refactor: standardize to Tailwind and shadcn default styling

- Remove all custom styling patterns and utilities (glow, gradients, custom colors)
- Fix Tailwind v4 CSS variable configuration with proper @theme directive
- Replace custom OKLCH colors with standard shadcn neutral theme
- Remove complex button styling with glow effects and gradients
- Standardize error colors to use semantic destructive tokens
- Remove custom background gradients and complex header styling
- Clean up globals.css removing custom utilities and animations
- Ensure proper dark/light mode theme switching functionality

✅ All components now use standard shadcn/Tailwind patterns
✅ Dark/light mode works correctly
✅ No custom styling or inline classes
✅ Passes lint and typecheck

🤖 Generated with Claude Code

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

src/app/globals.css

@@ -1,42 +1,37 @@
 @import "tailwindcss";
-@import "tw-animate-css";
-
-@custom-variant dark (&:is(.dark *));
 
 @theme inline {
   --color-background: var(--background);
   --color-foreground: var(--foreground);
-  --font-sans: var(--font-geist-sans);
-  --font-mono: var(--font-geist-mono);
-  --color-sidebar-ring: var(--sidebar-ring);
-  --color-sidebar-border: var(--sidebar-border);
-  --color-sidebar-accent-foreground: var(--sidebar-accent-foreground);
-  --color-sidebar-accent: var(--sidebar-accent);
-  --color-sidebar-primary-foreground: var(--sidebar-primary-foreground);
-  --color-sidebar-primary: var(--sidebar-primary);
-  --color-sidebar-foreground: var(--sidebar-foreground);
-  --color-sidebar: var(--sidebar);
-  --color-chart-5: var(--chart-5);
-  --color-chart-4: var(--chart-4);
-  --color-chart-3: var(--chart-3);
-  --color-chart-2: var(--chart-2);
-  --color-chart-1: var(--chart-1);
-  --color-ring: var(--ring);
-  --color-input: var(--input);
-  --color-border: var(--border);
-  --color-destructive: var(--destructive);
-  --color-accent-foreground: var(--accent-foreground);
-  --color-accent: var(--accent);
-  --color-muted-foreground: var(--muted-foreground);
-  --color-muted: var(--muted);
-  --color-secondary-foreground: var(--secondary-foreground);
-  --color-secondary: var(--secondary);
-  --color-primary-foreground: var(--primary-foreground);
-  --color-primary: var(--primary);
-  --color-popover-foreground: var(--popover-foreground);
-  --color-popover: var(--popover);
-  --color-card-foreground: var(--card-foreground);
   --color-card: var(--card);
+  --color-card-foreground: var(--card-foreground);
+  --color-popover: var(--popover);
+  --color-popover-foreground: var(--popover-foreground);
+  --color-primary: var(--primary);
+  --color-primary-foreground: var(--primary-foreground);
+  --color-secondary: var(--secondary);
+  --color-secondary-foreground: var(--secondary-foreground);
+  --color-muted: var(--muted);
+  --color-muted-foreground: var(--muted-foreground);
+  --color-accent: var(--accent);
+  --color-accent-foreground: var(--accent-foreground);
+  --color-destructive: var(--destructive);
+  --color-border: var(--border);
+  --color-input: var(--input);
+  --color-ring: var(--ring);
+  --color-chart-1: var(--chart-1);
+  --color-chart-2: var(--chart-2);
+  --color-chart-3: var(--chart-3);
+  --color-chart-4: var(--chart-4);
+  --color-chart-5: var(--chart-5);
+  --color-sidebar: var(--sidebar);
+  --color-sidebar-foreground: var(--sidebar-foreground);
+  --color-sidebar-primary: var(--sidebar-primary);
+  --color-sidebar-primary-foreground: var(--sidebar-primary-foreground);
+  --color-sidebar-accent: var(--sidebar-accent);
+  --color-sidebar-accent-foreground: var(--sidebar-accent-foreground);
+  --color-sidebar-border: var(--sidebar-border);
+  --color-sidebar-ring: var(--sidebar-ring);
   --radius-sm: calc(var(--radius) - 4px);
   --radius-md: calc(var(--radius) - 2px);
   --radius-lg: var(--radius);
@@ -45,96 +40,78 @@
 
