feat: integrate Tailwind CSS with custom theme and animations

Added Tailwind CSS and tw-animate-css imports to globals.css. Introduced a custom dark variant and an extensive @theme inline block with CSS variables for colors, radii, and animations. Included keyframes for shimmer-slide, spin-around, gradient, shine, and background-position-spin to enable consistent theming and dynamic UI effects across the application.

lib/utils.ts

@@ -0,0 +1,6 @@
+import { clsx, type ClassValue } from "clsx"
+import { twMerge } from "tailwind-merge"
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs))
+}