style: overhaul design to authentic Google Gemini Material 3 Dark theme

frontend/tailwind.config.js

@@ -6,17 +6,21 @@ export default {
     extend: {
       colors: {
         gemini: {
-          bg: '#0b0f19',
-          surface: '#131314',
-          card: '#1e1f20',
-          hover: '#282a2c',
-          blue: '#8ab4f8',
-          purple: '#c58af9',
-          keep: '#81c995',
-          discard: '#f28b82',
+          canvas: '#131314',
+          surface: '#1e1f20',
+          elevated: '#282a2c',
+          hover: '#333537',
+          border: '#3c4043',
+          subtle: 'rgba(255, 255, 255, 0.08)',
+          blue: '#a8c7fa',
+          blueContainer: '#004a77',
+          blueOnContainer: '#d3e3fd',
+          green: '#a8dab5',
+          red: '#f28b82',
+          yellow: '#fdd663',
           text: '#e3e3e3',
-          muted: '#9aa0a6',
-          subtle: '#5f6368',
+          secondary: '#c4c7c5',
+          tertiary: '#8e918f',
         },
       },
       fontFamily: {
@@ -24,9 +28,8 @@ export default {
         mono: ['JetBrains Mono', 'Fira Code', 'monospace'],
       },
       boxShadow: {
-        'gemini-glow': '0 0 28px -4px rgba(138, 180, 248, 0.22)',
-        'purple-glow': '0 0 32px -4px rgba(197, 138, 249, 0.35)',
-        'card-depth': '0 20px 50px -12px rgba(0, 0, 0, 0.7)',
+        soft: '0 1px 3px 0 rgba(0, 0, 0, 0.3), 0 1px 2px -1px rgba(0, 0, 0, 0.2)',
+        card: '0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.2)',
       },
     },
   },