:root{--bg:#f5f7fb;--card:#fff;--ink:#0b1f3a;--mute:#4a5b73;--line:#d9e1ec;--brand:#1d4ed8;--brand-ink:#fff;--accent:#0f766e;--focus:#f59e0b}
@media (prefers-color-scheme:dark){:root:not([data-theme=light]){--bg:#0b1424;--card:#111e33;--ink:#eaf1fb;--mute:#a9b8cc;--line:#25364f;--brand:#5b8cff;--brand-ink:#08111f;--accent:#5eead4}}
*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.55 system-ui,-apple-system,"Segoe UI",Roboto,"Noto Sans",sans-serif}
a{color:var(--brand)}a:focus-visible,button:focus-visible,video:focus-visible{outline:3px solid var(--focus);outline-offset:2px;border-radius:6px}
.skip{position:absolute;left:-999px;top:8px;background:var(--card);padding:8px 12px;border-radius:8px;z-index:10}.skip:focus{left:16px}
.top{display:flex;align-items:center;justify-content:space-between;gap:16px;max-width:1040px;margin:0 auto;padding:14px 16px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;color:var(--ink);text-decoration:none;font-size:1.1rem}.brand img{border-radius:50%}
.top nav a{display:inline-block;padding:8px 14px;border:1px solid var(--line);border-radius:999px;text-decoration:none;color:var(--ink);background:var(--card);min-height:40px}
main{max-width:1040px;margin:0 auto;padding:0 16px 40px}
.hero{padding:20px 0 8px}h1{font-size:clamp(1.7rem,4.5vw,2.6rem);line-height:1.15;margin:.2em 0 .4em}.lead{color:var(--mute);font-size:1.1rem;max-width:60ch;margin:0 0 16px}
.ctas{display:flex;flex-wrap:wrap;gap:12px;margin:16px 0}.btn{display:inline-flex;align-items:center;justify-content:center;min-height:46px;padding:10px 20px;border-radius:12px;border:1px solid var(--line);background:var(--card);color:var(--ink);font-weight:600;text-decoration:none}
.btn.primary{background:var(--brand);color:var(--brand-ink);border-color:var(--brand)}
h2{font-size:1.35rem;margin:0 0 8px}h3{font-size:1.05rem;margin:0 0 4px}
.player{margin:20px 0}.fmt{display:flex;gap:8px;margin:8px 0 12px}.fmt[hidden]{display:none}
.fmt button{min-height:40px;padding:6px 14px;border-radius:999px;border:1px solid var(--line);background:var(--card);color:var(--ink);font:inherit;cursor:pointer}
.fmt button[aria-pressed=true]{background:var(--brand);color:var(--brand-ink);border-color:var(--brand)}
.stage{background:#000;border-radius:14px;overflow:hidden;margin:0 auto;max-width:100%}
.stage[data-fmt="169"]{aspect-ratio:16/9}.stage[data-fmt="916"]{aspect-ratio:9/16;max-width:min(100%,380px)}
.stage video{display:block;width:100%;height:100%;background:#000;object-fit:contain}
.vfail{margin:0;padding:16px;background:var(--card);color:var(--ink)}
.chh{margin-top:20px}.chlist{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:10px}
.chbtn{display:flex;gap:12px;align-items:center;width:100%;text-align:left;padding:8px;border:1px solid var(--line);border-radius:12px;background:var(--card);color:var(--ink);font:inherit;cursor:pointer;min-height:64px}
.chbtn img{width:96px;height:54px;object-fit:cover;border-radius:8px;flex:none;background:var(--line)}
.chtxt{display:flex;flex-direction:column;min-width:0}.chn{font-weight:600}.cht{color:var(--mute);font-size:.85rem}
.ch[aria-current=true] .chbtn,.ch.on .chbtn{border-color:var(--brand);box-shadow:0 0 0 2px var(--brand)}
.doc{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:18px;margin:20px 0}.sub{color:var(--mute);margin:0 0 12px}
.tr{margin:0;padding:0;list-style:none;display:grid;gap:12px}.tr p{margin:0}
.dl{margin:0;padding-left:1.1em}.dl li{margin:6px 0}.note ul{margin:0;padding-left:1.1em}.note li{margin:4px 0}
.end{text-align:center;padding:24px 0}.small{color:var(--mute)}
footer{max-width:1040px;margin:0 auto;padding:16px;color:var(--mute);text-align:center;font-size:.9rem}
@media (max-width:640px){.chlist{grid-template-columns:1fr}.btn{width:100%}}
@media (prefers-reduced-motion:no-preference){.chbtn{transition:border-color .15s,box-shadow .15s}}