/* tokens:begin */
/* 全站设计令牌（唯一来源）。index.html 与 public/public.css 里同名标记之间的内容由
   deploy/sync_design.py 从这里复制；tests/test_design_tokens.py 断言三处一字不差。
   旧名（--fg/--panel/--soft/--leaf/--amber…）先做别名，替换完成后删除。*/
:root{color-scheme:light;
--bg:#f7f8fc;--surface:#fff;--surface-2:#f1f2f8;--line:#e3e6f2;--line-strong:#cbd0e6;
--ink:#1c1f2e;--ink-2:#454a63;--muted:#626784;
--accent:#5b5bd6;--accent-strong:#4646c2;--accent-soft:#eceefc;--accent-ink:#3c3cb0;--on-accent:#fff;
--ok:#1f7a50;--ok-soft:#e6f6ee;--warn:#8a5309;--warn-soft:#fff3d6;--err:#b03a4b;--err-soft:#ffecee;--hl:#ffe58a;--hl-soft:#fffcf0;
--bili:#fb7299;--yt:#e53935;
--r-sm:8px;--r-md:12px;--r-lg:16px;--r-pill:999px;
--sh-sm:0 1px 2px rgba(28,31,46,.06);--sh-md:0 8px 24px rgba(28,31,46,.1);
--fs-1:12px;--fs-2:13px;--fs-3:14px;--fs-4:16px;--fs-5:18px;--fs-6:22px;--fs-7:28px;--fs-8:36px;
--font:"Segoe UI","PingFang SC","Microsoft YaHei",system-ui,sans-serif;--mono:ui-monospace,"SFMono-Regular",Consolas,"Microsoft YaHei",monospace;
--measure:720px;--side-w:300px;--top-h:64px;--page-w:1180px;
--panel:var(--surface);--fg:var(--ink);--accent-hover:var(--accent-strong);--soft:var(--accent-soft);--active:var(--accent-soft);
--hit:var(--hl);--hitline:var(--hl-soft);--shadow:var(--sh-sm);--shadow-sm:var(--sh-sm);--radius:var(--r-lg);
--leaf:var(--ok);--leaf-soft:var(--ok-soft);--leaf-ink:var(--ok);--amber:var(--warn);--amber-soft:var(--warn-soft);--amber-ink:var(--warn);
--cta-bg:#3a3ab4;--cta-ink:#fff;--cta-soft:rgba(255,255,255,.14)}
/* tokens:end */
/* shell:begin */
/* 全站外壳（唯一来源）：头部、页脚、按钮、语言开关。首页 / 工作台（index.html）与公共页
   （public/shell.html + public.css）用同一份标记结构与同一份样式；改这里，再跑
   deploy/sync_design.py 同步到两处。状态：默认 = 游客；.hp-auth-header = 已登录。*/
/* 头部不吸顶：吸顶会让首页预览卡的键盘切换触发滚动锚定回滚（homepage_tabs.py），阅读页的吸顶工具条在 PR-38 单独做。 */
.site-top{position:relative;z-index:40;height:var(--top-h);max-width:none;margin:0;padding:0 max(24px,calc((100vw - var(--page-w))/2));display:flex;align-items:center;gap:20px;background:var(--surface);border-bottom:1px solid var(--line)}
.site-top .brand{display:inline-flex;align-items:center;gap:10px;flex:none;color:var(--ink);font-family:var(--font);text-decoration:none!important}
.site-top .brand-mark{display:flex;align-items:center;justify-content:center;gap:3px;width:32px;height:32px;border-radius:9px;background:var(--accent);box-shadow:none}
.site-top .brand-mark i{display:block;width:3px;height:14px;border-radius:3px;background:#fff}
.site-top .brand-mark i:nth-child(2){height:20px}.site-top .brand-mark i:nth-child(3){height:10px}
.site-top .brand-name{font-size:20px;font-weight:700;letter-spacing:-.02em;line-height:1}
.site-top .brand-note{margin-left:2px;padding-left:12px;border-left:1px solid var(--line);color:var(--muted);font-size:var(--fs-2);line-height:1.2}
.site-top .topnav{display:flex;align-items:center;gap:6px;margin-left:auto;min-width:0;font-size:var(--fs-3)}
.site-top .account-nav{display:flex;align-items:center;gap:2px;margin-right:auto;min-width:0}
.site-top .account-nav .text-btn{padding:8px 10px;border-radius:var(--r-sm);color:var(--ink-2);font-size:var(--fs-3);white-space:nowrap}
.site-top .account-nav .text-btn:hover{background:var(--surface-2);color:var(--ink)}
.site-top .account-nav .text-btn.on{color:var(--accent-ink);font-weight:600}
.site-top .account-name{max-width:140px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;color:var(--ink);font-size:var(--fs-1)}
.site-top .text-btn{padding:8px 10px;border-radius:var(--r-sm);color:var(--ink-2);white-space:nowrap}
.site-top .text-btn:hover{background:var(--surface-2);color:var(--ink)}
