Header ── *@
-        <MudPaper Elevation="4" Class="pa-5 rounded-xl" Style="background: #1E293B; color: white;">
+        <MudPaper Elevation="4" Class="pa-5 rounded-xl mud-theme-primary">
             <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="3">
-                <MudIcon Icon="@Icons.Material.Filled.BarChart" Style="color:white; font-size:2.2rem" />
+                <MudIcon Icon="@Icons.Material.Filled.BarChart" Style="color: var(--mud-palette-primary-text); font-size:2.2rem" />
                 <MudStack Spacing="0">
-                    <MudText Typo="Typo.h5" Style="color:white; font-weight:700">Statistiken</MudText>
+                    <MudText Typo="Typo.h5" Style="color: var(--mud-palette-primary-text); font-weight:700">Statistiken</MudText>
-                    <MudText Typo="Typo.caption" Style="color:rgba(255,255,255,0.72)">Auswertung deiner Arbeitsleistung und Gleitzeitkonto</MudText>
+                    <MudText Typo="Typo.caption" Style="color: var(--mud-palette-primary-text); opacity: 0.72">Auswertung deiner Arbeitsleistung und Gleitzeitkonto</MudText>
                 </MudStack>
             </MudStack>
         </MudPaper>
@@ -46,7 +46,7 @@ else
                             <div style="position:relative; display:inline-flex;">
                                 <MudProgressCircular Value="@pct" Color="Color.Secondary" Size="Size.Large" StrokeWidth="6" Style="height:120px; width:120px;" />
                                 <div style="position:absolute; top:0; left:0; bottom:0; right:0; display:flex; align-items:center; justify-content:center; flex-direction:column;">
-                                    <MudText Typo="Typo.h5" Style="font-weight:800; color:#0F172A;">@displayPct%</MudText>
+                                    <MudText Typo="Typo.h5" Style="font-weight:800; color: var(--mud-palette-text-primary);">@displayPct%</MudText>
                                     <MudText Typo="Typo.caption" Color="Color.Secondary">Erreicht</MudText>
                                 </div>
                             </div>
@@ -54,7 +54,7 @@ else
                             <MudStack Spacing="1" Style="width:100%;" Class="mt-2">
                                 <MudStack Row="true" Justify="Justify.SpaceBetween">
                                     <MudText Typo="Typo.body2" Color="Color.Secondary">Arbeitszeit (Ist):</MudText>
-                                    <MudText Typo="Typo.body2" Style="font-weight:700; color:#0F172A">@FormatHours(_weekWorkedHours) Std.</MudText>
+                                    <MudText Typo="Typo.body2" Style="font-weight:700; color: var(--mud-palette-text-primary)">@FormatHours(_weekWorkedHours) Std.</MudText>
                                 </MudStack>
                                 <MudStack Row="true" Justify="Justify.SpaceBetween">
                                     <MudText Typo="Typo.body2" Color="Color.Secondary">Wochensoll (Soll):</MudText>
@@ -68,7 +68,7 @@ else
 
             @* ── Card 2: Wochensaldo ── *@
             <MudItem xs="12" sm="6" md="4">
-                <MudCard Elevation="3" Class="rounded-xl" Style="height:100%; border-left: 6px solid #0EA5E9;">
+                <MudCard Elevation="3" Class="rounded-xl" Style="height:100%; border-left: 6px solid var(--mud-palette-primary);">
                     <MudCardContent>
                         <MudStack Spacing="2">
                             <MudText Typo="Typo.subtitle1" Style="font-weight:700; color:#475569">Wochensaldo</MudText>
@@ -115,7 +115,7 @@ else
                 <MudCard Elevation="3" Class="rounded-xl">
                     <MudCardHeader>
                         <CardHeaderContent>
-                            <MudText Typo="Typo.h6" Style="font-weight:700; color:#0F172A">Arbeitszeitverteilung diese Woche</MudText>
+                            <MudText Typo="Typo.h6" Style="font-weight:700; color: var(--mud-palette-text-primary)">Arbeitszeitverteilung diese Woche</MudText>
                             <MudText Typo="Typo.caption" Color="Color.Secondary">Geleistete Nettoarbeitsstunden pro Wochentag</MudText>
                         </CardHeaderContent>
                     </MudCardHeader>
@@ -148,8 +148,8 @@ else
                                 {
                                     double val = (_maxHoursValue / 4.0) * i;
                                     double yPos = plotBottom - (val / _maxHoursValue) * plotHeight;
-                                    <line x1="@plotLeft" y1="@yPos" x2="@plotRight" y2="@yPos" stroke="#E2E8F0" stroke-width="1" stroke-dasharray="2" />
+                                    <line x1="@F(plotLeft)" y1="@F(yPos)" x2="@F(plotRight)" y2="@F(yPos)" stroke="#E2E8F0" stroke-width="1" stroke-dasharray="2" />
-                                    @((MarkupString)$"<text x=\"{plotLeft - 8}\" y=\"{yPos + 4}\" fill=\"#64748B\" font-size=\"11\" font-weight=\"500\" text-anchor=\"end\">{val:F1}h</text>")
+                                    @((MarkupString)$"<text x=\"{F(plotLeft - 8)}\" y=\"{F(yPos + 4)}\" fill=\"#64748B\" font-size=\"11\" font-weight=\"500\" text-anchor=\"end\">{val:F1}h</text>")
                                 }
 
                                 <!-- Bars and Labels -->
@@ -163,7 +163,7 @@ else
                                     string fillCol = "#94A3B8"; // Default light slate
                                     if (d.IsToday)
                                     {
-                                        fillCol = "#0EA5E9"; // Sky Blue for today
+                                        fillCol = "var(--mud-palette-secondary)"; // Brand color for today
                                     }
                                     else if (d.WorkedHours >= d.TargetHours && d.TargetHours > 0)
                                     {
@@ -183,7 +183,7 @@ else
                                     }
 
                                     <!-- Render Rect with hover tooltip -->
-                                    <rect x="@xPos" y="@(d.WorkedHours > 0 ? yPos : plotBottom - 4)" width="@barWidth" height="@(d.WorkedHours > 0 ? bHeight : 4)" 
+                                    <rect x="@F(xPos)" y="@F(d.WorkedHours > 0 ? yPos : plotBottom - 4)" width="@F(barWidth)" height="@F(d.WorkedHours > 0 ? bHeight : 4)" 
                                           rx="6" fill="@fillCol" class="chart-bar">
                                         <title>@d.DayName: @FormatHours(d.WorkedHours) Std. (Soll: @FormatHours(d.TargetHours) Std.)</title>
                                     </rect>
@@ -191,19 +191,19 @@ else
                                     <!-- Value Label above bar -->
                                     @if (d.WorkedHours > 0)
                                     {
-                                        @((MarkupString)$"<text x=\"{xPos + barWidth / 2}\" y=\"{yPos - 6}\" fill=\"#0F172A\" font-size=\"11\" font-weight=\"700\" text-anchor=\"middle\">{FormatHours(d.WorkedHours)}</text>")
+                                        @((MarkupString)$"<text x=\"{F(xPos + barWidth / 2)}\" y=\"{F(yPos - 6)}\" fill=\"var(--mud-palette-text-primary)\" font-size=\"11\" font-weight=\"700\" text-anchor=\"middle\">{FormatHours(d.WorkedHours)}</text>")
                                     }
 
                                     <!-- Wochentag Text -->
-                                    @((MarkupString)$"<text x=\"{xPos + barWidth / 2}\" y=\"{plotBottom + 20}\" fill=\"#64748B\" font-size=\"11\" font-weight=\"700\" text-anchor=\"middle\">{d.DayShortName}</text>")
+                                    @((MarkupString)$"<text x=\"{F(xPos + barWidth / 2)}\" y=\"{F(plotBottom + 20)}\" fill=\"#64748B\" font-size=\"11\" font-weight=\"700\" text-anchor=\"middle\">{d.DayShortName}</text>")
                                 }
 
                                 <!-- Sollzeit Target Line (Only if target hours > 0) -->
                                 @if (_settings.DailyTargetHours > 0)
                                 {
                                     double yTarget = plotBottom - (_settings.DailyTargetHours / _maxHoursValue) * plotHeight;
-                                    <line x1="@plotLeft" y1="@yTarget" x2="@plotRight" y2="@yTarget" stroke="#EF4444" stroke-width="2" stroke-dasharray="4" style="opacity: 0.75;" />
+                                    <line x1="@F(plotLeft)" y1="@F(yTarget)" x2="@F(plotRight)" y2="@F(yTarget)" stroke="#EF4444" stroke-width="2" stroke-dasharray="4" style="opacity: 0.75;" />
-                                    @((MarkupString)$"<text x=\"{plotRight - 10}\" y=\"{yTarget - 6}\" fill=\"#EF4444\" font-size=\"10\" font-weight=\"700\" text-anchor=\"end\">Soll ({_settings.DailyTargetHours} h)</text>")
+                                    @((MarkupString)$"<text x=\"{F(plotRight - 10)}\" y=\"{F(yTarget - 6)}\" fill=\"#EF4444\" font-size=\"10\" font-weight=\"700\" text-anchor=\"end\">Soll ({_settings.DailyTargetHours} h)</text>")
                                 }
                             </svg>
                         </div>
@@ -269,6 +269,7 @@ else
     private Dictionary<DateOnly, string> _dbMatchStatus = new();
     