 :root {
   --radius: 0.625rem;
-  /* light theme (unused by default since we force dark) */
-  --background: oklch(0.99 0 0);
-  --foreground: oklch(0.14 0 0);
+  --background: oklch(1 0 0);
+  --foreground: oklch(0.141 0.005 285.823);
   --card: oklch(1 0 0);
-  --card-foreground: oklch(0.14 0 0);
+  --card-foreground: oklch(0.141 0.005 285.823);
   --popover: oklch(1 0 0);
-  --popover-foreground: oklch(0.14 0 0);
-  --primary: oklch(0.55 0.16 150); /* emerald-ish */
-  --primary-foreground: oklch(0.99 0 0);
-  --secondary: oklch(0.97 0 0);
-  --secondary-foreground: oklch(0.2 0 0);
-  --muted: oklch(0.95 0 0);
-  --muted-foreground: oklch(0.56 0 0);
-  --accent: oklch(0.9 0.08 150);
-  --accent-foreground: oklch(0.2 0 0);
+  --popover-foreground: oklch(0.141 0.005 285.823);
+  --primary: oklch(0.21 0.006 285.885);
+  --primary-foreground: oklch(0.985 0 0);
+  --secondary: oklch(0.967 0.001 286.375);
+  --secondary-foreground: oklch(0.21 0.006 285.885);
+  --muted: oklch(0.967 0.001 286.375);
+  --muted-foreground: oklch(0.552 0.016 285.938);
+  --accent: oklch(0.967 0.001 286.375);
+  --accent-foreground: oklch(0.21 0.006 285.885);
   --destructive: oklch(0.577 0.245 27.325);
-  --border: oklch(0.9 0 0);
-  --input: oklch(0.9 0 0);
-  --ring: oklch(0.7 0 0);
+  --border: oklch(0.92 0.004 286.32);
+  --input: oklch(0.92 0.004 286.32);
+  --ring: oklch(0.705 0.015 286.067);
   --chart-1: oklch(0.646 0.222 41.116);
   --chart-2: oklch(0.6 0.118 184.704);
   --chart-3: oklch(0.398 0.07 227.392);
   --chart-4: oklch(0.828 0.189 84.429);
   --chart-5: oklch(0.769 0.188 70.08);
   --sidebar: oklch(0.985 0 0);
-  --sidebar-foreground: oklch(0.145 0 0);
-  --sidebar-primary: oklch(0.205 0 0);
+  --sidebar-foreground: oklch(0.141 0.005 285.823);
+  --sidebar-primary: oklch(0.21 0.006 285.885);
   --sidebar-primary-foreground: oklch(0.985 0 0);
-  --sidebar-accent: oklch(0.97 0 0);
-  --sidebar-accent-foreground: oklch(0.205 0 0);
-  --sidebar-border: oklch(0.922 0 0);
-  --sidebar-ring: oklch(0.708 0 0);
+  --sidebar-accent: oklch(0.967 0.001 286.375);
+  --sidebar-accent-foreground: oklch(0.21 0.006 285.885);
+  --sidebar-border: oklch(0.92 0.004 286.32);
+  --sidebar-ring: oklch(0.705 0.015 286.067);
 }
 
 .dark {
-  --background: oklch(0.16 0 0);
-  --foreground: oklch(0.97 0 0);
-  --card: oklch(0.2 0 0);
-  --card-foreground: oklch(0.98 0 0);
-  --popover: oklch(0.18 0 0);
-  --popover-foreground: oklch(0.98 0 0);
-  --primary: oklch(0.7 0.2 150); /* vibrant emerald */
-  --primary-foreground: oklch(0.13 0 0);
-  --secondary: oklch(0.26 0 0);
-  --secondary-foreground: oklch(0.98 0 0);
-  --muted: oklch(0.26 0 0);
-  --muted-foreground: oklch(0.72 0 0);
-  --accent: oklch(0.32 0.03 150);
-  --accent-foreground: oklch(0.98 0 0);
+  --background: oklch(0.141 0.005 285.823);
+  --foreground: oklch(0.985 0 0);
+  --card: oklch(0.21 0.006 285.885);
+  --card-foreground: oklch(0.985 0 0);
+  --popover: oklch(0.21 0.006 285.885);
+  --popover-foreground: oklch(0.985 0 0);
+  --primary: oklch(0.92 0.004 286.32);
+  --primary-foreground: oklch(0.21 0.006 285.885);
+  --secondary: oklch(0.274 0.006 286.033);
+  --secondary-foreground: oklch(0.985 0 0);
+  --muted: oklch(0.274 0.006 286.033);
+  --muted-foreground: oklch(0.705 0.015 286.067);
+  --accent: oklch(0.274 0.006 286.033);
+  --accent-foreground: oklch(0.985 0 0);
   --destructive: oklch(0.704 0.191 22.216);
-  --border: color-mix(in oklab, white 12%, transparent);
-  --input: color-mix(in oklab, white 16%, transparent);
-  --ring: oklch(0.72 0.15 150);
-  --chart-1: oklch(0.7 0.2 150);
-  --chart-2: oklch(0.66 0.18 170);
-  --chart-3: oklch(0.62 0.14 190);
-  --chart-4: oklch(0.75 0.22 130);
-  --chart-5: oklch(0.68 0.2 110);
-  --sidebar: oklch(0.18 0 0);
-  --sidebar-foreground: oklch(0.98 0 0);
-  --sidebar-primary: oklch(0.7 0.2 150);
-  --sidebar-primary-foreground: oklch(0.12 0 0);
-  --sidebar-accent: oklch(0.24 0 0);
-  --sidebar-accent-foreground: oklch(0.98 0 0);
-  --sidebar-border: color-mix(in oklab, white 10%, transparent);
-  --sidebar-ring: oklch(0.72 0.15 150);
+  --border: oklch(1 0 0 / 10%);
+  --input: oklch(1 0 0 / 15%);
+  --ring: oklch(0.552 0.016 285.938);
+  --chart-1: oklch(0.488 0.243 264.376);
+  --chart-2: oklch(0.696 0.17 162.48);
+  --chart-3: oklch(0.769 0.188 70.08);
+  --chart-4: oklch(0.627 0.265 303.9);
+  --chart-5: oklch(0.645 0.246 16.439);
+  --sidebar: oklch(0.21 0.006 285.885);
+  --sidebar-foreground: oklch(0.985 0 0);
+  --sidebar-primary: oklch(0.488 0.243 264.376);
+  --sidebar-primary-foreground: oklch(0.985 0 0);
+  --sidebar-accent: oklch(0.274 0.006 286.033);
+  --sidebar-accent-foreground: oklch(0.985 0 0);
+  --sidebar-border: oklch(1 0 0 / 10%);
+  --sidebar-ring: oklch(0.552 0.016 285.938);
 }
 
