:root{color-scheme:light dark;font:17px/1.7 system-ui,sans-serif;background:#10141e;color:#e6e9f1}body{max-width:760px;margin:auto;padding:36px 24px 72px}nav{display:flex;gap:24px;border-bottom:1px solid #3a4152;padding-bottom:20px;margin-bottom:42px}a{color:#91dcff}h1{font-size:2.5rem;line-height:1.15;margin:12px 0 24px}h2{font-size:1.35rem;margin-top:32px}p,li{max-width:70ch}.muted{color:#aeb7ca}.brand{color:#fff;text-decoration:none;font-weight:700}section[lang=ja]{border-top:1px solid #3a4152;margin-top:56px;padding-top:24px}footer{border-top:1px solid #3a4152;margin-top:56px;padding-top:24px;font-size:.85rem}