     private static readonly System.Globalization.CultureInfo _deCulture = new("de-DE");
+    private static string F(double value) => value.ToString("F2", System.Globalization.CultureInfo.InvariantCulture);
 
     protected override async Task OnInitializedAsync()
     {

timetracker.Client/Components/Pages/SuperAdmin.razor

@@ -0,0 +1,267 @@
+@page "/superadmin"
+@rendermode InteractiveWebAssembly
+@attribute [Authorize(Policy = "AdminOnly")]
+@using System.Net.Http.Json
+@inject HttpClient Http
+@inject ISnackbar Snackbar
+@inject IDialogService DialogService
+
+<PageTitle>Firmenverwaltung – Timetracker SaaS</PageTitle>
+
+@if (_loading)
+{
+    <MudStack AlignItems="AlignItems.Center" Class="mt-16" Spacing="3">
+        <MudProgressCircular Color="Color.Primary" Indeterminate="true" Size="Size.Large" />
+        <MudText Color="Color.Secondary">Lade Firmen und Mandanten…</MudText>
+    </MudStack>
+}
+else
+{
+    <MudStack Spacing="4">
+
+        @* ── Header Card ── *@
+        <MudPaper Elevation="4" Class="pa-6 rounded-xl"
+                  Style="background: linear-gradient(135deg, var(--mud-palette-primary-darken) 0%, var(--mud-palette-primary) 100%); color: var(--mud-palette-primary-text);">
+            <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="4">
+                <MudIcon Icon="@Icons.Material.Filled.Business" Style="color: var(--mud-palette-secondary); font-size:3rem" />
+                <MudStack Spacing="0">
+                    <MudText Typo="Typo.h5" Style="color: var(--mud-palette-primary-text); font-weight:800">SuperAdmin Dashboard</MudText>
+                    <MudText Typo="Typo.body2" Style="color: var(--mud-palette-primary-text); opacity: 0.72">
+                        @_tenants.Count registrierte Firmen im System
+                    </MudText>
+                </MudStack>
+            </MudStack>
+        </MudPaper>
+
+        @* ── Tenants Table ── *@
+        <MudCard Elevation="3" Class="rounded-xl overflow-hidden">
+            <MudCardContent Class="pa-0">
+                <MudTable Items="_tenants" Hover="true" Striped="true" Elevation="0" SortLabel="Sortieren">
+                    <HeaderContent>
+                        <MudTh Style="width: 50px;" />
+                        <MudTh><MudTableSortLabel SortBy="new Func<TenantStats, object>(t => t.Id)">ID</MudTableSortLabel></MudTh>
+                        <MudTh><MudTableSortLabel SortBy="new Func<TenantStats, object>(t => t.Name)">Name</MudTableSortLabel></MudTh>
+                        <MudTh><MudTableSortLabel SortBy="new Func<TenantStats, object>(t => t.Subdomain)">Subdomain</MudTableSortLabel></MudTh>
+                        <MudTh><MudTableSortLabel SortBy="new Func<TenantStats, object>(t => t.CreatedAt)">Erstellt am</MudTableSortLabel></MudTh>
+                        <MudTh Style="text-align:center"><MudTableSortLabel SortBy="new Func<TenantStats, object>(t => t.UserCount)">Benutzer</MudTableSortLabel></MudTh>
+                        <MudTh Style="text-align:center"><MudTableSortLabel SortBy="new Func<TenantStats, object>(t => t.WorkDaysCount)">Arbeitstage</MudTableSortLabel></MudTh>
+                        <MudTh Style="text-align:center">Status</MudTh>
+                        <MudTh Style="text-align:right">Aktionen</MudTh>
+                    </HeaderContent>
+                    <RowTemplate>
+                        <MudTd>
+                            <MudIconButton Icon="@(context.ShowDetails ? Icons.Material.Filled.ExpandLess : Icons.Material.Filled.ExpandMore)"
+                                           Size="Size.Small"
+                                           OnClick="@(() => context.ShowDetails = !context.ShowDetails)" />
+                        </MudTd>
+                        <MudTd DataLabel="ID">
+                            <MudText Typo="Typo.body2" Color="Color.Secondary">@context.Id</MudText>
+                        </MudTd>
+                        <MudTd DataLabel="Name">
+                            <MudText Typo="Typo.body1" Style="font-weight:600">@context.Name</MudText>
+                        </MudTd>
+                        <MudTd DataLabel="Subdomain">
+                            <MudChip T="string" Color="Color.Primary" Variant="Variant.Outlined" Size="Size.Small">
+                                @context.Subdomain
+                            </MudChip>
+                        </MudTd>
+                        <MudTd DataLabel="Erstellt am">
+                            <MudText Typo="Typo.body2">@context.CreatedAt.ToLocalTime().ToString("dd.MM.yyyy HH:mm")</MudText>
+                        </MudTd>
+                        <MudTd DataLabel="Benutzer" Style="text-align:center">
+                            <MudBadge Content="@context.UserCount" Color="Color.Default" Overlap="false" Class="mx-2" />
+                        </MudTd>
+                        <MudTd DataLabel="Arbeitstage" Style="text-align:center">
+                            <MudText Typo="Typo.body2">@context.WorkDaysCount</MudText>
+                        </MudTd>
+                        <MudTd DataLabel="Status" Style="text-align:center">
+                            @if (context.IsApproved)
+                            {
+                                <MudChip T="string" Color="Color.Success" Size="Size.Small" Icon="@Icons.Material.Filled.Check">Aktiv</MudChip>
+                            }
+                            else
+                            {
+                                <MudChip T="string" Color="Color.Warning" Size="Size.Small" Icon="@Icons.Material.Filled.HourglassEmpty">Ausstehend</MudChip>
+                            }
+                        </MudTd>
+                        <MudTd Style="text-align:right">
+                            @if (!context.IsApproved)
+                            {
+                                <MudButton Variant="Variant.Filled" 
+                                           Color="Color.Success" 
+                                           Size="Size.Small" 
+                                           StartIcon="@Icons.Material.Filled.CheckCircle" 
+                                           OnClick="@(() => ApproveTenant(context))"
+                                           Class="mr-1">
+                                    Freigeben
+                                </MudButton>
+                            }
+                            else
+                            {
+                                <MudButton Variant="Variant.Outlined" 
+                                           Color="Color.Warning" 
+                                           Size="Size.Small" 
+                                           StartIcon="@Icons.Material.Filled.Block" 
+                                           OnClick="@(() => ToggleActiveTenant(context))"
+                                           Class="mr-1">
+                                    Sperren
+                                </MudButton>
+                            }
+                            <MudIconButton Icon="@Icons.Material.Filled.Delete" 
+                                           Color="Color.Error" 
+                                           Size="Size.Small" 
+                                           OnClick="@(() => DeleteTenant(context))" />
+                        </MudTd>
+                    </RowTemplate>
+                    <ChildRowContent>
+                        @if (context.ShowDetails)
+                        {
+                            <MudTr>
+                                <td colspan="9" style="background-color: var(--mud-palette-background-grey); padding: 16px;">
+                                    <MudPaper Elevation="1" Class="pa-4 rounded-lg">
+                                        <MudText Typo="Typo.subtitle2" Class="mb-3" Style="font-weight: 700;">
+                                            Benutzer für Firma: @context.Name
+                                        </MudText>
+                                        @if (context.Users == null || context.Users.Count == 0)
+                                        {
+                                            <MudText Typo="Typo.body2" Color="Color.Secondary">Keine Benutzer in dieser Firma registriert.</MudText>
+                                        }
+                                        else
+                                        {
+                                            <MudGrid Spacing="2">
+                                                @foreach (var user in context.Users)
+                                                {
+                                                    <MudItem xs="12" sm="6" md="4">
+                                                        <MudPaper Outlined="true" Class="pa-3 rounded-lg d-flex align-center justify-space-between" Style="background: white;">
+                                                            <MudStack Row="true" AlignItems="AlignItems.Center" Spacing="2">
+                                                                <MudAvatar Color="user.IsTenantAdmin ? Color.Primary : Color.Default" Size="Size.Small">
+                                                                    @user.Username.Substring(0, Math.Min(2, user.Username.Length)).ToUpper()
+                                                                </MudAvatar>
+                                                                <MudStack Spacing="0">
+                                                                    <MudText Typo="Typo.body2" Style="font-weight: 600;">@user.Username</MudText>
+                                                                    <MudText Typo="Typo.caption" Color="Color.Secondary">ID: @user.Id</MudText>
+                                                                </MudStack>
+                                                            </MudStack>
+                                                            @if (user.IsTenantAdmin)
+                                                            {
+                                                                <MudChip T="string" Color="Color.Primary" Size="Size.Small" Variant="Variant.Text" Icon="@Icons.Material.Filled.AdminPanelSettings">Admin</MudChip>
+                                                            }
+                                                            else
+                                                            {
+                                                                <MudChip T="string" Color="Color.Default" Size="Size.Small" Variant="Variant.Text" Icon="@Icons.Material.Filled.Person">Mitarbeiter</MudChip>
+                                                            }
+                                                        </MudPaper>
+                                                    </MudItem>
+                                                }
+                                            </MudGrid>
+                                        }
+                                    </MudPaper>
+                                </td>
+                            </MudTr>
+                        }
+                    </ChildRowContent>
+                </MudTable>
+            </MudCardContent>
+        </MudCard>
+    </MudStack>
+}
+
+@code {
+    private bool _loading = true;
+    private List<TenantStats> _tenants = [];
+
+    protected override async Task OnInitializedAsync()
+    {
+        await LoadTenants();
+    }
+
+    private async Task LoadTenants()
+    {
+        _loading = true;
+        try
+        {
+            _tenants = await Http.GetFromJsonAsync<List<TenantStats>>("api/superadmin/tenants") ?? [];
+        }
+        catch (Exception ex)
+        {
+            Snackbar.Add($"Fehler beim Laden der Firmen: {ex.Message}", Severity.Error);
+        }
+        finally
+        {
+            _loading = false;
+        }
+    }
+
+    private async Task ApproveTenant(TenantStats tenant)
+    {
+        try
+        {
+            var response = await Http.PostAsync($"api/superadmin/tenants/{tenant.Id}/approve", null);
+            if (response.IsSuccessStatusCode)
+            {
+                tenant.IsApproved = true;
+                Snackbar.Add($"Firma '{tenant.Name}' wurde erfolgreich freigegeben.", Severity.Success);
+            }
+            else
+            {
+                Snackbar.Add("Fehler bei der Freigabe.", Severity.Error);
+            }
+        }
+        catch (Exception ex)
+        {
+            Snackbar.Add($"Fehler: {ex.Message}", Severity.Error);
+        }
+    }
+
+    private async Task ToggleActiveTenant(TenantStats tenant)
+    {
+        try
+        {
+            var response = await Http.PostAsync($"api/superadmin/tenants/{tenant.Id}/toggle-active", null);
+            if (response.IsSuccessStatusCode)
+            {
+                tenant.IsApproved = !tenant.IsApproved;
+                var stateMsg = tenant.IsApproved ? "aktiviert" : "gesperrt";
+                Snackbar.Add($"Firma '{tenant.Name}' wurde {stateMsg}.", Severity.Info);
+            }
+            else
+            {
+                Snackbar.Add("Fehler beim Ändern des Status.", Severity.Error);
+            }
+        }
+        catch (Exception ex)
+        {
+            Snackbar.Add($"Fehler: {ex.Message}", Severity.Error);
+        }
+    }
+
+    private async Task DeleteTenant(TenantStats tenant)
+    {
+        bool? result = await DialogService.ShowMessageBoxAsync(
+            "Firma unwiderruflich löschen?",
+            $"Sind Sie sicher, dass Sie die Firma '{tenant.Name}' ({tenant.Subdomain}) inklusive ALLER zugehörigen Benutzer, Einstellungen und Zeiterfassungen unwiderruflich löschen möchten? Dieser Vorgang kann nicht rückgängig gemacht werden!",
+            yesText: "Löschen", cancelText: "Abbrechen");
+
+        if (result == true)
+        {
+            try
+            {
+                var response = await Http.DeleteAsync($"api/superadmin/tenants/{tenant.Id}");
+                if (response.IsSuccessStatusCode)
+                {
+                    _tenants.Remove(tenant);
+                    Snackbar.Add($"Firma '{tenant.Name}' wurde gelöscht.", Severity.Success);
+                }
+                else
+                {
+                    var err = await response.Content.ReadAsStringAsync();
+                    Snackbar.Add($"Fehler beim Löschen: {err}", Severity.Error);
+                }
+            }
+            catch (Exception ex)
+            {
+                Snackbar.Add($"Fehler: {ex.Message}", Severity.Error);
+            }
+        }
+    }
+}

