Fix mobile responsiveness and implement enhanced theme system

- Fixed mobile gallery login box sizing and layout
- Fixed header button layout for mobile screens
- Fixed duplicate logo issue on logout
- Fixed '0' rendering when upload button is hidden
- Fixed horizontal scrolling on small screens

- Implemented comprehensive theme system with gallery layouts
- Added 6 different gallery layouts: Grid, Masonry, Carousel, Timeline, Hero, Mosaic
- Created enhanced theme customizer with layout selection
- Added theme presets for different event types
- Updated event creation with theme preview and customization
- Fixed all TypeScript compilation errors

- Added missing translation keys for create event page
- Added translations for theme customization features

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

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

frontend/src/index.css

@@ -14,7 +14,10 @@
     --color-background: #fafafa;
     --color-text: #171717;
     --font-family: 'Inter', 'Noto Sans', system-ui, -apple-system, sans-serif;
+    --heading-font-family: 'Inter', 'Noto Sans', system-ui, -apple-system, sans-serif;
     --border-radius: 0.5rem;
+    --font-size-base: 16px;
+    --shadow-default: 0 4px 6px rgba(0,0,0,0.1);
     
     /* Tailwind RGB values for primary color */
     --tw-color-primary: 92 135 98;
@@ -28,7 +31,23 @@
   body {
     background-color: var(--color-background);
     color: var(--color-text);
+    font-size: var(--font-size-base);
     @apply antialiased;
+    overflow-x: hidden;
+  }
+  
+  body::before {
+    content: '';
+    position: fixed;
+    top: 0;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    background-image: var(--background-pattern);
+    background-size: var(--background-pattern-size);
+    opacity: 1;
+    pointer-events: none;
+    z-index: -1;
   }
 
   /* Custom scrollbar */
@@ -94,16 +113,22 @@
 
   /* Card styles */
   .card {
-    @apply rounded-xl border border-neutral-200 bg-white shadow-soft;
+    @apply rounded-xl border border-neutral-200 bg-white;
+    box-shadow: var(--shadow-default);
   }
 
   .card-hover {
-    @apply card transition-all duration-200 hover:shadow-medium hover:translate-y-[-2px];
+    @apply card transition-all duration-200 hover:translate-y-[-2px];
+  }
+  
+  /* Headings with custom font */
+  h1, h2, h3, h4, h5, h6 {
+    font-family: var(--heading-font-family);
   }
 
   /* Container */
   .container {
-    @apply mx-auto px-4 sm:px-6 lg:px-8 max-w-7xl;
+    @apply mx-auto px-4 sm:px-6 lg:px-8 max-w-7xl w-full;
   }
 
   /* Image loading skeleton */