fix: remove page reload from theme changes, rely on dark class application

src/app/layout.tsx

@@ -23,6 +23,25 @@ export const metadata: Metadata = {
   },
 };
 
+// Add global CSS variable definitions
+const themeStylesheet = `
+  :root {
+    --bg-primary: #f8fafc;
+    --bg-secondary: #f1f5f9;
+    --text-primary: #1e293b;
+    --text-secondary: #64748b;
+    --border-color: #e2e8f0;
+  }
+  
+  html.dark {
+    --bg-primary: #0f172a;
+    --bg-secondary: #1e293b;
+    --text-primary: #f1f5f9;
+    --text-secondary: #cbd5e1;
+    --border-color: #334155;
+  }
+`;
+
 export default function RootLayout({
   children,
 }: Readonly<{