timetracker.Client/Services/ClientAuthService.cs

@@ -81,4 +81,38 @@ public class ClientAuthService : IAuthService
         }
         return null;
     }
+
+    public async Task<(Tenant? Tenant, string? Error)> RegisterFirmAsync(RegisterFirmRequest req)
+    {
+        var response = await _http.PostAsJsonAsync("api/auth/register-firm", req);
+        if (response.IsSuccessStatusCode)
+        {
+            return (new Tenant { Name = req.CompanyName, Subdomain = req.Subdomain }, null);
+        }
+        else
+        {
+            var error = await response.Content.ReadAsStringAsync();
+            return (null, error);
+        }
+    }
+
+    public async Task<string?> AssignTenantAsync(int userId, int? tenantId)
+    {
+        var response = await _http.PutAsJsonAsync($"api/users/{userId}/assign-tenant", new AssignTenantRequest(tenantId));
+        if (!response.IsSuccessStatusCode)
+        {
+            return await response.Content.ReadAsStringAsync();
+        }
+        return null;
+    }
+
+    public async Task<string?> ResetPasswordAsync(int userId, string newPassword)
+    {
+        var response = await _http.PutAsJsonAsync($"api/users/{userId}/reset-password", new ResetPasswordRequest(newPassword));
+        if (!response.IsSuccessStatusCode)
+        {
+            return await response.Content.ReadAsStringAsync();
+        }
+        return null;
+    }
 }

timetracker.Client/Services/HostAuthenticationStateProvider.cs

@@ -34,7 +34,9 @@ public class HostAuthenticationStateProvider : AuthenticationStateProvider
                     var claims = new[]
                     {
                         new Claim(ClaimTypes.NameIdentifier, userInfo.Id.ToString()),
-                        new Claim(ClaimTypes.Name, userInfo.Username)
+                        new Claim(ClaimTypes.Name, userInfo.Username),
+                        new Claim("IsTenantAdmin", userInfo.IsTenantAdmin ? "true" : "false"),
+                        new Claim(ClaimTypes.Role, userInfo.IsTenantAdmin ? "TenantAdmin" : "Employee")
                     };
                     var identity = new ClaimsIdentity(claims, "Cookie");
                     _currentUser = new ClaimsPrincipal(identity);
@@ -58,7 +60,9 @@ public class HostAuthenticationStateProvider : AuthenticationStateProvider
             var claims = new[]
             {
                 new Claim(ClaimTypes.NameIdentifier, userInfo.Id.ToString()),
-                new Claim(ClaimTypes.Name, userInfo.Username)
+                new Claim(ClaimTypes.Name, userInfo.Username),
+                new Claim("IsTenantAdmin", userInfo.IsTenantAdmin ? "true" : "false"),
+                new Claim(ClaimTypes.Role, userInfo.IsTenantAdmin ? "TenantAdmin" : "Employee")
             };
             var identity = new ClaimsIdentity(claims, "Cookie");
             _currentUser = new ClaimsPrincipal(identity);

timetracker.Server/Data/AuthService.cs

@@ -1,15 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
 using System.Security.Cryptography;
 using System.Text;
+using System.Threading.Tasks;
 using Microsoft.EntityFrameworkCore;
 using timetracker.Shared;
 
 namespace timetracker.Data;
 
-public class AuthService(IDbContextFactory<TimetrackerDbContext> factory, UserNotificationService notifier) : IAuthService
+public class AuthService(
+    IDbContextFactory<TimetrackerDbContext> factory, 
+    UserNotificationService notifier,
+    ITenantProvider tenantProvider) : IAuthService
 {
     public async Task<User?> LoginAsync(string username, string password)
     {
         await using var db = await factory.CreateDbContextAsync();
+        // Global query filter automatically restricts lookup to current tenant context
         var user = await db.Users
             .FirstOrDefaultAsync(u => u.Username == username);
         if (user == null) return null;
@@ -19,7 +27,9 @@ public class AuthService(IDbContextFactory<TimetrackerDbContext> factory, UserNo
     public async Task<List<User>> GetAllUsersAsync()
     {
         await using var db = await factory.CreateDbContextAsync();
+        // Superadmin bypasses query filters to manage all users globally
         return await db.Users
+            .IgnoreQueryFilters()
             .OrderBy(u => u.Username)
             .ToListAsync();
     }
@@ -27,7 +37,7 @@ public class AuthService(IDbContextFactory<TimetrackerDbContext> factory, UserNo
     public async Task DeleteUserAsync(int userId)
     {
         await using var db = await factory.CreateDbContextAsync();
-        var user = await db.Users.FindAsync(userId);
+        var user = await db.Users.IgnoreQueryFilters().FirstOrDefaultAsync(u => u.Id == userId);
         if (user != null)
         {
             db.Users.Remove(user);
@@ -43,12 +53,16 @@ public class AuthService(IDbContextFactory<TimetrackerDbContext> factory, UserNo
             return "Benutzername muss mindestens 3 Zeichen lang sein.";
 
         await using var db = await factory.CreateDbContextAsync();
-        if (await db.Users.AnyAsync(u => u.Username == newUsername && u.Id != userId))
+        
-            return "Benutzername bereits vergeben.";
+        // Find user ignoring filters so we can rename global admin too if needed
-
+        var user = await db.Users.IgnoreQueryFilters().FirstOrDefaultAsync(u => u.Id == userId);
-        var user = await db.Users.FindAsync(userId);
         if (user == null) return "Benutzer nicht gefunden.";
 
