refactor(frontend): PDF reader chrome to shadcn (B4)

frontend/src/readers/PdfReader.tsx

@@ -4,7 +4,8 @@ import * as pdfjs from "pdfjs-dist";
 import { apiRaw } from "../api/client";
 import { BookmarksTab } from "../components/Bookmarks";
 import { ReaderNav } from "../components/reader-nav";
-import { btn } from "../components/ui";
+import { ReaderSettings } from "../components/reader-settings";
+import { Button } from "@/components/ui/button";
 import { useProgressSaver, type ReaderProps } from "../lib/useProgress";
 
 // Vite 原生 worker 语法;pdfjs v5 要求 module worker
@@ -124,70 +125,84 @@ export default function PdfReader({ book, initialLocator, initialPercent }: Read
 
   if (err)
     return (
-      <div className="grid h-full place-items-center p-8 text-center">
+      <div className="bg-muted grid h-full place-items-center p-8 text-center">
         <div>
-          <p className="mb-3 text-red-400">{err}</p>
-          <button className={btn} onClick={() => setNonce((x) => x + 1)}>
+          <p className="text-destructive mb-3">{err}</p>
+          <Button variant="secondary" onClick={() => setNonce((x) => x + 1)}>
             重试
-          </button>
+          </Button>
         </div>
       </div>
     );
-  if (num === 0) return <div className="grid h-full place-items-center text-stone-500">PDF 加载中…</div>;
+  if (num === 0) return <div className="text-muted-foreground grid h-full place-items-center">PDF 加载中…</div>;
 
   return (
     <div
       tabIndex={0}
       onKeyDown={onKey}
       aria-label="PDF 阅读器,可用左右方向键翻页"
-      className="relative grid h-full grid-rows-[1fr_auto] focus:outline-none"
+      className="relative grid h-full grid-rows-[1fr_auto] bg-background text-foreground focus:outline-none focus-visible:outline-hidden"
     >
-      <div ref={wrapRef} className="flex min-h-0 items-start justify-center overflow-y-auto bg-stone-900/70 p-4">
-        <canvas ref={canvasRef} className="max-w-3xl rounded-md shadow-2xl ring-1 ring-stone-700/50" />
+      <div ref={wrapRef} className="bg-muted/50 flex min-h-0 items-start justify-center overflow-y-auto p-4">
+        <canvas ref={canvasRef} className="ring-border max-w-3xl rounded-md shadow-2xl ring-1" />
       </div>
-      <div className="flex items-center justify-center gap-2 border-t border-stone-800/80 px-4 py-2 text-sm">
-        <button
-          className={btn + " inline-flex items-center gap-0.5"}
+      <ReaderSettings
+        left={
+          <>
+            <Button
+              variant="ghost"
+              size="sm"
+              className="gap-0.5"
               disabled={page === 0}
               onClick={() => setPage(0)}
               aria-label="第一页"
             >
               <ChevronsLeft size={14} /> 首页
-        </button>
-        <button
-          className={btn + " inline-flex items-center gap-0.5"}
+            </Button>
+            <Button
+              variant="ghost"
+              size="sm"
+              className="gap-0.5"
               disabled={page === 0}
               onClick={() => setPage((p) => Math.max(0, p - 1))}
             >
               <ChevronLeft size={14} /> 上一页
-        </button>
-        <span className="min-w-16 text-center tabular-nums text-stone-400">
+            </Button>
+            <span className="min-w-16 text-center text-muted-foreground tabular-nums">
               {page + 1}/{num}
             </span>
-        <button
-          className={btn + " inline-flex items-center gap-0.5"}
+            <Button
+              variant="ghost"
+              size="sm"
+              className="gap-0.5"
               disabled={page >= num - 1}
               onClick={() => setPage((p) => Math.min(num - 1, p + 1))}
             >
               下一页 <ChevronRight size={14} />
-        </button>
-        <button
-          className={btn + " inline-flex items-center gap-0.5"}
+            </Button>
+            <Button
+              variant="ghost"
+              size="sm"
+              className="gap-0.5"
               disabled={page >= num - 1}
               onClick={() => setPage(num - 1)}
               aria-label="最后一页"
             >
               <ChevronsRight size={14} /> 末页
-        </button>
-        <button
-          className="rd-btn inline-flex items-center gap-1.5"
+            </Button>
+            <Button
+              variant="ghost"
+              size="sm"
+              className="gap-1.5"
               aria-expanded={nav}
               aria-controls="reader-nav"
               onClick={() => setNav((v) => !v)}
             >
               <PanelLeft size={14} /> 导航
-        </button>
-      </div>
+            </Button>
+          </>
+        }
+      />
       {nav && (
         <ReaderNav
           tab="bm"