style: strip to grayscale wireframe

- Remap all non-gray colors (blue, green, red, purple, slate) to gray
  equivalents via Tailwind v4 @theme overrides in layout.css
- Zero out all border-radius values (square everything)
- Zero out all shadow values (no depth)
- Disable all transitions and animations globally
- Change theme-color meta tag from purple (#7B2D8E) to gray (#6b7280)
- Clean up undefined 'underlined' class and typo bg-grey-200

src/routes/layout.css

@@ -1,3 +1,88 @@
 @import 'tailwindcss';
 @plugin '@tailwindcss/forms';
 @plugin '@tailwindcss/typography';
+
+/* ------------------------------------------------------------------ */
+/*  Wireframe theme — remap all non-gray colors to grayscale           */
+/* ------------------------------------------------------------------ */
+@theme {
+  /* blue → gray */
+  --color-blue-50: #f3f4f6;
+  --color-blue-100: #e5e7eb;
+  --color-blue-200: #d1d5db;
+  --color-blue-300: #9ca3af;
+  --color-blue-400: #6b7280;
+  --color-blue-500: #6b7280;
+  --color-blue-600: #4b5563;
+  --color-blue-700: #374151;
+  --color-blue-800: #1f2937;
+  /* green → gray */
+  --color-green-50: #f3f4f6;
+  --color-green-100: #e5e7eb;
+  --color-green-200: #d1d5db;
+  --color-green-300: #9ca3af;
+  --color-green-400: #6b7280;
+  --color-green-500: #6b7280;
+  --color-green-600: #4b5563;
+  --color-green-700: #374151;
+  --color-green-800: #1f2937;
+  /* red → gray */
+  --color-red-50: #f3f4f6;
+  --color-red-100: #e5e7eb;
+  --color-red-200: #d1d5db;
+  --color-red-300: #9ca3af;
+  --color-red-400: #6b7280;
+  --color-red-500: #6b7280;
+  --color-red-600: #4b5563;
+  --color-red-700: #374151;
+  --color-red-800: #1f2937;
+  /* purple → gray */
+  --color-purple-50: #f3f4f6;
+  --color-purple-100: #e5e7eb;
+  --color-purple-200: #d1d5db;
+  --color-purple-300: #9ca3af;
+  --color-purple-400: #6b7280;
+  --color-purple-500: #6b7280;
+  --color-purple-600: #4b5563;
+  --color-purple-700: #374151;
+  --color-purple-800: #1f2937;
+  --color-purple-900: #111827;
+  /* slate → gray */
+  --color-slate-50: #f8fafc;
+  --color-slate-100: #f1f5f9;
+  --color-slate-200: #e2e8f0;
+  --color-slate-300: #cbd5e1;
+  --color-slate-400: #94a3b8;
+  --color-slate-500: #64748b;
+  --color-slate-600: #475569;
+  --color-slate-700: #334155;
+  --color-slate-800: #1e293b;
+  --color-slate-900: #111827;
+
+  /* zero out decorative radii */
+  --radius: 0px;
+  --radius-sm: 0px;
+  --radius-md: 0px;
+  --radius-lg: 0px;
+  --radius-xl: 0px;
+  --radius-2xl: 0px;
+  --radius-3xl: 0px;
+
+  /* zero out shadows */
+  --shadow-sm: 0 0 #0000;
+  --shadow: 0 0 #0000;
+  --shadow-md: 0 0 #0000;
+  --shadow-lg: 0 0 #0000;
+  --shadow-xl: 0 0 #0000;
+  --shadow-2xl: 0 0 #0000;
+}
+
+/* ------------------------------------------------------------------ */
+/*  Force-disable transitions, animations, and remaining decoration    */
+/* ------------------------------------------------------------------ */
+*,
+::before,
+::after {
+  transition: none !important;
+  animation: none !important;
+}