+        // Check if name is taken within the same tenant context
+        var isTaken = await db.Users.AnyAsync(u => u.Username == newUsername && u.Id != userId && u.TenantId == user.TenantId);
+        if (isTaken)
+            return "Benutzername in dieser Firma bereits vergeben.";
+
         user.Username = newUsername;
         await db.SaveChangesAsync();
         await notifier.NotifyUsersChangedAsync();
@@ -61,7 +75,7 @@ public class AuthService(IDbContextFactory<TimetrackerDbContext> factory, UserNo
             return "Passwort muss mindestens 6 Zeichen lang sein.";
 
         await using var db = await factory.CreateDbContextAsync();
-        var user = await db.Users.FindAsync(userId);
+        var user = await db.Users.IgnoreQueryFilters().FirstOrDefaultAsync(u => u.Id == userId);
         if (user == null) return "Benutzer nicht gefunden.";
 
         if (!VerifyPassword(currentPassword, user.PasswordHash, user.PasswordSalt))
@@ -75,24 +89,164 @@ public class AuthService(IDbContextFactory<TimetrackerDbContext> factory, UserNo
         return null;
     }
 
-    public async Task<(User? User, string? Error)> RegisterAsync(string username, string password, string? honeypot = null)    {
+    public async Task<(User? User, string? Error)> RegisterAsync(string username, string password, string? honeypot = null)
+    {
         if (string.IsNullOrWhiteSpace(username) || username.Length < 3)
             return (null, "Benutzername muss mindestens 3 Zeichen lang sein.");
         if (string.IsNullOrWhiteSpace(password) || password.Length < 6)
             return (null, "Passwort muss mindestens 6 Zeichen lang sein.");
 
+        var tenantId = tenantProvider.TenantId;
+        if (tenantId == null)
+        {
+            return (null, "Mitarbeiter-Registrierung ist nur über die Firmen-Subdomain möglich.");
+        }
+
         await using var db = await factory.CreateDbContextAsync();
+        // Filter handles checking uniqueness within the same tenant
         if (await db.Users.AnyAsync(u => u.Username == username))
-            return (null, "Benutzername bereits vergeben.");
+            return (null, "Benutzername in dieser Firma bereits vergeben.");
 
         var (hash, salt) = HashPassword(password);
-        var user = new User { Username = username, PasswordHash = hash, PasswordSalt = salt };
+        var user = new User 
+        { 
+            Username = username, 
+            PasswordHash = hash, 
+            PasswordSalt = salt,
+            TenantId = tenantId.Value
+        };
         db.Users.Add(user);
         await db.SaveChangesAsync();
         await notifier.NotifyUsersChangedAsync();
         return (user, null);
     }
 
+    public async Task<(Tenant? Tenant, string? Error)> RegisterFirmAsync(RegisterFirmRequest req)
+    {
+        if (string.IsNullOrWhiteSpace(req.CompanyName) || req.CompanyName.Length < 3)
+            return (null, "Firmenname muss mindestens 3 Zeichen lang sein.");
+        if (string.IsNullOrWhiteSpace(req.Subdomain) || req.Subdomain.Length < 3)
+            return (null, "Subdomain muss mindestens 3 Zeichen lang sein.");
+        if (string.IsNullOrWhiteSpace(req.AdminUsername) || req.AdminUsername.Length < 3)
+            return (null, "Administrator-Benutzername muss mindestens 3 Zeichen lang sein.");
+        if (string.IsNullOrWhiteSpace(req.AdminPassword) || req.AdminPassword.Length < 6)
+            return (null, "Passwort muss mindestens 6 Zeichen lang sein.");
+
+        var subdomain = req.Subdomain.ToLower().Trim();
+        if (!subdomain.All(c => char.IsLetterOrDigit(c) || c == '-'))
+        {
+            return (null, "Subdomain darf nur Buchstaben, Zahlen und Bindestriche enthalten.");
+        }
+
+        var reservedSubdomains = new[] { "www", "api", "admin", "superadmin", "localhost", "mail", "portal", "app", "dev", "test" };
+        if (reservedSubdomains.Contains(subdomain))
+        {
+            return (null, "Diese Subdomain ist reserviert und kann nicht verwendet werden.");
+        }
+
+        await using var db = await factory.CreateDbContextAsync();
+        
+        // Tenant checks are global, no filters applied to Tenants table
+        var exists = await db.Tenants.AnyAsync(t => t.Subdomain == subdomain);
+        if (exists)
+        {
+            return (null, "Diese Subdomain ist bereits vergeben.");
+        }
+
+        await using var transaction = await db.Database.BeginTransactionAsync();
+        try
+        {
+            var tenant = new Tenant
+            {
+                Name = req.CompanyName,
+                Subdomain = subdomain,
+                IsApproved = false,
+                CreatedAt = DateTime.UtcNow
+            };
+            db.Tenants.Add(tenant);
+            await db.SaveChangesAsync();
+
+            var (hash, salt) = HashPassword(req.AdminPassword);
+            var user = new User
+            {
+                Username = req.AdminUsername,
+                PasswordHash = hash,
+                PasswordSalt = salt,
+                TenantId = tenant.Id,
+                IsTenantAdmin = true
+            };
+            db.Users.Add(user);
+            await db.SaveChangesAsync();
+
+            await transaction.CommitAsync();
+            
+            await notifier.NotifyUsersChangedAsync();
+            return (tenant, null);
+        }
+        catch (Exception ex)
+        {
+            await transaction.RollbackAsync();
+            return (null, $"Registrierungsfehler: {ex.Message}");
+        }
+    }
+
+    public async Task<string?> AssignTenantAsync(int userId, int? tenantId)
+    {
+        await using var db = await factory.CreateDbContextAsync();
+        
+        var user = await db.Users.IgnoreQueryFilters().FirstOrDefaultAsync(u => u.Id == userId);
+        if (user == null) return "Benutzer nicht gefunden.";
+
+        if (tenantId.HasValue)
+        {
+            var tenantExists = await db.Tenants.AnyAsync(t => t.Id == tenantId.Value);
+            if (!tenantExists) return "Firma existiert nicht.";
+        }
+
+        await using var transaction = await db.Database.BeginTransactionAsync();
+        try
+        {
+            user.TenantId = tenantId;
+
+            var settings = await db.AppSettings.IgnoreQueryFilters().Where(s => s.UserId == userId).ToListAsync();
+            foreach (var s in settings) s.TenantId = tenantId;
+
+            var workDays = await db.WorkDays.IgnoreQueryFilters().Where(w => w.UserId == userId).ToListAsync();
+            foreach (var w in workDays) w.TenantId = tenantId;
+
+            var vacationDays = await db.VacationDays.IgnoreQueryFilters().Where(v => v.UserId == userId).ToListAsync();
+            foreach (var v in vacationDays) v.TenantId = tenantId;
+
+            await db.SaveChangesAsync();
+            await transaction.CommitAsync();
+
+            await notifier.NotifyUsersChangedAsync();
+            return null;
+        }
+        catch (Exception ex)
+        {
+            await transaction.RollbackAsync();
+            return $"Fehler beim Verschieben des Benutzers: {ex.Message}";
+        }
+    }
+
+    public async Task<string?> ResetPasswordAsync(int userId, string newPassword)
+    {
+        if (string.IsNullOrWhiteSpace(newPassword) || newPassword.Length < 6)
+            return "Passwort muss mindestens 6 Zeichen lang sein.";
+
+        await using var db = await factory.CreateDbContextAsync();
+        var user = await db.Users.IgnoreQueryFilters().FirstOrDefaultAsync(u => u.Id == userId);
+        if (user == null) return "Benutzer nicht gefunden.";
+
+        var (hash, salt) = HashPassword(newPassword);
+        user.PasswordHash = hash;
+        user.PasswordSalt = salt;
+
+        await db.SaveChangesAsync();
+        return null;
+    }
+
     private static (string hash, string salt) HashPassword(string password)
     {
         var saltBytes = RandomNumberGenerator.GetBytes(32);

timetracker.Server/Data/ITenantProvider.cs

@@ -0,0 +1,10 @@
+using System.Threading.Tasks;
+using timetracker.Shared;
+
+namespace timetracker.Data;
+
+public interface ITenantProvider
+{
+    int? TenantId { get; }
+    Task<Tenant?> GetCurrentTenantAsync();
+}

timetracker.Server/Data/Migrations/20260624204954_AddMultiTenancy.Designer.cs

@@ -0,0 +1,254 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using timetracker.Data;
+
+#nullable disable
+
+namespace timetracker.Data.Migrations
+{
+    [DbContext(typeof(TimetrackerDbContext))]
+    [Migration("20260624204954_AddMultiTenancy")]
+    partial class AddMultiTenancy
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder.HasAnnotation("ProductVersion", "10.0.8");
+
+            modelBuilder.Entity("timetracker.Shared.AppSettings", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<double>("DailyTargetHours")
+                        .HasColumnType("REAL");
+
+                    b.Property<DateOnly?>("FlexTimeStartDate")
+                        .HasColumnType("TEXT");
+
+                    b.Property<double>("FlexTimeStartingBalanceHours")
+                        .HasColumnType("REAL");
+
+                    b.Property<string>("GermanState")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("MinimumBreakMinutes")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("VacationDaysPerYear")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkFriday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkMonday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkSaturday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkSunday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkThursday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkTuesday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkWednesday")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("AppSettings");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.BreakEntry", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<TimeOnly?>("EndTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("StartTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("WorkDayId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("WorkDayId");
+
+                    b.ToTable("BreakEntries");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.PublicHoliday", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Counties")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("PublicHolidays");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.Tenant", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<bool>("IsApproved")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Subdomain")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Subdomain")
+                        .IsUnique();
+
+                    b.ToTable("Tenants");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.User", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("PasswordSalt")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TenantId");
+
+                    b.ToTable("Users");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.VacationDay", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Note")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("VacationDays");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.WorkDay", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("EndTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("StartTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("WorkDays");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.BreakEntry", b =>
+                {
+                    b.HasOne("timetracker.Shared.WorkDay", "WorkDay")
+                        .WithMany("Breaks")
+                        .HasForeignKey("WorkDayId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("WorkDay");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.User", b =>
+                {
+                    b.HasOne("timetracker.Shared.Tenant", "Tenant")
+                        .WithMany()
+                        .HasForeignKey("TenantId");
+
+                    b.Navigation("Tenant");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.WorkDay", b =>
+                {
+                    b.Navigation("Breaks");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