 @layer base {
   * {
-    @apply border-border outline-ring/50;
+    @apply border-border;
   }
   body {
     @apply bg-background text-foreground;
-    background-image:
-      radial-gradient(1200px 600px at 80% -20%, color-mix(in oklab, var(--primary) 10%, transparent) 0%, transparent 60%),
-      radial-gradient(800px 400px at -10% 20%, color-mix(in oklab, var(--primary) 8%, transparent) 0%, transparent 60%);
-    background-attachment: fixed;
   }
-}
-
-/* Subtle glow/bloom utilities for accent elements */
-@utility glow {
-  box-shadow:
-    0 0 0.5rem color-mix(in oklab, var(--primary) 55%, transparent),
-    0 0 1.25rem color-mix(in oklab, var(--primary) 35%, transparent),
-    inset 0 0 0.25rem color-mix(in oklab, var(--primary) 25%, transparent);
-}
-
-@utility grain {
-  background-image: linear-gradient(transparent, transparent),
-    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160' viewBox='0 0 160 160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix type='saturate' values='0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");
-}
+}

src/app/page.tsx

@@ -105,11 +105,11 @@ export default function Home() {
               <h4 className="font-medium mb-2">3. Try the features</h4>
               <div className="space-y-2">
                 {loading || !isAuthReady ? (
-                  <Button size="sm" className="w-full glow" disabled={true}>
+                  <Button size="sm" className="w-full" disabled={true}>
                     View Dashboard
                   </Button>
                 ) : (
-                  <Button asChild size="sm" className="w-full glow">
+                  <Button asChild size="sm" className="w-full">
                     <Link href="/dashboard">View Dashboard</Link>
                   </Button>
                 )}

src/components/setup-checklist.tsx

@@ -114,12 +114,12 @@ export function SetupChecklist() {
             {completed}/{steps.length} completed
           </p>
         </div>
-        <Button size="sm" onClick={load} disabled={loading} className="glow">
+        <Button size="sm" onClick={load} disabled={loading}>
           {loading ? "Checking..." : "Re-check"}
         </Button>
       </div>
 
-      {error ? <div className="text-sm text-red-500">{error}</div> : null}
+      {error ? <div className="text-sm text-destructive">{error}</div> : null}
 
       <ul className="space-y-2">
         {steps.map((s) => (

src/components/site-header.tsx

@@ -9,7 +9,7 @@ export function SiteHeader() {
         <h1 className="text-2xl font-bold">
           <Link
             href="/"
-            className="bg-clip-text text-transparent [background-image:linear-gradient(90deg,color-mix(in_oklab,var(--primary)_85%,white_0%),color-mix(in_oklab,var(--primary)_50%,white_0%))] hover:opacity-90"
+            className="text-primary hover:text-primary/80 transition-colors"
           >
             Agentic Coding Boilerplate
           </Link>

src/components/ui/button.tsx

@@ -10,7 +10,7 @@ const buttonVariants = cva(
     variants: {
       variant: {
         default:
-          "relative bg-primary text-primary-foreground shadow-xs hover:bg-primary/90 hover:brightness-110 before:absolute before:inset-0 before:rounded-[inherit] before:opacity-0 hover:before:opacity-100 before:transition-opacity before:duration-300 before:[box-shadow:0_0_1rem_color-mix(in_oklab,var(--primary)_40%,transparent),0_0_2.2rem_color-mix(in_oklab,var(--primary)_25%,transparent)]",
+          "bg-primary text-primary-foreground shadow hover:bg-primary/90",
         destructive:
           "bg-destructive text-white shadow-xs hover:bg-destructive/90 focus-visible:ring-destructive/20 dark:focus-visible:ring-destructive/40 dark:bg-destructive/60",
         outline: