:root{color-scheme:light;--ink:#302b37;--muted:#65616e;--line:#e6e1e9;--paper:#fcfaf9;--blue:#2b6387}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:15px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}a{color:var(--blue);text-decoration:none}a:hover{text-decoration:underline}button,input,select{font:inherit}button,select{cursor:pointer}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid #85abdf;outline-offset:3px}header{border-bottom:1px solid var(--line);background:#fff}nav,main,footer{max-width:1240px;margin:auto;padding:22px 28px}nav{display:flex;align-items:center;justify-content:space-between;gap:18px}.brand{font:20px Georgia,serif;color:var(--ink)}.languages{display:flex;gap:3px;padding:4px;border:1px solid var(--line);border-radius:30px}.languages :is(button,a){border:0;padding:5px 12px;border-radius:24px;background:transparent;color:var(--muted)}.languages :is(button,a)[aria-pressed=true]{background:var(--blue);color:white}.hero{padding:42px 0 25px}.eyebrow{font:11px ui-monospace,monospace;letter-spacing:.14em;color:var(--muted)}h1{font:48px/1.1 Georgia,serif;margin:16px 0 18px;letter-spacing:-.03em}html[lang=zh-CN] h1{font-family:inherit;font-weight:550;font-size:40px;letter-spacing:0}.intro{max-width:800px;color:var(--muted);font-size:17px}.stats{display:grid;grid-template-columns:repeat(4,1fr);margin:28px 0 22px;border-top:1px solid var(--ink);border-bottom:1px solid var(--line)}.stats>div{padding:16px 18px;border-right:1px solid var(--line)}.stats>div:first-child{padding-left:0}.stats>div:last-child{border:0}.stats strong{font:35px Georgia,serif;display:block}.stats span{color:var(--muted);font-size:12px}.note{color:var(--muted);font-size:13px;max-width:980px}.source-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:20px 0 38px}.source-card{border:1px solid var(--line);border-radius:14px;background:#fff;padding:16px 18px}.source-card h3{font-size:16px;margin:0 0 5px}.source-card p{margin:5px 0;color:var(--muted);font-size:13px}.source-card .links{display:flex;gap:12px;font-size:12px;margin-top:10px}.chip{font:11px ui-monospace,monospace;background:#edf1f5;border-radius:5px;padding:3px 7px;display:inline-block}.toolbar{display:flex;gap:10px;flex-wrap:wrap;padding:18px 0;border-top:1px solid var(--line)}input,select,.outline{border:1px solid #cbd2dc;border-radius:9px;background:#fff;color:var(--ink);padding:9px 12px}.toolbar input{flex:1;min-width:220px}.toolbar select{max-width:240px}.counts{display:flex;justify-content:space-between;align-items:center;margin:10px 0 16px;color:var(--muted);font-size:13px}.task-list{display:grid;grid-template-columns:1fr 1fr;gap:16px}.task-card{background:#fff;border:1px solid var(--line);border-radius:15px;padding:21px;min-width:0}.task-meta{display:flex;gap:6px;align-items:center;flex-wrap:wrap;font-size:11px;color:var(--muted)}.task-card h3{font-size:13px;font-weight:500;color:var(--muted);margin:15px 0 7px;overflow-wrap:anywhere}.instruction{font-size:15px;line-height:1.65;white-space:pre-wrap;overflow-wrap:anywhere;margin:0 0 16px}.task-links{display:flex;flex-wrap:wrap;gap:12px;font-size:13px}.task-card details{margin-top:16px;border-top:1px solid var(--line);padding-top:12px}summary{cursor:pointer;color:var(--muted);font-size:13px}pre{font:11px/1.6 ui-monospace,monospace;white-space:pre-wrap;overflow-wrap:anywhere;max-height:360px;overflow:auto;padding:15px;background:#f4f6f8;border-radius:8px}.status{color:#557266;font-size:12px;margin-top:10px}.pager{display:flex;align-items:center;justify-content:center;gap:18px;padding:30px}button:disabled{opacity:.45;cursor:default}.empty{grid-column:1/-1;text-align:center;color:var(--muted);padding:70px 10px}footer{color:var(--muted);font-size:12px;border-top:1px solid var(--line)}.downloads{display:flex;gap:15px;align-items:center;flex-wrap:wrap;margin-top:16px}.downloads button{background:var(--blue);color:#fff;border:0;border-radius:24px;padding:9px 18px}.audit{margin:20px 0}.audit p{font-size:13px;color:var(--muted)}
@media(max-width:760px){nav,main,footer{padding-left:18px;padding-right:18px}.brand{font-size:16px}nav{align-items:flex-start}.languages :is(button,a){font-size:12px;padding:4px 8px}h1{font-size:36px}html[lang=zh-CN] h1{font-size:30px}.hero{padding-top:25px}.stats{grid-template-columns:1fr 1fr}.stats>div{padding-left:0;border:0}.stats strong{font-size:30px}.source-grid{grid-template-columns:1fr 1fr}.task-list{grid-template-columns:1fr}.toolbar select{flex:1;min-width:120px;max-width:none}.counts{align-items:flex-start;gap:15px}.source-card{padding:13px}.source-card .links{flex-wrap:wrap;gap:8px}}
@media(max-width:420px){.source-grid{grid-template-columns:1fr}nav{flex-wrap:wrap}.languages{margin-left:auto}.task-card{padding:17px}}
.active-scope{display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap;background:#edf6fb;border:1px solid #c7e1ed;border-radius:12px;padding:12px 16px;color:var(--blue);font-size:14px}.active-scope[hidden]{display:none}.active-scope a{font-weight:600;white-space:nowrap}