.ui-link{display:inline-flex;align-items:center;padding:8px 10px;border-radius:var(--r-sm);color:var(--ink-2);font-size:var(--fs-3);text-decoration:none;white-space:nowrap}
.ui-link:hover{background:var(--surface-2);color:var(--ink);text-decoration:none}
.ui-lang{display:inline-flex;flex:none;gap:2px;padding:3px;border-radius:var(--r-pill);background:var(--surface-2)}
.ui-lang>button,.ui-lang>a{display:inline-flex;align-items:center;min-height:30px;padding:0 12px;border:0;border-radius:var(--r-pill);background:transparent;color:var(--muted);font:600 var(--fs-2)/1.4 var(--font);text-decoration:none;white-space:nowrap;cursor:pointer}
.ui-lang>button[aria-pressed="true"],.ui-lang>a[aria-current="page"]{background:var(--surface);color:var(--ink);box-shadow:var(--sh-sm)}
.ui-lang>button:hover,.ui-lang>a:hover{color:var(--ink-2);text-decoration:none}
.ui-btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:38px;padding:7px 14px;border:1px solid var(--line-strong);border-radius:var(--r-sm);background:var(--surface);color:var(--ink);font:600 var(--fs-3)/1.4 var(--font);text-decoration:none;white-space:nowrap;cursor:pointer}
.ui-btn:hover{background:var(--surface-2);text-decoration:none}
.ui-btn-primary{border-color:var(--accent);background:var(--accent);color:var(--on-accent)}
.ui-btn-primary:hover{border-color:var(--accent-strong);background:var(--accent-strong);color:var(--on-accent)}
.ui-btn-ghost{border-color:transparent;background:transparent;color:var(--ink-2)}
.ui-btn-ghost:hover{background:var(--surface-2);color:var(--ink)}
.ui-btn small{margin-left:2px;padding:1px 5px;border-radius:5px;background:#fff;color:var(--err);font-size:10px;font-weight:700;line-height:1.4}
.site-top .hide{display:none!important}
@media(max-width:1100px){.site-top .brand-note{display:none}}
@media(max-width:640px){.site-top{--top-h:56px;padding:0 12px;gap:8px}
.site-top .brand-mark{width:28px;height:28px;border-radius:8px}.site-top .brand-name{font-size:18px}
.site-top .topnav{gap:4px}.site-top .ui-link{display:none}.site-top .text-btn{display:none}
.site-top .ui-btn{min-height:36px;padding:6px 10px;font-size:var(--fs-2)}
.ui-lang>button,.ui-lang>a{min-height:28px;padding:0 9px;font-size:var(--fs-1)}
/* 已登录的手机头部仍是一行 56px：头部高度在登录态判定前后不变，深链首屏才没有位移（CLS）。 */
.site-top.hp-auth-header .brand-name{display:none}
.site-top.hp-auth-header .account-nav{gap:0;margin-right:auto;overflow:auto;scrollbar-width:none}
.site-top.hp-auth-header .account-nav .text-btn{display:inline-flex;padding:6px 5px;font-size:var(--fs-1)}
.site-top.hp-auth-header .ui-btn{padding:6px 8px;font-size:var(--fs-1)}
.site-top.hp-auth-header .ui-lang>button{padding:0 7px}
.site-top .account-name{display:none}}
/* 已登录手机头部放不下两段式语言开关：只显示"另一种语言"那一段，当切换按钮用。 */
@media(max-width:640px){.site-top.hp-auth-header .ui-lang>button[aria-pressed="true"]{display:none}}
@media(max-width:640px){:lang(en) .site-top.hp-auth-header .account-nav .text-btn{font-size:11px;padding:6px 4px}:lang(en) .site-top.hp-auth-header .ui-btn{font-size:11px;padding:6px 7px}}
@media(max-width:360px){.site-top.hp-auth-header .account-nav .text-btn{padding:6px 3px}.site-top.hp-auth-header .ui-btn{padding:6px 6px}}
@media(max-width:480px){.site-top{gap:6px}.site-top .ui-btn{padding:6px 8px}.ui-lang>button,.ui-lang>a{padding:0 8px}}
@media(max-width:400px){.site-top{padding:0 8px}.site-top .brand-name{font-size:16px}.ui-lang>button,.ui-lang>a{padding:0 7px}}
@media(max-width:360px){.site-top .brand-name{display:none}}
.site-foot{margin:0;padding:44px max(24px,calc((100vw - var(--page-w))/2)) 24px;background:var(--surface);border-top:1px solid var(--line);color:var(--ink-2);font-family:var(--font);font-size:var(--fs-3);line-height:1.7}
