:root{--bg:#f4f6f8;--card:#fff;--ink:#1e2a33;--muted:#6b7a86;--acc:#0b6e99;--acc2:#0a5a7d;--line:#dfe5ea}
*{box-sizing:border-box}html{scroll-behavior:smooth}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;background:var(--bg);color:var(--ink);line-height:1.55}
header.top{background:var(--acc);color:#fff;position:sticky;top:0;z-index:10}
header.top .in{max-width:1100px;margin:0 auto;padding:10px 18px;display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap}
header.top a{color:#fff;text-decoration:none}
header.top .brand{font-weight:700;font-size:16px}
nav.main a{margin-left:14px;font-size:14px;opacity:.9}nav.main a:hover{opacity:1;text-decoration:underline}
main{max-width:1100px;margin:0 auto;padding:22px 18px;display:grid;grid-template-columns:260px 1fr;gap:24px}
main.single{grid-template-columns:1fr}
aside.toc{position:sticky;top:64px;align-self:start;max-height:calc(100vh - 80px);overflow:auto;background:var(--card);border:1px solid var(--line);border-radius:12px;padding:14px;font-size:13px}
aside.toc summary{cursor:pointer;list-style:none;margin-bottom:6px}aside.toc summary::-webkit-details-marker{display:none}@media(max-width:900px){aside.toc summary::after{content:' ▾';color:var(--muted)}}
aside.toc ul{list-style:none;padding-left:0;margin:0}aside.toc li{margin:4px 0}aside.toc li li{padding-left:12px}
aside.toc a{color:var(--ink);text-decoration:none}aside.toc a:hover{color:var(--acc)}
article{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:28px 32px;min-width:0}
article h1{font-size:26px;margin-top:0}article h2{font-size:21px;margin-top:2em;padding-top:.4em;border-top:1px solid var(--line);color:var(--acc2)}
article h3{font-size:17px;margin-top:1.6em}article h4{font-size:15px}
article p,article li{font-size:16px}article li{margin:.3em 0}
article table{border-collapse:collapse;width:100%;font-size:14px;margin:1em 0;display:block;overflow-x:auto}
article th,article td{border:1px solid var(--line);padding:6px 9px;text-align:left;vertical-align:top}article th{background:#eef3f6}
article code{background:#eef3f6;padding:1px 5px;border-radius:4px;font-size:90%}
article blockquote{border-left:4px solid var(--acc);margin:1em 0;padding:.4em 1em;background:#f7fafc;color:var(--muted)}
.player{background:#eef3f6;border-radius:10px;padding:12px 14px;margin:0 0 18px;display:flex;align-items:center;gap:12px;flex-wrap:wrap}
.player audio{flex:1;min-width:240px}.player a{font-size:13px}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px;margin:18px 0}
.card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:18px;text-decoration:none;color:var(--ink);display:block;transition:box-shadow .15s}
.card:hover{box-shadow:0 4px 14px rgba(0,0,0,.08)}.card h3{margin:0 0 6px;color:var(--acc)}.card p{margin:0;font-size:14px;color:var(--muted)}
.chapters{list-style:none;padding:0}.chapters li{background:var(--card);border:1px solid var(--line);border-radius:10px;padding:12px 16px;margin:8px 0;display:flex;justify-content:space-between;align-items:center;gap:10px;flex-wrap:wrap}
.chapters a{text-decoration:none;color:var(--ink);font-weight:500}.chapters .dur{font-size:13px;color:var(--muted)}
.btn{display:inline-block;background:var(--acc);color:#fff;padding:8px 14px;border-radius:8px;text-decoration:none;font-size:14px}
.btn.sec{background:#e9eef2;color:var(--ink)}
footer{text-align:center;color:var(--muted);font-size:12px;padding:24px}
.tag{display:inline-block;background:#e3eef5;color:var(--acc2);font-size:11px;padding:1px 7px;border-radius:10px;vertical-align:middle;margin-right:4px}.q{border-bottom:1px solid var(--line);padding:10px 0 14px}.q ul.opts{list-style:none;padding-left:0}.q ul.opts li{padding:6px 10px;margin:4px 0;background:#f7fafc;border-radius:8px;font-size:15px}.q details{font-size:14px;color:var(--acc)}.q details summary{cursor:pointer}
.prevnext{display:flex;justify-content:space-between;gap:12px;margin-top:28px;flex-wrap:wrap}
@media(max-width:900px){main{grid-template-columns:1fr}aside.toc{position:static;max-height:none}article{padding:20px 18px}nav.main a{margin-left:10px}}