timetracker.Server/Data/Migrations/20260624204954_AddMultiTenancy.cs

@@ -0,0 +1,104 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace timetracker.Data.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddMultiTenancy : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<int>(
+                name: "TenantId",
+                table: "WorkDays",
+                type: "INTEGER",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "TenantId",
+                table: "VacationDays",
+                type: "INTEGER",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "TenantId",
+                table: "Users",
+                type: "INTEGER",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "TenantId",
+                table: "AppSettings",
+                type: "INTEGER",
+                nullable: true);
+
+            migrationBuilder.CreateTable(
+                name: "Tenants",
+                columns: table => new
+                {
+                    Id = table.Column<int>(type: "INTEGER", nullable: false)
+                        .Annotation("Sqlite:Autoincrement", true),
+                    Name = table.Column<string>(type: "TEXT", nullable: false),
+                    Subdomain = table.Column<string>(type: "TEXT", nullable: false),
+                    IsApproved = table.Column<bool>(type: "INTEGER", nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "TEXT", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_Tenants", x => x.Id);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Users_TenantId",
+                table: "Users",
+                column: "TenantId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Tenants_Subdomain",
+                table: "Tenants",
+                column: "Subdomain",
+                unique: true);
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_Users_Tenants_TenantId",
+                table: "Users",
+                column: "TenantId",
+                principalTable: "Tenants",
+                principalColumn: "Id");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_Users_Tenants_TenantId",
+                table: "Users");
+
+            migrationBuilder.DropTable(
+                name: "Tenants");
+
+            migrationBuilder.DropIndex(
+                name: "IX_Users_TenantId",
+                table: "Users");
+
+            migrationBuilder.DropColumn(
+                name: "TenantId",
+                table: "WorkDays");
+
+            migrationBuilder.DropColumn(
+                name: "TenantId",
+                table: "VacationDays");
+
+            migrationBuilder.DropColumn(
+                name: "TenantId",
+                table: "Users");
+
+            migrationBuilder.DropColumn(
+                name: "TenantId",
+                table: "AppSettings");
+        }
+    }
+}

timetracker.Server/Data/Migrations/20260624210436_AddTenantBranding.Designer.cs

@@ -0,0 +1,265 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using timetracker.Data;
+
+#nullable disable
+
+namespace timetracker.Data.Migrations
+{
+    [DbContext(typeof(TimetrackerDbContext))]
+    [Migration("20260624210436_AddTenantBranding")]
+    partial class AddTenantBranding
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder.HasAnnotation("ProductVersion", "10.0.8");
+
+            modelBuilder.Entity("timetracker.Shared.AppSettings", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<double>("DailyTargetHours")
+                        .HasColumnType("REAL");
+
+                    b.Property<DateOnly?>("FlexTimeStartDate")
+                        .HasColumnType("TEXT");
+
+                    b.Property<double>("FlexTimeStartingBalanceHours")
+                        .HasColumnType("REAL");
+
+                    b.Property<string>("GermanState")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("MinimumBreakMinutes")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("VacationDaysPerYear")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkFriday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkMonday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkSaturday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkSunday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkThursday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkTuesday")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("WorkWednesday")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("AppSettings");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.BreakEntry", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<TimeOnly?>("EndTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("StartTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("WorkDayId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("WorkDayId");
+
+                    b.ToTable("BreakEntries");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.PublicHoliday", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Counties")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("PublicHolidays");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.Tenant", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<bool>("IsApproved")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("PrimaryColor")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("SecondaryColor")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Subdomain")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Subdomain")
+                        .IsUnique();
+
+                    b.ToTable("Tenants");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.User", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("IsTenantAdmin")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("PasswordSalt")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TenantId");
+
+                    b.ToTable("Users");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.VacationDay", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Note")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("VacationDays");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.WorkDay", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("EndTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<TimeOnly?>("StartTime")
+                        .HasColumnType("TEXT");
+
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("WorkDays");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.BreakEntry", b =>
+                {
+                    b.HasOne("timetracker.Shared.WorkDay", "WorkDay")
+                        .WithMany("Breaks")
+                        .HasForeignKey("WorkDayId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("WorkDay");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.User", b =>
+                {
+                    b.HasOne("timetracker.Shared.Tenant", "Tenant")
+                        .WithMany()
+                        .HasForeignKey("TenantId");
+
+                    b.Navigation("Tenant");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.WorkDay", b =>
+                {
+                    b.Navigation("Breaks");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

timetracker.Server/Data/Migrations/20260624210436_AddTenantBranding.cs

@@ -0,0 +1,51 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace timetracker.Data.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddTenantBranding : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<bool>(
+                name: "IsTenantAdmin",
+                table: "Users",
+                type: "INTEGER",
+                nullable: false,
+                defaultValue: false);
+
+            migrationBuilder.AddColumn<string>(
+                name: "PrimaryColor",
+                table: "Tenants",
+                type: "TEXT",
+                nullable: false,
+                defaultValue: "");
+
+            migrationBuilder.AddColumn<string>(
+                name: "SecondaryColor",
+                table: "Tenants",
+                type: "TEXT",
+                nullable: false,
+                defaultValue: "");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "IsTenantAdmin",
+                table: "Users");
+
+            migrationBuilder.DropColumn(
+                name: "PrimaryColor",
+                table: "Tenants");
+
+            migrationBuilder.DropColumn(
+                name: "SecondaryColor",
+                table: "Tenants");
+        }
+    }
+}

timetracker.Server/Data/Migrations/TimetrackerDbContextModelSnapshot.cs

@@ -17,7 +17,7 @@ namespace timetracker.Data.Migrations
 #pragma warning disable 612, 618
             modelBuilder.HasAnnotation("ProductVersion", "10.0.8");
 
-            modelBuilder.Entity("timetracker.Data.AppSettings", b =>
+            modelBuilder.Entity("timetracker.Shared.AppSettings", b =>
                 {
                     b.Property<int>("Id")
                         .ValueGeneratedOnAdd()
@@ -38,6 +38,9 @@ namespace timetracker.Data.Migrations
                     b.Property<int>("MinimumBreakMinutes")
                         .HasColumnType("INTEGER");
 
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
                     b.Property<int>("UserId")
                         .HasColumnType("INTEGER");
 
@@ -70,7 +73,7 @@ namespace timetracker.Data.Migrations
                     b.ToTable("AppSettings");
                 });
 
-            modelBuilder.Entity("timetracker.Data.BreakEntry", b =>
+            modelBuilder.Entity("timetracker.Shared.BreakEntry", b =>
                 {
                     b.Property<int>("Id")
                         .ValueGeneratedOnAdd()
@@ -92,7 +95,7 @@ namespace timetracker.Data.Migrations
                     b.ToTable("BreakEntries");
                 });
 
-            modelBuilder.Entity("timetracker.Data.PublicHoliday", b =>
+            modelBuilder.Entity("timetracker.Shared.PublicHoliday", b =>
                 {
                     b.Property<int>("Id")
                         .ValueGeneratedOnAdd()
@@ -113,12 +116,51 @@ namespace timetracker.Data.Migrations
                     b.ToTable("PublicHolidays");
                 });
 
-            modelBuilder.Entity("timetracker.Data.User", b =>
+            modelBuilder.Entity("timetracker.Shared.Tenant", b =>
                 {
                     b.Property<int>("Id")
                         .ValueGeneratedOnAdd()
                         .HasColumnType("INTEGER");
 
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT");
+
+                    b.Property<bool>("IsApproved")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("PrimaryColor")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("SecondaryColor")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Subdomain")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Subdomain")
+                        .IsUnique();
+
+                    b.ToTable("Tenants");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.User", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("IsTenantAdmin")
+                        .HasColumnType("INTEGER");
+
                     b.Property<string>("PasswordHash")
                         .IsRequired()
                         .HasColumnType("TEXT");
@@ -127,16 +169,21 @@ namespace timetracker.Data.Migrations
                         .IsRequired()
                         .HasColumnType("TEXT");
 
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
                     b.Property<string>("Username")
                         .IsRequired()
                         .HasColumnType("TEXT");
 
                     b.HasKey("Id");
 
+                    b.HasIndex("TenantId");
+
                     b.ToTable("Users");
                 });
 
-            modelBuilder.Entity("timetracker.Data.VacationDay", b =>
+            modelBuilder.Entity("timetracker.Shared.VacationDay", b =>
                 {
                     b.Property<int>("Id")
                         .ValueGeneratedOnAdd()
@@ -148,6 +195,9 @@ namespace timetracker.Data.Migrations
                     b.Property<string>("Note")
                         .HasColumnType("TEXT");
 
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
                     b.Property<int>("UserId")
                         .HasColumnType("INTEGER");
 
@@ -156,7 +206,7 @@ namespace timetracker.Data.Migrations
                     b.ToTable("VacationDays");
                 });
 