.site-foot .foot-grid{display:grid;grid-template-columns:1.4fr repeat(4,minmax(0,1fr));gap:28px 24px}
.site-foot .foot-logo{display:inline-flex;align-items:center;gap:10px;color:var(--ink);font-size:20px;font-weight:700;letter-spacing:-.02em;text-decoration:none}
.site-foot .foot-logo .brand-mark{display:flex;align-items:center;justify-content:center;gap:3px;width:30px;height:30px;border-radius:8px;background:var(--accent)}
.site-foot .foot-logo .brand-mark i{display:block;width:3px;height:13px;border-radius:3px;background:#fff}
.site-foot .foot-logo .brand-mark i:nth-child(2){height:18px}.site-foot .foot-logo .brand-mark i:nth-child(3){height:9px}
.site-foot .foot-brand p{margin:12px 0 0;max-width:34ch;color:var(--ink-2)}
.site-foot h4{margin:0 0 8px;color:var(--muted);font-size:var(--fs-1);font-weight:700;letter-spacing:.06em}
.site-foot .foot-col a,.site-foot .foot-col button{display:block;width:100%;padding:4px 0;border:0;background:none;color:var(--ink-2);font:inherit;text-align:left;text-decoration:none;cursor:pointer}
.site-foot .foot-col a:hover,.site-foot .foot-col button:hover{color:var(--ink);text-decoration:underline;text-underline-offset:3px}
.site-foot .foot-bottom{display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px 16px;margin-top:32px;padding-top:16px;border-top:1px solid var(--line);color:var(--muted);font-size:var(--fs-2)}
.site-foot .foot-bottom p{margin:0}
@media(max-width:900px){.site-foot .foot-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.site-foot .foot-brand{grid-column:1/-1}}
@media(max-width:640px){.site-foot{padding-top:32px}.site-foot .foot-grid{gap:22px 16px}}
/* shell:end */

*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.75 var(--font)}a{color:var(--accent);text-underline-offset:3px}button,input{font:inherit}a:focus-visible,button:focus-visible,input:focus-visible{outline:3px solid var(--accent);outline-offset:3px}a,button,input{touch-action:manipulation}.skip{position:absolute;top:-100px;padding:12px;background:#fff;z-index:10}.skip:focus{top:6px}main{width:min(1060px,100% - 40px);margin:auto}.button,button{display:inline-flex;align-items:center;justify-content:center;min-height:48px;padding:11px 20px;border-radius:10px;border:1px solid var(--accent);background:var(--accent);color:#fff;text-decoration:none;font-weight:650;cursor:pointer;white-space:normal;text-align:center}.small{min-height:42px;padding:8px 15px}.button.secondary{color:var(--accent);background:#fff}button:disabled{cursor:wait;opacity:.65}main{padding:54px 0 20px}.eyebrow{font-size:14px;color:var(--accent);font-weight:750;letter-spacing:.06em}h1{font-size:clamp(30px,5vw,52px);line-height:1.2;letter-spacing:-1.5px;max-width:860px;margin:14px 0 24px}h2{font-size:27px;line-height:1.35;margin:0 0 20px}h3{font-size:19px;line-height:1.45;margin:0 0 10px}.lead{font-size:20px;color:var(--muted);max-width:820px}.muted,.note{color:var(--muted)}.note{font-size:14px}.intro{margin-bottom:35px}.input-panel,section.panel,.sample{border:1px solid var(--line);background:#fff;border-radius:18px;padding:28px}.input-panel{margin:30px 0}.input-panel label{display:block;font-weight:650;margin-bottom:10px}.input-row{display:flex;gap:12px}.input-row input{flex:1;min-width:0;padding:14px;border:1px solid #bec2d6;border-radius:10px;color:var(--ink);background:#fff}.input-panel p{margin:12px 0 0}.status:empty{display:none}.status{color:#a42138;font-weight:600}.