.languages a{text-decoration:none;display:inline-flex;align-items:center}.languages a[aria-current="page"]{background:var(--blue);color:#fff}.source-breadcrumb{font-size:13px;color:var(--muted);margin:14px 0}.source-hero{padding-top:16px}.source-facts{display:grid;grid-template-columns:1fr 1fr;gap:30px}.source-facts h2,.source-categories h2,.source-task-index h2{font-size:23px;font-weight:550;margin:18px 0 12px}.source-facts p{line-height:1.8}.source-pin{font-size:13px;line-height:1.9;overflow-wrap:anywhere}.source-primary{display:inline-block;padding:10px 17px;border-radius:24px;background:var(--blue);color:#fff}.source-category-list{display:flex;flex-wrap:wrap;gap:7px;margin:15px 0 30px}.source-task-index{margin-top:32px}.source-task{border:1px solid var(--line);background:white;border-radius:12px;margin:10px 0}.source-task>summary{display:grid;grid-template-columns:16px minmax(120px,.65fr) minmax(0,2fr);gap:12px;padding:16px;align-items:baseline;color:var(--ink);font-size:14px;list-style:none}.source-task>summary::-webkit-details-marker{display:none}.source-task>summary:before{content:'+';color:var(--blue);font-size:18px}.source-task[open]>summary:before{content:'−'}.source-task-id{font:11px/1.65 ui-monospace,monospace;overflow-wrap:anywhere;color:var(--muted)}.source-task-body{padding:18px 22px;border-top:1px solid var(--line)}.source-task[open]{border-color:#b9d6e6}.source-task-body .task-links{gap:12px 20px}.reading-nav{justify-content:flex-start;padding:30px 0 0;flex-wrap:wrap;font-size:13px}.source-task-index>.note{max-width:80ch}@media(max-width:700px){.source-facts{grid-template-columns:1fr;gap:8px}.source-task>summary{grid-template-columns:16px minmax(0,1fr);gap:7px 12px}.source-task>summary>span:last-child{grid-column:2}.source-task-body{padding:16px}.source-primary{font-size:13px}.source-hero h1{font-size:32px}}

.source-task>summary>span{min-width:0;overflow-wrap:anywhere}

.source-level-section{margin:32px 0}.source-level-section h2{font-size:23px;font-weight:550}
.source-levels{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
.source-level-card{--accent:#70d6ff;display:flex;flex-direction:column;gap:15px;padding:20px;border:1px solid var(--line);border-top:4px solid var(--accent);border-radius:10px;background:#fff;text-decoration:none;color:var(--ink)}
.source-level-card:nth-child(2){--accent:#ff70a6}.source-level-card:nth-child(3){--accent:#ff9770}
.source-level-card strong{font:38px/1.1 Georgia,serif}.source-level-card span:last-child{font-size:12px;color:var(--blue)}
.source-task:target{border-color:var(--blue);scroll-margin-top:20px}.source-level-card:focus-visible{outline:2px solid var(--blue);outline-offset:3px}
@media(max-width:600px){.source-levels{grid-template-columns:1fr}.source-level-card{display:grid;grid-template-columns:1fr auto;align-items:center}.source-level-card span:last-child{grid-column:1/-1}}