-            modelBuilder.Entity("timetracker.Data.WorkDay", b =>
+            modelBuilder.Entity("timetracker.Shared.WorkDay", b =>
                 {
                     b.Property<int>("Id")
                         .ValueGeneratedOnAdd()
@@ -171,6 +221,9 @@ namespace timetracker.Data.Migrations
                     b.Property<TimeOnly?>("StartTime")
                         .HasColumnType("TEXT");
 
+                    b.Property<int?>("TenantId")
+                        .HasColumnType("INTEGER");
+
                     b.Property<int>("UserId")
                         .HasColumnType("INTEGER");
 
@@ -179,9 +232,9 @@ namespace timetracker.Data.Migrations
                     b.ToTable("WorkDays");
                 });
 
-            modelBuilder.Entity("timetracker.Data.BreakEntry", b =>
+            modelBuilder.Entity("timetracker.Shared.BreakEntry", b =>
                 {
-                    b.HasOne("timetracker.Data.WorkDay", "WorkDay")
+                    b.HasOne("timetracker.Shared.WorkDay", "WorkDay")
                         .WithMany("Breaks")
                         .HasForeignKey("WorkDayId")
                         .OnDelete(DeleteBehavior.Cascade)
@@ -190,7 +243,16 @@ namespace timetracker.Data.Migrations
                     b.Navigation("WorkDay");
                 });
 
-            modelBuilder.Entity("timetracker.Data.WorkDay", b =>
+            modelBuilder.Entity("timetracker.Shared.User", b =>
+                {
+                    b.HasOne("timetracker.Shared.Tenant", "Tenant")
+                        .WithMany()
+                        .HasForeignKey("TenantId");
+
+                    b.Navigation("Tenant");
+                });
+
+            modelBuilder.Entity("timetracker.Shared.WorkDay", b =>
                 {
                     b.Navigation("Breaks");
                 });

timetracker.Server/Data/TenantProvider.cs

@@ -0,0 +1,126 @@
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Configuration;
+using timetracker.Shared;
+
+namespace timetracker.Data;
+
+public class TenantProvider : ITenantProvider
+{
+    private readonly IHttpContextAccessor _httpContextAccessor;
+    private readonly IDbContextFactory<TimetrackerDbContext> _dbContextFactory;
+    private readonly IConfiguration _configuration;
+
+    public TenantProvider(
+        IHttpContextAccessor httpContextAccessor,
+        IDbContextFactory<TimetrackerDbContext> dbContextFactory,
+        IConfiguration configuration)
+    {
+        _httpContextAccessor = httpContextAccessor;
+        _dbContextFactory = dbContextFactory;
+        _configuration = configuration;
+    }
+
+    public int? TenantId
+    {
+        get
+        {
+            var httpContext = _httpContextAccessor.HttpContext;
+            if (httpContext == null) return null;
+
+            if (httpContext.Items.TryGetValue("TenantId", out var cachedId))
+            {
+                return (int?)cachedId;
+            }
+
+            // Resolve and cache in HttpContext.Items
+            ResolveTenantAsync().GetAwaiter().GetResult();
+
+            if (httpContext.Items.TryGetValue("TenantId", out cachedId))
+            {
+                return (int?)cachedId;
+            }
+
+            return null;
+        }
+    }
+
+    public async Task<Tenant?> GetCurrentTenantAsync()
+    {
+        var httpContext = _httpContextAccessor.HttpContext;
+        if (httpContext == null) return null;
+
+        if (httpContext.Items.TryGetValue("CurrentTenant", out var cachedTenant))
+        {
+            return (Tenant?)cachedTenant;
+        }
+
+        await ResolveTenantAsync();
+
+        if (httpContext.Items.TryGetValue("CurrentTenant", out cachedTenant))
+        {
+            return (Tenant?)cachedTenant;
+        }
+
+        return null;
+    }
+
+    private async Task ResolveTenantAsync()
+    {
+        var httpContext = _httpContextAccessor.HttpContext;
+        if (httpContext == null) return;
+
+        // Prevent double resolution in the same request
+        if (httpContext.Items.ContainsKey("TenantResolved")) return;
+        httpContext.Items["TenantResolved"] = true;
+
+        var host = httpContext.Request.Host.Host;
+        var subdomain = GetSubdomain(host);
+
+        if (!string.IsNullOrEmpty(subdomain))
+        {
+            await using var db = await _dbContextFactory.CreateDbContextAsync();
+            var tenant = await db.Tenants
+                .FirstOrDefaultAsync(t => t.Subdomain.ToLower() == subdomain.ToLower());
+
+            if (tenant != null)
+            {
+                httpContext.Items["CurrentTenant"] = tenant;
+                httpContext.Items["TenantId"] = tenant.Id;
+            }
+        }
+    }
+
+    private string? GetSubdomain(string host)
+    {
+        var baseDomain = _configuration["TenantSettings:BaseDomain"] ?? "localhost";
+
+        // Ignore port if included in host
+        var hostName = host.Split(':')[0];
+
+        if (hostName.Equals(baseDomain, StringComparison.OrdinalIgnoreCase))
+        {
+            return null; // Main domain
+        }
+
+        if (hostName.EndsWith("." + baseDomain, StringComparison.OrdinalIgnoreCase))
+        {
+            return hostName.Substring(0, hostName.Length - baseDomain.Length - 1);
+        }
+
+        // Fallback for localhost testing
+        if (baseDomain.Equals("localhost", StringComparison.OrdinalIgnoreCase))
+        {
+            var parts = hostName.Split('.');
+            if (parts.Length > 1 && !hostName.Equals("localhost", StringComparison.OrdinalIgnoreCase))
+            {
+                return parts[0];
+            }
+        }
+
+        return null;
+    }
+}

timetracker.Server/Data/TimetrackerDbContext.cs

@@ -1,14 +1,72 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
 using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
 using timetracker.Shared;
 
 namespace timetracker.Data;
 
-public class TimetrackerDbContext(DbContextOptions<TimetrackerDbContext> options) : DbContext(options)
+public class TimetrackerDbContext : DbContext
 {
+    private readonly IServiceProvider _serviceProvider;
+    private ITenantProvider? _tenantProvider;
+    private ITenantProvider TenantProvider => _tenantProvider ??= _serviceProvider.GetRequiredService<ITenantProvider>();
+
+    public TimetrackerDbContext(
+        DbContextOptions<TimetrackerDbContext> options,
+        IServiceProvider serviceProvider) : base(options)
+    {
+        _serviceProvider = serviceProvider;
+    }
+
+    public DbSet<Tenant> Tenants => Set<Tenant>();
     public DbSet<User> Users => Set<User>();
     public DbSet<WorkDay> WorkDays => Set<WorkDay>();
     public DbSet<BreakEntry> BreakEntries => Set<BreakEntry>();
     public DbSet<AppSettings> AppSettings => Set<AppSettings>();
     public DbSet<VacationDay> VacationDays => Set<VacationDay>();
     public DbSet<PublicHoliday> PublicHolidays => Set<PublicHoliday>();
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        base.OnModelCreating(modelBuilder);
+
+        // Subdomain index unique
+        modelBuilder.Entity<Tenant>()
+            .HasIndex(t => t.Subdomain)
+            .IsUnique();
+
+        // Global Query Filters (scopes database views by resolved TenantId)
+        modelBuilder.Entity<User>().HasQueryFilter(u => u.TenantId == TenantProvider.TenantId);
+        modelBuilder.Entity<WorkDay>().HasQueryFilter(w => w.TenantId == TenantProvider.TenantId);
+        modelBuilder.Entity<VacationDay>().HasQueryFilter(v => v.TenantId == TenantProvider.TenantId);
+        modelBuilder.Entity<AppSettings>().HasQueryFilter(s => s.TenantId == TenantProvider.TenantId);
+    }
+
+    public override Task<int> SaveChangesAsync(CancellationToken cancellationToken = default)
+    {
+        var tenantId = TenantProvider.TenantId;
+
+        if (tenantId.HasValue)
+        {
+            foreach (var entry in ChangeTracker.Entries())
+            {
+                if (entry.State == EntityState.Added)
+                {
+                    var tenantIdProp = entry.Entity.GetType().GetProperty("TenantId");
+                    if (tenantIdProp != null && tenantIdProp.CanWrite)
+                    {
+                        var currentValue = tenantIdProp.GetValue(entry.Entity);
+                        if (currentValue == null || (currentValue is int val && val == 0))
+                        {
+                            tenantIdProp.SetValue(entry.Entity, tenantId.Value);
+                        }
+                    }
+                }
+            }
+        }
+
+        return base.SaveChangesAsync(cancellationToken);
+    }
 }

timetracker.Server/Program.cs

@@ -47,6 +47,8 @@ builder.Services.AddAuthorization(options =>
 builder.Services.AddCascadingAuthenticationState();
 builder.Services.AddHttpContextAccessor();
 
