:root{--bg:#ffffff;--fg:#14181f;--muted:#5b6472;--line:#e3e7ed;--accent:#1f6f4a}@media (prefers-color-scheme:dark){:root{--bg:#10141a;--fg:#e8ecf2;--muted:#9aa4b2;--line:#262d38;--accent:#5fbf8d}}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--fg);font-family:system-ui,-apple-system,Hiragino Kaku Gothic ProN,Noto Sans JP,Yu Gothic,sans-serif;line-height:1.7}a{color:inherit}.wrap{max-width:880px;margin:0 auto;padding:32px 20px 64px}.site-header{border-bottom:1px solid var(--line)}.site-header .wrap{padding-block:20px}.site-title{font-size:20px;font-weight:700;text-decoration:none}.lede{color:var(--muted);margin-top:4px}.course{border:1px solid var(--line);border-radius:10px;padding:20px;margin-top:24px}.course h2{margin:0;font-size:18px}.course .tagline{color:var(--muted);margin:6px 0 16px}.sections{list-style:none;margin:0;padding:0;display:grid;grid-gap:10px;gap:10px}.sections a{display:block;border:1px solid var(--line);border-radius:8px;padding:12px 14px;text-decoration:none}.sections a:hover{border-color:var(--accent)}.sections .name{font-weight:600}.breadcrumb,.sections .purpose{color:var(--muted);font-size:14px}.pending{border:1px dashed var(--line);border-radius:10px;padding:24px;margin-top:20px}.pending strong{font-size:18px}.drill{margin-top:20px}.drill-bar{display:flex;flex-wrap:wrap;align-items:center;gap:8px 16px;font-size:14px;color:var(--muted);padding-bottom:12px;border-bottom:1px solid var(--line)}.drill-bank select{font:inherit;padding:4px 6px;border:1px solid var(--line);border-radius:6px;background:var(--bg);color:var(--fg)}.drill-stats{margin-left:auto}.drill-card{border:1px solid var(--line);border-radius:10px;padding:20px;margin-top:16px}.drill-question{margin:0;white-space:pre-wrap}.drill-figure{margin-top:16px;border-left:4px solid var(--accent);background:color-mix(in srgb,var(--accent) 8%,transparent);border-radius:0 8px 8px 0;padding:12px 14px}.drill-figure strong{display:block;font-size:13px;letter-spacing:.04em;color:var(--accent)}.drill-figure p{margin:4px 0 0;white-space:pre-wrap}.drill-choices{list-style:none;margin:20px 0 0;padding:0;display:grid;grid-gap:8px;gap:8px}.drill-choice{display:flex;gap:10px;width:100%;text-align:left;font:inherit;color:inherit;background:var(--bg);border:1px solid var(--line);border-radius:8px;padding:12px 14px;cursor:pointer}.drill-choice:hover:not(:disabled){border-color:var(--accent)}.drill-choice:disabled{cursor:default;opacity:1}.drill-choice .drill-label{font-weight:700;flex:none}.drill-choice.is-answer{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 12%,transparent)}.drill-choice.is-wrong{border-color:#c0392b;background:color-mix(in srgb,#c0392b 12%,transparent)}.drill-result{margin-top:20px;padding-top:16px;border-top:1px solid var(--line)}.drill-verdict{margin:0;font-weight:700}.drill-verdict.is-ok{color:var(--accent)}.drill-verdict.is-ng{color:#c0392b}.drill-explanation{margin-top:12px}.drill-explanation strong{font-size:13px;letter-spacing:.04em;color:var(--muted)}.drill-explanation p{margin:4px 0 0}.drill-muted,.drill-src{color:var(--muted)}.drill-src{margin:12px 0 0;font-size:13px}.drill-nav{display:flex;gap:10px;margin-top:16px}.drill-nav button{font:inherit;color:inherit;background:var(--bg);border:1px solid var(--line);border-radius:8px;padding:8px 16px;cursor:pointer}.drill-nav button:disabled{color:var(--muted);cursor:default}.drill-notice{border:1px solid var(--line);border-radius:10px;padding:16px;margin-top:16px}.drill-error{border-color:#c0392b;color:#c0392b}