polish(frontend): 修正中文字重发虚，并疏朗首页与数据区

补齐 Noto 600/800 并关闭伪粗；Header 加大加粗导航并加板块入口；去掉灰块底、加大列表行距，站点数据格居中缩小数字。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/components/CommentSection.tsx

@@ -486,8 +486,8 @@ export default function CommentSection({
         </form>
       ) : (
         <div
-          className="mb-8 px-5 py-4 rounded-2xl flex items-center justify-between gap-4 flex-wrap"
-          style={{ background: "var(--panel-2)" }}
+          className="mb-8 px-5 py-4 rounded-2xl flex items-center justify-between gap-4 flex-wrap border"
+          style={{ borderColor: "var(--line)", background: "transparent" }}
         >
           <span className="text-sm" style={{ color: "var(--ink-2)" }}>
             登录后参与讨论

frontend/components/Header.tsx

@@ -20,6 +20,7 @@ import {
   ChevronDown,
   ShieldCheck,
   MessageSquare,
+  LayoutGrid,
 } from "lucide-react";
 import { apiLogout, apiMe, apiChatUnreadSummary, type User } from "@/lib/api";
 import { hasAuthCookieHint } from "@/lib/cookies";
@@ -233,14 +234,21 @@ export default function Header({
               </span>
             </span>
           </Link>
-          <nav className="hidden lg:flex items-center gap-1 pl-3" style={{ borderLeft: "1px solid var(--line)" }}>
-            <NavPill href="/" active={pathname === "/"} icon={<Home size={14} />}>
+          <nav className="hidden lg:flex items-center gap-1.5 pl-3" style={{ borderLeft: "1px solid var(--line)" }}>
+            <NavPill href="/" active={pathname === "/"} icon={<Home size={15} />}>
               首页
             </NavPill>
+            <NavPill
+              href="/boards"
+              active={pathname === "/boards" || pathname?.startsWith("/board/") === true}
+              icon={<LayoutGrid size={15} />}
+            >
+              板块
+            </NavPill>
           </nav>
         </div>
 
-        {/* 中部留白：为后续主导航菜单项预留位置 */}
+        {/* 中部弹性留白，把搜索与操作区推到右侧 */}
         <div className="hidden lg:block flex-1" aria-hidden />
 
         {/* 右侧操作区：搜索靠右停靠 + 桌面/移动共用铃铛（仅挂载一次，避免重复轮询），
@@ -370,6 +378,12 @@ export default function Header({
           </form>
           <div className="flex flex-col">
             <MobileLink href="/" active={pathname === "/"}>首页</MobileLink>
+            <MobileLink
+              href="/boards"
+              active={pathname === "/boards" || pathname?.startsWith("/board/") === true}
+            >
+              板块
+            </MobileLink>
             {user && <MobileLink href="/compose">发帖</MobileLink>}
             {user && (
               <MobileLink href="/chat" active={pathname?.startsWith("/chat") ?? false}>
@@ -431,11 +445,11 @@ function NavPill({
   return (
     <Link
       href={href}
-      className="inline-flex items-center gap-1.5 px-3.5 py-2 rounded-full text-[13.5px] transition-colors"
+      className="inline-flex items-center gap-1.5 px-3.5 py-2 rounded-full text-[15px] font-semibold transition-colors"
       style={
         active
           ? { background: "var(--accent-soft)", color: "var(--accent)" }
-          : { color: "var(--ink-2)" }
+          : { color: "var(--ink)" }
       }
     >
       {icon}
@@ -456,7 +470,7 @@ function MobileLink({
   return (
     <Link
       href={href}
-      className="px-3 py-3 rounded-2xl text-[15px] transition-colors"
+      className="px-3 py-3 rounded-2xl text-[16px] font-semibold transition-colors"
       style={{
         color: active ? "var(--accent)" : "var(--ink)",
         background: active ? "var(--accent-soft)" : "transparent",

frontend/components/PostInteractPanels.tsx

@@ -72,10 +72,10 @@ function QuestionPanel({ postId, state }: { postId: number; state: QuestionState
   };
 
   return (
-    <section className="j13-interact-card">
+    <section className={`j13-interact-card${state.solved ? " is-solved" : " is-unsolved"}`}>
       <div className="flex flex-wrap items-center justify-between gap-3">
         <div>
-          <h2 className="font-semibold text-[15px]" style={{ color: "var(--ink)" }}>
+          <h2 className="text-[15px] font-medium" style={{ color: "var(--ink)" }}>
             问答 · {state.solved ? "已解决" : "未解决"}
           </h2>
           <p className="meta text-[12.5px] mt-1">

frontend/components/PostRow.tsx

@@ -40,8 +40,8 @@ export default function PostRow({
       }`}
       style={{
         borderColor: "var(--line)",
-        paddingTop: compact ? 11 : 18,
-        paddingBottom: compact ? 11 : 18,
+        paddingTop: compact ? 15 : 22,
+        paddingBottom: compact ? 15 : 22,
         animationDelay: `${Math.min(index, 9) * 35}ms`,
       }}
     >

frontend/components/home/CommunityPanels.tsx

@@ -154,7 +154,7 @@ function HotRanking({ posts }: { posts: PostListItem[] }) {
                 <span className="j13-rank-no">{i + 1}</span>
                 <span className="min-w-0 flex-1">
                   <span
-                    className="block truncate text-[13px] font-normal leading-snug transition-colors group-hover:text-[var(--accent)]"
+                    className="block truncate text-[13px] font-medium leading-snug transition-colors group-hover:text-[var(--accent)]"
                     style={{ color: "var(--ink)" }}
                   >
                     {p.title}
@@ -235,7 +235,7 @@ function ActiveUsers({ users }: { users: ActiveUser[] }) {
                   <Avatar name={name} src={u.avatar} size={30} />
                   <span className="flex-1 min-w-0">
                     <span
-                      className="block truncate text-[13px] leading-tight"
+                      className="block truncate text-[13px] font-medium leading-tight"
                       style={{ color: "var(--ink)" }}
                     >
                       {name}