+builder.Services.AddTransient<ITenantProvider, TenantProvider>();
+
 // Add SignalR
 builder.Services.AddSignalR();
 builder.Services.AddSingleton<UserNotificationService>();
@@ -63,6 +65,31 @@ builder.Services.AddRazorComponents()
 
 builder.Services.AddMudServices();
 builder.Services.AddHttpClient<HolidayService>();
+builder.Services.AddScoped(sp =>
+{
+    try
+    {
+        var navigationManager = sp.GetService<Microsoft.AspNetCore.Components.NavigationManager>();
+        if (navigationManager != null && !string.IsNullOrEmpty(navigationManager.BaseUri))
+        {
+            return new System.Net.Http.HttpClient { BaseAddress = new Uri(navigationManager.BaseUri) };
+        }
+    }
+    catch (InvalidOperationException)
+    {
+        // NavigationManager is registered but not initialized in this request scope
+    }
+    
+    var httpContextAccessor = sp.GetService<Microsoft.AspNetCore.Http.IHttpContextAccessor>();
+    var request = httpContextAccessor?.HttpContext?.Request;
+    if (request != null)
+    {
+        var baseUri = $"{request.Scheme}://{request.Host}{request.PathBase}/";
+        return new System.Net.Http.HttpClient { BaseAddress = new Uri(baseUri) };
+    }
+    
+    return new System.Net.Http.HttpClient();
+});
 
 builder.Services.AddRateLimiter(options =>
 {
@@ -162,54 +189,93 @@ app.MapGet("/api/auth/me", (HttpContext ctx) =>
     {
         var idClaim = ctx.User.FindFirst(ClaimTypes.NameIdentifier)?.Value;
         var name = ctx.User.Identity.Name ?? "";
+        var isTenantAdmin = ctx.User.FindFirst("IsTenantAdmin")?.Value == "true";
         if (int.TryParse(idClaim, out var id))
         {
-            return Results.Ok(new UserInfo { Id = id, Username = name });
+            return Results.Ok(new UserInfo { Id = id, Username = name, IsTenantAdmin = isTenantAdmin });
         }
     }
     return Results.Unauthorized();
 });
 
-app.MapPost("/api/auth/login", async (HttpContext ctx, [FromBody] LoginRequest req, IAuthService authService) =>
+app.MapPost("/api/auth/login", async (HttpContext ctx, [FromBody] LoginRequest req, IAuthService authService, ITenantProvider tenantProvider) =>
 {
+    var tenant = await tenantProvider.GetCurrentTenantAsync();
+    if (tenant != null && !tenant.IsApproved)
+    {
+        return Results.BadRequest("Diese Firma ist noch nicht freigeschaltet.");
+    }
+
     var user = await authService.LoginAsync(req.Username, req.Password);
     if (user == null)
         return Results.BadRequest("Benutzername oder Passwort falsch.");
 
-    var claims = new[] {
+    if (tenant != null)
+    {
+        if (user.TenantId != tenant.Id)
+        {
+            return Results.BadRequest("Benutzer gehört nicht zu dieser Firma.");
+        }
+    }
+    else
+    {
+        if (user.Username != "marc")
+        {
+            return Results.BadRequest("Anmeldung auf der Hauptdomain nur für Administratoren.");
+        }
+    }
+
+    var claims = new List<Claim> {
         new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
-        new Claim(ClaimTypes.Name, user.Username)
+        new Claim(ClaimTypes.Name, user.Username),
+        new Claim("IsTenantAdmin", user.IsTenantAdmin ? "true" : "false")
     };
+    if (user.TenantId.HasValue)
+    {
+        claims.Add(new Claim("TenantId", user.TenantId.Value.ToString()));
+    }
+
     var identity = new ClaimsIdentity(claims, CookieAuthenticationDefaults.AuthenticationScheme);
     await ctx.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme,
         new ClaimsPrincipal(identity),
         new AuthenticationProperties { IsPersistent = true });
 
-    return Results.Ok(new UserInfo { Id = user.Id, Username = user.Username });
+    return Results.Ok(new UserInfo { Id = user.Id, Username = user.Username, IsTenantAdmin = user.IsTenantAdmin });
 }).RequireRateLimiting("auth-limit");
 
-app.MapPost("/api/auth/register", async (HttpContext ctx, [FromBody] RegisterRequest req, IAuthService authService) =>
+app.MapPost("/api/auth/register", async (HttpContext ctx, [FromBody] RegisterRequest req, IAuthService authService, ITenantProvider tenantProvider) =>
 {
     if (!string.IsNullOrEmpty(req.Honeypot))
     {
-        // Silently reject bots
         return Results.BadRequest("Registrierung fehlgeschlagen.");
     }
 
+    var tenant = await tenantProvider.GetCurrentTenantAsync();
+    if (tenant != null && !tenant.IsApproved)
+    {
+        return Results.BadRequest("Registrierung blockiert: Firma noch nicht freigeschaltet.");
+    }
+
     var (user, error) = await authService.RegisterAsync(req.Username, req.Password);
     if (user == null)
         return Results.BadRequest(error ?? "Registrierung fehlgeschlagen.");
 
-    var claims = new[] {
+    var claims = new List<Claim> {
         new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
-        new Claim(ClaimTypes.Name, user.Username)
+        new Claim(ClaimTypes.Name, user.Username),
+        new Claim("IsTenantAdmin", user.IsTenantAdmin ? "true" : "false")
     };
+    if (user.TenantId.HasValue)
+    {
+        claims.Add(new Claim("TenantId", user.TenantId.Value.ToString()));
+    }
+
     var identity = new ClaimsIdentity(claims, CookieAuthenticationDefaults.AuthenticationScheme);
     await ctx.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme,
         new ClaimsPrincipal(identity),
         new AuthenticationProperties { IsPersistent = true });
 
-    return Results.Ok(new UserInfo { Id = user.Id, Username = user.Username });
+    return Results.Ok(new UserInfo { Id = user.Id, Username = user.Username, IsTenantAdmin = user.IsTenantAdmin });
 }).RequireRateLimiting("auth-limit");
 
 app.MapGet("/auth/logout", async (HttpContext ctx) =>
@@ -253,9 +319,57 @@ usersApi.MapPut("/{userId:int}/change-password", async (int userId, [FromBody] C
     return Results.Ok();
 });
 
+usersApi.MapPut("/{userId:int}/assign-tenant", async (int userId, [FromBody] AssignTenantRequest req, IAuthService authService) =>
+{
+    var error = await authService.AssignTenantAsync(userId, req.TenantId);
+    if (error != null)
+    {
+        return Results.BadRequest(error);
+    }
+    return Results.Ok();
+});
+
+usersApi.MapPut("/{userId:int}/reset-password", async (int userId, [FromBody] ResetPasswordRequest req, IAuthService authService) =>
+{
+    var error = await authService.ResetPasswordAsync(userId, req.NewPassword);
+    if (error != null)
+    {
+        return Results.BadRequest(error);
+    }
+    return Results.Ok();
+});
+
 // ── Timetracker-API-Endpoints (Protected) ─────────────────────────────────────
 var trackerApi = app.MapGroup("/api/tracker").RequireAuthorization();
 
+trackerApi.MapPost("/tenant/settings", async (ClaimsPrincipal claimsPrincipal, [FromBody] TenantSettingsDto dto, ITenantProvider tenantProvider, TimetrackerDbContext db) =>
+{
+    var isAdmin = claimsPrincipal.FindFirst("IsTenantAdmin")?.Value == "true";
+    if (!isAdmin) return Results.Forbid();
+
+    var tenant = await tenantProvider.GetCurrentTenantAsync();
+    if (tenant == null) return Results.BadRequest("Keine Firma aktiv.");
+
+    var dbTenant = await db.Tenants.FindAsync(tenant.Id);
+    if (dbTenant == null) return Results.NotFound("Firma nicht gefunden.");
+
+    if (!string.IsNullOrWhiteSpace(dto.Name))
+    {
+        dbTenant.Name = dto.Name.Trim();
+    }
+    if (!string.IsNullOrWhiteSpace(dto.PrimaryColor))
+    {
+        dbTenant.PrimaryColor = dto.PrimaryColor.Trim();
+    }
+    if (!string.IsNullOrWhiteSpace(dto.SecondaryColor))
+    {
+        dbTenant.SecondaryColor = dto.SecondaryColor.Trim();
+    }
+
+    await db.SaveChangesAsync();
+    return Results.Ok();
+});
+
 trackerApi.MapGet("/week", async (ClaimsPrincipal claimsPrincipal, [FromQuery] string monday, ITimetrackerService trackerService) =>
 {
     var idClaim = claimsPrincipal.FindFirst(ClaimTypes.NameIdentifier)?.Value;
@@ -366,6 +480,130 @@ holidaysApi.MapDelete("/{id:int}", async (int id, IHolidayService holidayService
     return Results.NoContent();
 });
 
