refactor: 调整滚动条样式，删除OverlayScrollbar组件及其样式

web/src/app/globals.css

@@ -134,15 +134,15 @@ html, body {
 }
 
 ::-webkit-scrollbar {
-  width: 4px;           /* 垂直滚动条宽度 */
+  width: 2px;           /* 垂直滚动条宽度 */
-  height: 4px;          /* 水平滚动条高度 */
+  height: 2px;          /* 水平滚动条高度 */
   background: transparent; /* 滚动条轨道背景 */
   position: absolute;   /* 实际不会影响内容布局 */
 }
 
 ::-webkit-scrollbar-thumb {
   background: rgba(0,0,0,0.15); /* 滚动条滑块颜色 */
-  border-radius: 4px;
+  border-radius: 2px;
 }
 
 ::-webkit-scrollbar-thumb:hover {

web/src/components/layout/navbar-or-side.tsx

@@ -19,6 +19,7 @@ import { Sheet, SheetContent, SheetTitle, SheetTrigger } from "@/components/ui/s
 import { Menu } from "lucide-react"
 import { ThemeModeToggle } from "../common/theme-toggle"
 import { AvatarWithDropdownMenu } from "./avatar-with-dropdown-menu"
+import { cn } from "@/lib/utils"
 
 const navbarMenuComponents = [
   {
@@ -70,14 +71,14 @@ function NavMenuCenter() {
         {navbarMenuComponents.map((item) => (
           <NavigationMenuItem key={item.title}>
             {item.href ? (
-              <NavigationMenuLink asChild className={navigationMenuTriggerStyle()}>
+              <NavigationMenuLink asChild className={cn(navigationMenuTriggerStyle(), "bg-transparent")}>
                 <Link href={item.href} className="flex items-center gap-1 font-extrabold">
                   <span>{item.title}</span>
                 </Link>
               </NavigationMenuLink>
             ) : item.children ? (
               <>
-                <NavigationMenuTrigger className="flex items-center gap-1 font-extrabold">
+                <NavigationMenuTrigger className="flex items-center gap-1 font-extrabold bg-transparent">
                   <span>{item.title}</span>
                 </NavigationMenuTrigger>
                 <NavigationMenuContent>

web/src/components/overlay/OverlayScrollbar.tsx

@@ -1,104 +0,0 @@
-import React, { useEffect, useRef, useState } from "react";
-import styles from "./overlay-scrollbar.module.css";
-
-export default function OverlayScrollbar({
-  children,
-  className,
-  style,
-}: {
-  children: React.ReactNode;
-  className?: string;
-  style?: React.CSSProperties;
-}) {
-  const scrollRef = useRef<HTMLDivElement | null>(null);
-  const thumbRef = useRef<HTMLDivElement | null>(null);
-  const [thumbHeight, setThumbHeight] = useState(0);
-  const [thumbTop, setThumbTop] = useState(0);
-  const dragging = useRef(false);
-  const startY = useRef(0);
-  const startScrollTop = useRef(0);
-
-  useEffect(() => {
-    const el = scrollRef.current;
-    if (!el) return;
-
-    const update = () => {
-      const visible = el.clientHeight;
-      const total = el.scrollHeight;
-      const ratio = visible / Math.max(total, 1);
-      const h = Math.max(ratio * visible, 24);
-      const top = total > visible ? (el.scrollTop / (total - visible)) * (visible - h) : 0;
-      setThumbHeight(h);
-      setThumbTop(isFinite(top) ? top : 0);
-
-      if (thumbRef.current) {
-        const percent = total > visible ? Math.round((el.scrollTop / (total - visible)) * 100) : 0;
-        thumbRef.current.setAttribute("aria-valuenow", String(percent));
-      }
-    };
-
-    update();
-    el.addEventListener("scroll", update, { passive: true });
-    window.addEventListener("resize", update);
-    const obs = new MutationObserver(update);
-    obs.observe(el, { childList: true, subtree: true });
-
-    return () => {
-      el.removeEventListener("scroll", update);
-      window.removeEventListener("resize", update);
-      obs.disconnect();
-    };
-  }, []);
-
-  useEffect(() => {
-    const onMove = (e: MouseEvent) => {
-      if (!dragging.current || !scrollRef.current) return;
-      const el = scrollRef.current;
-      const visible = el.clientHeight;
-      const total = el.scrollHeight;
-      const h = thumbHeight;
-      const delta = e.clientY - startY.current;
-      const proportion = delta / Math.max(visible - h, 1);
-      el.scrollTop = Math.min(Math.max(startScrollTop.current + proportion * (total - visible), 0), total - visible);
-    };
-    const onUp = () => {
-      dragging.current = false;
-      document.body.style.userSelect = "";
-    };
-
-    window.addEventListener("mousemove", onMove);
-    window.addEventListener("mouseup", onUp);
-    return () => {
-      window.removeEventListener("mousemove", onMove);
-      window.removeEventListener("mouseup", onUp);
-    };
-  }, [thumbHeight]);
-
-  const onThumbMouseDown = (e: React.MouseEvent) => {
-    dragging.current = true;
-    startY.current = e.clientY;
-    if (scrollRef.current) startScrollTop.current = scrollRef.current.scrollTop;
-    document.body.style.userSelect = "none";
-  };
-
-  return (
-    <div className={`${styles.container} ${className || ""}`} style={{ position: "relative", ...style }}>
-      <div ref={scrollRef} className={styles.content} tabIndex={0}>
-        {children}
-      </div>
-
-      <div className={styles.track} aria-hidden={false}>
-        <div
-          ref={thumbRef}
-          role="scrollbar"
-          aria-orientation="vertical"
-          aria-valuemin={0}
-          aria-valuemax={100}
-          className={styles.thumb}
-          style={{ height: thumbHeight, transform: `translateY(${thumbTop}px)` }}
-          onMouseDown={onThumbMouseDown}
-        />
-      </div>
-    </div>
-  );
-}

web/src/components/overlay/overlay-scrollbar.module.css

@@ -1,35 +0,0 @@
-.container {
-  position: relative;
-}
-.content {
-  overflow: auto;
-  max-height: 100%;
-  /* hide native scrollbars but keep scrolling */
-  -ms-overflow-style: none; /* IE and Edge */
-  scrollbar-width: none; /* Firefox */
-}
-.content::-webkit-scrollbar {
-  display: none; /* Chrome/Safari */
-}
-.track {
-  pointer-events: none; /* track itself not interactive */
-  position: absolute;
-  right: 8px;
-  top: 0;
-  bottom: 0;
-  width: 12px;
-  display: flex;
-  align-items: flex-start;
-  justify-content: center;
-}
-.thumb {
-  pointer-events: auto; /* thumb is interactive */
-  width: 8px;
-  margin-top: 4px;
-  background: rgba(0, 0, 0, 0.32);
-  border-radius: 9999px;
-  transition: background 0.12s ease;
-}
-.thumb:hover {
-  background: rgba(0, 0, 0, 0.6);
-}