Implement complete frontend with admin panel and theme system

- Add admin authentication and dashboard
- Create event management pages (list, create, edit, archive)
- Implement gallery enhancements (search, sorting, bulk download)
- Add email configuration and archive management pages
- Integrate Umami analytics with tracking throughout the app
- Add comprehensive error boundaries and loading states
- Implement accessibility features (WCAG 2.1 AA compliance)
- Create theme system with preset themes and customization
- Add branding settings and company information management
- Fix backend database initialization and health check
- Configure proper API URLs and environment variables

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/index.css

@@ -6,13 +6,29 @@
 
 @layer base {
   :root {
-    --color-primary: 92 135 98;
+    /* Theme CSS Variables */
+    --color-primary: #5C8762;
+    --color-primary-light: #7aa583;
+    --color-primary-dark: #4a6f4f;
+    --color-accent: #22c55e;
+    --color-background: #fafafa;
+    --color-text: #171717;
+    --font-family: 'Inter', 'Noto Sans', system-ui, -apple-system, sans-serif;
+    --border-radius: 0.5rem;
+    
+    /* Tailwind RGB values for primary color */
+    --tw-color-primary: 92 135 98;
     --radius: 0.5rem;
   }
 
+  * {
+    font-family: var(--font-family);
+  }
 
   body {
-    @apply bg-neutral-50 text-neutral-900 antialiased;
+    background-color: var(--color-background);
+    color: var(--color-text);
+    @apply antialiased;
   }
 
   /* Custom scrollbar */
@@ -37,11 +53,18 @@
 @layer components {
   /* Button styles */
   .btn {
-    @apply inline-flex items-center justify-center rounded-lg font-medium transition-all duration-200 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-offset-2 disabled:pointer-events-none disabled:opacity-50;
+    @apply inline-flex items-center justify-center font-medium transition-all duration-200 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-offset-2 disabled:pointer-events-none disabled:opacity-50;
+    border-radius: var(--border-radius);
   }
 
   .btn-primary {
-    @apply bg-primary-600 text-white hover:bg-primary-700 focus-visible:ring-primary-600;
+    background-color: var(--color-primary);
+    color: white;
+    @apply hover:opacity-90 focus-visible:ring-2;
+  }
+  
+  .btn-primary:hover {
+    background-color: var(--color-primary-dark);
   }
 
   .btn-secondary {