Fix fumadocs component styles by adding Tailwind v4 compatible CSS

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

apps/site/app/global.css

@@ -2,4 +2,80 @@
 @import 'fumadocs-ui/css/neutral.css';
 @import 'fumadocs-ui/css/preset.css';
 
+/* Scan sources for Tailwind classes */
 @source '../node_modules/fumadocs-ui/dist/**/*.js';
+@source '../../packages/components/src/**/*.{ts,tsx}';
+@source '../../packages/react/src/**/*.{ts,tsx}';
+@source '../../packages/plugin-*/src/**/*.{ts,tsx}';
+
+/* ObjectUI component CSS custom properties */
+:root {
+  --background: 0 0% 100%;
+  --foreground: 222.2 84% 4.9%;
+
+  --card: 0 0% 100%;
+  --card-foreground: 222.2 84% 4.9%;
+
+  --popover: 0 0% 100%;
+  --popover-foreground: 222.2 84% 4.9%;
+
+  --primary: 222.2 47.4% 11.2%;
+  --primary-foreground: 210 40% 98%;
+
+  --secondary: 210 40% 96.1%;
+  --secondary-foreground: 222.2 47.4% 11.2%;
+
+  --muted: 210 40% 96.1%;
+  --muted-foreground: 215.4 16.3% 46.9%;
+
+  --accent: 210 40% 96.1%;
+  --accent-foreground: 222.2 47.4% 11.2%;
+
+  --destructive: 0 84.2% 60.2%;
+  --destructive-foreground: 210 40% 98%;
+
+  --border: 214.3 31.8% 91.4%;
+  --input: 214.3 31.8% 91.4%;
+  --ring: 222.2 84% 4.9%;
+
+  --radius: 0.5rem;
+}
+
+.dark {
+  --background: 222.2 84% 4.9%;
+  --foreground: 210 40% 98%;
+
+  --card: 222.2 84% 4.9%;
+  --card-foreground: 210 40% 98%;
+
+  --popover: 222.2 84% 4.9%;
+  --popover-foreground: 210 40% 98%;
+
+  --primary: 210 40% 98%;
+  --primary-foreground: 222.2 47.4% 11.2%;
+
+  --secondary: 217.2 32.6% 17.5%;
+  --secondary-foreground: 210 40% 98%;
+
+  --muted: 217.2 32.6% 17.5%;
+  --muted-foreground: 215 20.2% 65.1%;
+
+  --accent: 217.2 32.6% 17.5%;
+  --accent-foreground: 210 40% 98%;
+
+  --destructive: 0 62.8% 30.6%;
+  --destructive-foreground: 210 40% 98%;
+
+  --border: 217.2 32.6% 17.5%;
+  --input: 217.2 32.6% 17.5%;
+  --ring: 212.7 26.8% 83.9%;
+}
+
+* {
+  border-color: hsl(var(--border));
+}
+
+body {
+  background-color: hsl(var(--background));
+  color: hsl(var(--foreground));
+}