Replace index.css with CODE-NARRATIVE-AI styling (glass-nav, scrollbar, animations)

frontend/src/index.css

@@ -2,67 +2,34 @@
 @tailwind components;
 @tailwind utilities;
 
-* {
-  margin: 0;
-  padding: 0;
-  box-sizing: border-box;
-}
-
-html {
-  scroll-behavior: smooth;
-}
+* { margin: 0; padding: 0; box-sizing: border-box; }
+html { scroll-behavior: smooth; }
 
 body {
-  background: #0a0a0f;
-  color: #ffffff;
-  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Inter', Roboto, sans-serif;
+  font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, sans-serif;
   -webkit-font-smoothing: antialiased;
   -moz-osx-font-smoothing: grayscale;
 }
 
-::selection {
-  background: rgba(16, 185, 129, 0.2);
-  color: #ffffff;
-}
-
-::-webkit-scrollbar {
-  width: 6px;
-  height: 6px;
-}
+::selection { background: rgba(16, 185, 129, 0.15); }
 
-::-webkit-scrollbar-track {
-  background: transparent;
-}
+::-webkit-scrollbar { width: 6px; height: 6px; }
+::-webkit-scrollbar-track { background: transparent; }
+::-webkit-scrollbar-thumb { background: #334155; border-radius: 3px; }
+::-webkit-scrollbar-thumb:hover { background: #475569; }
 
-::-webkit-scrollbar-thumb {
-  background: #2a2a3e;
-  border-radius: 3px;
-}
+pre { tab-size: 2; }
 
-::-webkit-scrollbar-thumb:hover {
-  background: #3a3a5e;
-}
-
-/* Code blocks */
-pre {
-  tab-size: 2;
-}
-
-/* Animations */
 @keyframes fadeIn {
   from { opacity: 0; transform: translateY(8px); }
   to { opacity: 1; transform: translateY(0); }
 }
-
-.animate-fade-in {
-  animation: fadeIn 0.3s ease-out;
-}
+.animate-fade-in { animation: fadeIn 0.4s ease-out; }
 
 @keyframes shimmer {
   0% { background-position: -200% 0; }
   100% { background-position: 200% 0; }
 }
-
 .animate-shimmer {
   background: linear-gradient(90deg, transparent, rgba(255,255,255,0.03), transparent);
   background-size: 200% 100%;