+app.MapGet("/api/tenant/current", async (ITenantProvider tenantProvider) =>
+{
+    var tenant = await tenantProvider.GetCurrentTenantAsync();
+    if (tenant == null)
+    {
+        return Results.Ok(new TenantInfo { IsTenant = false });
+    }
+    return Results.Ok(new TenantInfo
+    {
+        IsTenant = true,
+        Name = tenant.Name,
+        Subdomain = tenant.Subdomain,
+        IsApproved = tenant.IsApproved,
+        PrimaryColor = tenant.PrimaryColor,
+        SecondaryColor = tenant.SecondaryColor
+    });
+});
+
+app.MapPost("/api/auth/register-firm", async ([FromBody] RegisterFirmRequest req, IAuthService authService) =>
+{
+    var (tenant, error) = await authService.RegisterFirmAsync(req);
+    if (tenant == null)
+        return Results.BadRequest(error ?? "Registrierung der Firma fehlgeschlagen.");
+
+    return Results.Ok(new { Success = true });
+}).RequireRateLimiting("auth-limit");
+
+// ── SuperAdmin-API-Endpoints (Protected) ───────────────────────────────────────────
+var superAdminApi = app.MapGroup("/api/superadmin").RequireAuthorization("AdminOnly");
+
+superAdminApi.MapGet("/tenants", async (TimetrackerDbContext db) =>
+{
+    var tenants = await db.Tenants
+        .OrderByDescending(t => t.CreatedAt)
+        .ToListAsync();
+
+    var stats = new List<object>();
+    foreach (var t in tenants)
+    {
+        var userCount = await db.Users.IgnoreQueryFilters().CountAsync(u => u.TenantId == t.Id);
+        var workDaysCount = await db.WorkDays.IgnoreQueryFilters().CountAsync(w => w.TenantId == t.Id);
+        var tenantUsers = await db.Users.IgnoreQueryFilters()
+            .Where(u => u.TenantId == t.Id)
+            .Select(u => new { u.Id, u.Username, u.IsTenantAdmin })
+            .ToListAsync();
+
+        stats.Add(new
+        {
+            t.Id,
+            t.Name,
+            t.Subdomain,
+            t.IsApproved,
+            t.CreatedAt,
+            UserCount = userCount,
+            WorkDaysCount = workDaysCount,
+            Users = tenantUsers
+        });
+    }
+    return Results.Ok(stats);
+});
+
+superAdminApi.MapPost("/tenants/{id:int}/approve", async (int id, TimetrackerDbContext db) =>
+{
+    var tenant = await db.Tenants.FindAsync(id);
+    if (tenant == null) return Results.NotFound();
+    tenant.IsApproved = true;
+    await db.SaveChangesAsync();
+    return Results.Ok();
+});
+
+superAdminApi.MapPost("/tenants/{id:int}/toggle-active", async (int id, TimetrackerDbContext db) =>
+{
+    var tenant = await db.Tenants.FindAsync(id);
+    if (tenant == null) return Results.NotFound();
+    tenant.IsApproved = !tenant.IsApproved;
+    await db.SaveChangesAsync();
+    return Results.Ok();
+});
+
+superAdminApi.MapDelete("/tenants/{id:int}", async (int id, TimetrackerDbContext db, UserNotificationService notifier) =>
+{
+    var tenant = await db.Tenants.FindAsync(id);
+    if (tenant == null) return Results.NotFound();
+
+    await using var transaction = await db.Database.BeginTransactionAsync();
+    try
+    {
+        var userIds = await db.Users.IgnoreQueryFilters()
+            .Where(u => u.TenantId == id)
+            .Select(u => u.Id)
+            .ToListAsync();
+
+        var workDays = await db.WorkDays.IgnoreQueryFilters().Where(w => w.TenantId == id).ToListAsync();
+        db.WorkDays.RemoveRange(workDays);
+
+        var vacationDays = await db.VacationDays.IgnoreQueryFilters().Where(v => v.TenantId == id).ToListAsync();
+        db.VacationDays.RemoveRange(vacationDays);
+
+        var settings = await db.AppSettings.IgnoreQueryFilters().Where(s => s.TenantId == id).ToListAsync();
+        db.AppSettings.RemoveRange(settings);
+
+        var users = await db.Users.IgnoreQueryFilters().Where(u => u.TenantId == id).ToListAsync();
+        db.Users.RemoveRange(users);
+
+        db.Tenants.Remove(tenant);
+
+        await db.SaveChangesAsync();
+        await transaction.CommitAsync();
+
+        foreach (var uid in userIds)
+        {
+            await notifier.NotifyUserDeletedAsync(uid);
+        }
+        await notifier.NotifyUsersChangedAsync();
+
+        return Results.NoContent();
+    }
+    catch (Exception ex)
+    {
+        await transaction.RollbackAsync();
+        return Results.BadRequest($"Fehler beim Löschen der Firma: {ex.Message}");
+    }
+});
+
 app.Run();
 
 // ── Models for Request Bodies ──────────────────────────────────────────────────

timetracker.Shared/AppSettings.cs

@@ -4,6 +4,7 @@ public class AppSettings
 {
     public int Id { get; set; }
     public int UserId { get; set; }
+    public int? TenantId { get; set; }
     public double DailyTargetHours { get; set; } = 7.5;
     public int MinimumBreakMinutes { get; set; } = 30;
     public int VacationDaysPerYear { get; set; } = 30;

timetracker.Shared/AssignTenantRequest.cs

@@ -0,0 +1,3 @@
+namespace timetracker.Shared;
+
+public record AssignTenantRequest(int? TenantId);

timetracker.Shared/IAuthService.cs

@@ -8,4 +8,7 @@ public interface IAuthService
     Task<string?> RenameUserAsync(int userId, string newUsername);
     Task<string?> ChangePasswordAsync(int userId, string currentPassword, string newPassword);
     Task<(User? User, string? Error)> RegisterAsync(string username, string password, string? honeypot = null);
+    Task<(Tenant? Tenant, string? Error)> RegisterFirmAsync(RegisterFirmRequest req);
+    Task<string?> AssignTenantAsync(int userId, int? tenantId);
+    Task<string?> ResetPasswordAsync(int userId, string newPassword);
 }

timetracker.Shared/RegisterFirmRequest.cs

@@ -0,0 +1,8 @@
+namespace timetracker.Shared;
+
+public record RegisterFirmRequest(
+    string CompanyName,
+    string Subdomain,
+    string AdminUsername,
+    string AdminPassword
+);

timetracker.Shared/ResetPasswordRequest.cs

@@ -0,0 +1,3 @@
+namespace timetracker.Shared;
+
+public record ResetPasswordRequest(string NewPassword);

timetracker.Shared/Tenant.cs

@@ -0,0 +1,14 @@
+using System;
+
+namespace timetracker.Shared;
+
+public class Tenant
+{
+    public int Id { get; set; }
+    public string Name { get; set; } = "";
+    public string Subdomain { get; set; } = "";
+    public bool IsApproved { get; set; }
+    public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
+    public string PrimaryColor { get; set; } = "#0EA5E9";
+    public string SecondaryColor { get; set; } = "#0EA5E9";
+}

timetracker.Shared/TenantInfo.cs

@@ -0,0 +1,11 @@
+namespace timetracker.Shared;
+
+public class TenantInfo
+{
+    public bool IsTenant { get; set; }
+    public string? Name { get; set; }
+    public string? Subdomain { get; set; }
+    public bool IsApproved { get; set; }
+    public string? PrimaryColor { get; set; }
+    public string? SecondaryColor { get; set; }
+}

timetracker.Shared/TenantSettingsDto.cs

@@ -0,0 +1,8 @@
+namespace timetracker.Shared;
+
+public class TenantSettingsDto
+{
+    public string Name { get; set; } = "";
+    public string PrimaryColor { get; set; } = "#0EA5E9";
+    public string SecondaryColor { get; set; } = "#0EA5E9";
+}

timetracker.Shared/TenantStats.cs

@@ -0,0 +1,23 @@
+using System;
+
+namespace timetracker.Shared;
+
+public class TenantStats
+{
+    public int Id { get; set; }
+    public string Name { get; set; } = "";
+    public string Subdomain { get; set; } = "";
+    public bool IsApproved { get; set; }
+    public DateTime CreatedAt { get; set; }
+    public int UserCount { get; set; }
+    public int WorkDaysCount { get; set; }
+    public List<TenantUserDto> Users { get; set; } = new();
+    public bool ShowDetails { get; set; }
+}
+
+public class TenantUserDto
+{
+    public int Id { get; set; }
+    public string Username { get; set; } = "";
+    public bool IsTenantAdmin { get; set; }
+}

timetracker.Shared/User.cs

@@ -6,4 +6,8 @@ public class User
     public string Username { get; set; } = "";
     public string PasswordHash { get; set; } = "";
     public string PasswordSalt { get; set; } = "";
+    
+    public int? TenantId { get; set; }
+    public Tenant? Tenant { get; set; }
+    public bool IsTenantAdmin { get; set; }
 }

timetracker.Shared/UserInfo.cs

@@ -4,4 +4,5 @@ public class UserInfo
 {
     public int Id { get; set; }
     public string Username { get; set; } = "";
+    public bool IsTenantAdmin { get; set; }
 }

timetracker.Shared/VacationDay.cs

@@ -4,6 +4,7 @@ public class VacationDay
 {
     public int Id { get; set; }
     public int UserId { get; set; }
+    public int? TenantId { get; set; }
     public DateOnly Date { get; set; }
     public string? Note { get; set; }
 }

timetracker.Shared/WorkDay.cs

@@ -4,6 +4,7 @@ public class WorkDay
 {
     public int Id { get; set; }
     public int UserId { get; set; }
+    public int? TenantId { get; set; }
     public DateOnly Date { get; set; }
     public TimeOnly? StartTime { get; set; }
     public TimeOnly? EndTime { get; set; }

todo.md

@@ -0,0 +1,4 @@
+# TODOs für morgen
+
+- [ ] **Single-User-Variante bauen:** Eine Möglichkeit implementieren, sich einfach und unabhängig von einem bestimmten Tenant zu registrieren.
+- [ ] **Pricing-Modell konzipieren:** Gedanken über ein geeignetes Preismodell machen (z. B. SaaS-Preise, Mandanten-Preismodell).