:root{--ink:#14213a;--muted:#55627a;--line:#d9e0ea;--bg:#f6f8fb;--card:#fff;--accent:#0b6e7f;--accent-d:#084f5c;--tint:#e4f2f4;--max:1120px}
@media(prefers-color-scheme:dark){:root{--ink:#e8edf5;--muted:#9aa8bf;--line:#2a3a55;--bg:#0e1626;--card:#15203a;--accent:#5cc3d3;--accent-d:#8fdbe7;--tint:#12303a}}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:16px}
body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.65 "IBM Plex Sans",system-ui,sans-serif}
h1,h2,h3{font-family:"Source Serif 4",Georgia,serif;line-height:1.2;margin:0 0 .5em}
h1{font-size:clamp(2.2rem,5vw,3.4rem);letter-spacing:-.01em}
h2{font-size:1.65rem;margin-top:2.4em;padding-top:1em;border-top:1px solid var(--line)}
h3{font-size:1.15rem}
a{color:var(--accent-d)}
a:focus-visible,button:focus-visible{outline:3px solid var(--accent);outline-offset:2px}
.skip{position:absolute;left:-999px}.skip:focus{left:8px;top:8px;background:var(--card);padding:8px;z-index:9}
.wrap{max-width:var(--max);margin:0 auto;padding:0 20px}
.strip{background:var(--ink);color:var(--bg);font-size:.85rem;padding:6px 0}
.strip .wrap{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}
header.site{background:var(--card);border-bottom:1px solid var(--line)}
header.site .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;padding-top:14px;padding-bottom:14px}
.brand{font:700 1.3rem "Source Serif 4",Georgia,serif;text-decoration:none;color:var(--ink)}
.brand small{display:block;font:400 .8rem "IBM Plex Sans",sans-serif;color:var(--muted)}
nav.main{display:flex;gap:20px;flex-wrap:wrap}
nav.main a{color:var(--ink);text-decoration:none;font-weight:500}
nav.main a:hover{text-decoration:underline}
.btn{display:inline-block;background:var(--accent);color:#fff;padding:10px 18px;border-radius:6px;text-decoration:none;font-weight:600}
.btn:hover{background:var(--accent-d)}
.topics{background:var(--tint);border-bottom:1px solid var(--line);font-size:.92rem}
.topics .wrap{display:flex;gap:6px 22px;flex-wrap:wrap;padding-top:8px;padding-bottom:8px}
.topics a{color:var(--accent-d);text-decoration:none}
.crumb{color:var(--muted);font-size:.9rem;margin:28px 0 8px}
.brief{background:var(--card);border:1px solid var(--line);border-left:5px solid var(--accent);padding:20px 24px;margin:20px 0;border-radius:4px}
.brief h2{border:0;margin:0 0 .3em;padding:0;font-size:1.2rem}
.note{font-size:.92rem;color:var(--muted)}
.layout{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:48px;align-items:start}
.toc{background:var(--card);border:1px solid var(--line);border-radius:4px;padding:16px 22px;margin:24px 0}
.toc ol{columns:2;margin:.4em 0 0;padding-left:1.3em}
.chain{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin:20px 0;font-size:.92rem}
.chain a{background:var(--tint);border-radius:99px;padding:3px 14px;text-decoration:none}
.chain span{color:var(--muted)}
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px;margin:16px 0}
.card{display:block;background:var(--card);border:1px solid var(--line);border-radius:4px;padding:16px 18px;text-decoration:none;color:var(--ink)}
.card:hover{border-color:var(--accent)}
.card small{display:block;color:var(--accent-d);font-size:.82rem;margin-bottom:4px}
.card strong{font-family:"Source Serif 4",Georgia,serif;font-size:1.08rem;display:block}
.card span{display:block;font-size:.93rem;color:var(--muted);margin-top:4px}
.card em{display:block;font-style:normal;color:var(--accent-d);font-weight:600;font-size:.9rem;margin-top:8px}
.feature{background:var(--card);border:2px solid var(--accent);border-radius:6px;padding:24px;margin:16px 0}
.feature .tag{display:inline-block;background:var(--accent);color:#fff;font-size:.8rem;padding:2px 10px;border-radius:99px;margin-bottom:10px}
table{width:100%;border-collapse:collapse;font-size:.95rem;margin:12px 0 18px}
th,td{text-align:left;padding:8px 10px;border-bottom:1px solid var(--line);vertical-align:top}
th{width:28%;color:var(--muted);font-weight:500}
details{background:var(--card);border:1px solid var(--line);border-radius:4px;padding:12px 18px;margin:10px 0}
summary{cursor:pointer;font-weight:600}
aside.side{position:sticky;top:16px;background:var(--card);border:1px solid var(--line);border-radius:4px;padding:20px;margin-top:24px}
aside.side dt{color:var(--muted);font-size:.85rem;margin-top:12px}
aside.side dd{margin:0;font-weight:500}
.cite{background:var(--card);border:1px dashed var(--line);padding:14px 18px;font-size:.93rem;word-break:break-word}
footer{margin-top:64px;background:var(--ink);color:var(--bg);padding:32px 0;font-size:.92rem}
footer a{color:var(--bg)}
footer nav{display:flex;gap:18px;flex-wrap:wrap;margin:10px 0}
@media(max-width:900px){.layout{grid-template-columns:1fr}aside.side{position:static}.toc ol{columns:1}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}

.ckbar{position:fixed;left:0;right:0;bottom:0;z-index:50;background:var(--card);border-top:2px solid var(--accent);padding:14px 20px;display:flex;gap:16px;align-items:center;justify-content:space-between;flex-wrap:wrap;font-size:.92rem;box-shadow:0 -4px 16px rgba(0,0,0,.12)}
.ckbar p{margin:0;max-width:720px}.ckbar div{display:flex;gap:10px}
.ckbar button{font:600 .92rem "IBM Plex Sans",sans-serif;padding:8px 16px;border-radius:6px;cursor:pointer;border:1px solid var(--accent);background:var(--card);color:var(--accent-d)}
.ckbar .ckyes{background:var(--accent);color:#fff}
.cklink{background:none;border:0;color:var(--bg);text-decoration:underline;cursor:pointer;font:inherit;padding:0}