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:22px}.grid>*{min-width:0}.card{border:1px solid var(--line);background:#fff;border-radius:14px;padding:24px}.card p:last-child{margin-bottom:0}.number{display:inline-flex;align-items:center;justify-content:center;background:var(--soft);color:var(--accent);font-weight:700;width:36px;height:36px;border-radius:50%;margin-bottom:16px}section{margin:40px 0}.sample{background:var(--soft)}blockquote{margin:20px 0;padding:0 0 0 18px;border-left:3px solid #a8a3ef}blockquote p{margin:8px 0}.sample cite{font-style:normal;font-size:14px;color:var(--muted)}code,pre{font:14px/1.7 ui-monospace,Consolas,monospace}pre{overflow-wrap:anywhere;white-space:pre-wrap;background:#fff;padding:20px;border-radius:12px;border:1px solid var(--line)}.link-list{display:flex;gap:16px;flex-wrap:wrap}.table-wrap{overflow-x:auto}table{width:100%;border-collapse:collapse;text-align:left}th,td{padding:12px 10px;border-bottom:1px solid var(--line);vertical-align:top}th{font-size:14px}.entry{scroll-margin-top:20px;border-top:1px solid var(--line);padding-top:25px;margin-top:28px}.entry time{font-size:14px;color:var(--muted)}.entry h2{margin-top:12px}.entry:target{border-left:4px solid var(--accent);padding-left:18px}p,li,h1,h2,h3,a{overflow-wrap:anywhere}li{margin:8px 0}ul,ol{padding-left:24px}.empty{padding:70px 0;max-width:650px}
/* CJK closing punctuation at the end of a line keeps its full width. With Chrome's default (text-spacing-trim: normal)
   a line ending in "？》" fits only if the bracket counts as half-width, yet the bracket is laid out full-width and the
   line runs 7px past its box (/zh/youtube-transcript at 320px). space-all is the setting of browsers without the feature. */
body{text-spacing-trim:space-all}
@media(max-width:700px){main{width:calc(100% - 32px)}main{padding-top:32px}h1{letter-spacing:-.8px}.lead{font-size:18px}.input-row{flex-direction:column}.input-row button{width:100%}.input-panel,section.panel,.sample{padding:20px}.grid{grid-template-columns:1fr;gap:14px}section{margin:30px 0}h2{font-size:23px}.card{padding:20px}.link-list{flex-direction:column;gap:10px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}

.guide-shot{margin:24px 0}.guide-shot img{display:block;width:100%;height:auto;border:1px solid var(--line);border-radius:12px;background:#fff}.guide-shot figcaption{font-size:14px;color:var(--muted);margin-top:10px}.quote-preview{padding:20px;background:#fff;border:1px solid var(--line);border-radius:12px}.quote-preview h3{font-size:20px}.quote-preview h4{font-size:17px}.quote-preview p{overflow-wrap:anywhere}

.faq details{border-top:1px solid var(--line);padding:0 4px 0 0}.faq details:last-child{border-bottom:1px solid var(--line)}.faq summary{font-weight:650;cursor:pointer;padding:17px 0;line-height:1.55}.faq summary:focus-visible{outline:3px solid var(--accent);outline-offset:3px}.faq details p{margin:0 0 16px;color:var(--muted)}

.catalog-card{display:flex;flex-direction:column;gap:10px}.catalog-card.recommended{border:2px solid var(--accent);box-shadow:var(--sh-md)}.catalog-card h3,.catalog-card p{margin:0}.catalog-card ul{flex:1}.catalog-price{display:flex;align-items:baseline;gap:10px;flex-wrap:wrap}.catalog-price strong{font-size:32px;line-height:1.35}.catalog-price s{font-size:14px;color:var(--muted)}.catalog-tags{display:flex;gap:6px;flex-wrap:wrap;min-height:26px}.catalog-tag{font-size:12px;font-weight:650;color:var(--accent);background:var(--soft);border-radius:6px;padding:2px 8px}.catalog-tag.offer{color:#a22433;background:var(--err-soft)}.catalog-offer{background:var(--soft);border-left:4px solid var(--accent);padding:18px 20px;border-radius:10px}.catalog-card .button{margin-top:auto}.catalog-card .note{font-size:13px}
