feat: enhance user interface with improved styling and responsiveness

- Updated UserAvatar component to accept additional className for better customization.
- Refined ProfilePage layout with responsive avatar styling.
- Enhanced Header component with improved background and text styles.
- Improved PopularTags and TopFriends components with better spacing and text shadows.
- Updated ThoughtCard and ThoughtThread components for better visual hierarchy and responsiveness.
- Enhanced UI components (Button, Badge, Card, DropdownMenu, Input, Popover, Separator, Skeleton, Textarea) with new styles and effects.
- Added a new background image for visual enhancement.

thoughts-frontend/components/ui/separator.tsx

@@ -1,9 +1,9 @@
-"use client"
+"use client";
 
-import * as React from "react"
-import * as SeparatorPrimitive from "@radix-ui/react-separator"
+import * as React from "react";
+import * as SeparatorPrimitive from "@radix-ui/react-separator";
 
-import { cn } from "@/lib/utils"
+import { cn } from "@/lib/utils";
 
 function Separator({
   className,
@@ -17,12 +17,12 @@ function Separator({
       decorative={decorative}
       orientation={orientation}
       className={cn(
-        "bg-border shrink-0 data-[orientation=horizontal]:h-px data-[orientation=horizontal]:w-full data-[orientation=vertical]:h-full data-[orientation=vertical]:w-px",
+        "bg-border/50 shrink-0 data-[orientation=horizontal]:h-px data-[orientation=horizontal]:w-full data-[orientation=vertical]:h-full data-[orientation=vertical]:w-px",
         className
       )}
       {...props}
     />
-  )
+  );
 }
 
-export { Separator }
+export { Separator };