/* Trang tra cứu tĩnh trong /on-thi/ (biển báo, mẹo ghi nhớ, sa hình), nạp sau kien-thuc/style.css.
   Sinh bởi scripts/build_on_thi.py. */
.muted{color:var(--muted)}
.small{font-size:.86rem}
.sec{font-size:1.3rem;font-weight:800;margin:32px 0 12px}

/* Ô tìm biển */
.finder{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin:8px 0 14px}
.finder input{flex:1 1 320px;font:inherit;padding:13px 16px;border:1.5px solid var(--line);border-radius:12px;background:#fff;color:var(--ink)}
.finder input:focus{outline:3px solid var(--accent);outline-offset:1px;border-color:var(--brand)}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 8px}
.chips a{font-size:.88rem;font-weight:600;padding:7px 14px;border-radius:999px;border:1.5px solid var(--line);background:#fff;color:var(--brand);text-decoration:none}
.chips a:hover{border-color:var(--brand)}

/* Lưới biển */
.sign-group{margin:28px 0}
.sign-group h2{font-size:1.35rem;font-weight:800;margin:0 0 4px}
.sign-group h2 a{color:var(--ink);text-decoration:none}
.sign-group h2 a:hover{color:var(--brand)}
.sign-group h2 small{font-size:.85rem;font-weight:600;color:var(--muted)}
.sign-group>p{margin:0 0 12px}
.signs{display:grid;gap:10px;grid-template-columns:repeat(auto-fill,minmax(140px,1fr))}
.sign{display:flex;flex-direction:column;align-items:center;gap:4px;text-align:center;padding:12px 8px;background:#fff;border:1px solid var(--line);border-radius:14px;text-decoration:none;color:var(--ink);transition:border-color .15s,transform .15s}
.sign:hover{border-color:var(--brand);transform:translateY(-2px)}
.sign img{width:84px;height:84px;object-fit:contain}
.sign b{font-size:.82rem;color:var(--brand)}
.sign span{font-size:.82rem;line-height:1.35}
.sign[hidden],.sign-group[hidden]{display:none}

/* Trang một biển */
.sign-hero{display:flex;flex-wrap:wrap;gap:20px;align-items:center;padding:20px 0 4px}
.sign-hero img{width:200px;height:200px;object-fit:contain;background:var(--bg-soft);border:1px solid var(--line);border-radius:18px;padding:14px}
.sign-hero>div{flex:1 1 260px}
.sign-hero h1{font-size:clamp(1.5rem,4.4vw,2.1rem);font-weight:800;margin:10px 0 6px}
.sign-hero p{margin:0}
.pn{display:flex;justify-content:space-between;gap:10px;margin:28px 0 0}
.pn a{font-weight:700;text-decoration:none;padding:8px 14px;border:1.5px solid var(--line);border-radius:10px}
.pn a:hover{border-color:var(--brand)}
.q{border:1px solid var(--line);border-radius:14px;padding:14px 16px;margin:0 0 12px}
.q p{margin:0 0 8px}
.q img{max-height:220px;width:auto;margin:0 auto 10px}
.ans{list-style:none;padding:0;margin:0}
.ans li{padding:6px 10px;border-radius:8px}
.ans li.ok{background:#e8f7ee;color:#15803d;font-weight:700}

/* Mẹo ghi nhớ */
.meo{margin:8px 0 28px;scroll-margin-top:80px}
.tip{border:1px solid var(--line);border-left:4px solid var(--accent);border-radius:0 12px 12px 0;padding:12px 16px;margin:0 0 12px;background:#fff}
.tip h3{font-size:1.05rem;margin:0 0 4px}
.tip p{margin:0}

/* Sa hình */
.bai{border:1px solid var(--line);border-radius:16px;padding:18px 20px;margin:0 0 16px;scroll-margin-top:80px}
.bai h2{display:flex;gap:10px;align-items:center;font-size:1.25rem;margin:0 0 8px}
.bai .no{flex:none;width:34px;height:34px;border-radius:10px;background:var(--brand);color:#fff;display:grid;place-items:center;font-size:1rem}
.bai h3{font-size:1rem;margin:14px 0 6px}
.err li::marker{content:"✗  ";color:#c62828}
.cta-btns .btn-ghost{color:#fff}