@media(max-width:700px){.catalog-card.recommended{order:-1}.catalog-price strong{font-size:30px}}

.audio-walkthrough figure,.audio-case figure,.yt-case figure{margin:28px 0}.audio-walkthrough img,.audio-case img,.yt-case img{display:block;width:auto;max-width:100%;height:auto;margin:auto;border:1px solid var(--line);border-radius:12px;background:#fff}.audio-walkthrough figcaption,.audio-case figcaption,.yt-case figcaption{margin-top:10px;font-size:13px;line-height:1.7;color:var(--muted)}.audio-case h3,.yt-case h3{margin-top:30px}.audio-case td:first-child{white-space:nowrap}.audio-faq details{padding:18px 0;border-bottom:1px solid var(--line)}.audio-faq summary{font-weight:650;cursor:pointer}.audio-faq details p{margin-bottom:0}
.transcript-meta{color:var(--muted);font-size:15px;overflow-wrap:anywhere}.transcript{max-width:760px}.transcript p{margin:0 0 18px;overflow-wrap:break-word}.transcript .ts{font-variant-numeric:tabular-nums;font-size:14px;margin-right:6px;text-decoration:none;white-space:nowrap}.transcript p:target{background:var(--soft);outline:2px solid var(--soft);border-radius:6px}.attribution p{font-size:14px;color:var(--muted);overflow-wrap:anywhere}.transcript-list{list-style:none;padding:0;margin:0}.transcript-list li{padding:12px 0;border-bottom:1px solid var(--line)}.transcript-list li a{font-weight:650;display:block}.transcript-list .muted{font-size:14px}
.guide-shot.note-shot{max-width:720px;margin-left:auto;margin-right:auto}
/* Address-replacement entry (web/url_entry.py): under the tool-page input, the bookmarklet to drag to the bookmarks
   bar. Phones and touch-only devices get only the tip line: dragging a bookmark is not practical there. */
.bookmarklet-row{display:flex;align-items:center;flex-wrap:wrap;gap:6px 10px}.bookmarklet{display:inline-flex;align-items:center;min-height:34px;padding:5px 12px;border:1px dashed var(--accent);border-radius:8px;background:var(--soft);color:var(--accent);font-weight:650;text-decoration:none;cursor:grab}.bookmarklet:hover{border-style:solid;text-decoration:none}.bookmarklet-hint{color:var(--ink-2)}.bookmarklet-hint:empty{display:none}
@media(max-width:700px),(hover:none){.bookmarklet-row{display:none}}
/* Shared traffic statistics dialog. */
.statistics-dialog{box-sizing:border-box;width:min(540px,calc(100vw - 32px));max-height:calc(100vh - 40px);overflow:auto;padding:24px;border:1px solid var(--line-strong);border-radius:14px;background:var(--surface);color:var(--ink)}
.statistics-dialog h2{margin:0 0 16px;font-size:22px}
.statistics-dialog p{font-size:13px;line-height:1.6;color:var(--muted);margin:8px 0 16px}
.statistics-dialog label{font-weight:600;display:flex;align-items:center;gap:8px}
.statistics-dialog input{width:18px;height:18px;flex:none}
.statistics-dialog>a{display:block;margin:12px 0;font-size:13px;color:var(--accent-ink)}
.statistics-dialog button{padding:8px 16px}
.statistics-dialog [hidden]{display:none}

.catalog-refund{margin:24px 0;padding:20px 24px;border:1px solid var(--accent);border-left:4px solid var(--accent);border-radius:12px;background:var(--soft);min-width:0;overflow-wrap:anywhere}
.catalog-refund h3{margin:0 0 8px;color:var(--accent-ink)}.catalog-refund p{margin:8px 0}.catalog-refund-window{font-weight:750;color:var(--ink)}.catalog-refund-links{display:flex;flex-wrap:wrap;gap:8px 24px;margin-top:12px}.catalog-refund-links a{font-weight:650}
@media(max-width:700px){.catalog-refund{padding:18px}.catalog-refund-links{gap:8px 18px}}