:root{--bg:#f5f7fb;--card:#fff;--text:#1f2937;--muted:#6b7280;--primary:#2f6fed;--line:#e5e7eb;--danger:#dc2626;--ok:#15803d;--warn:#fff7e0}
@media (prefers-color-scheme:dark){:root{--bg:#111827;--card:#1f2937;--text:#f3f4f6;--muted:#9ca3af;--line:#374151;--warn:#3a321a}}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--text);font:16px/1.65 -apple-system,BlinkMacSystemFont,"PingFang TC","Noto Sans TC","Microsoft JhengHei",sans-serif;padding-bottom:env(safe-area-inset-bottom)}
a{color:var(--primary)}
.top{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:8px;padding:10px 16px;background:var(--primary);color:#fff;padding-top:max(10px,env(safe-area-inset-top))}
.top a{color:#fff;text-decoration:none}
.brand{font-weight:700;font-size:18px}
.top nav{display:flex;flex-wrap:wrap;gap:14px;align-items:center}
.who{opacity:.85;font-size:14px}
main{max-width:760px;margin:0 auto;padding:16px}
h1{font-size:22px;margin:8px 0 12px}h2{font-size:18px;margin:0 0 8px}h3{font-size:16px;margin:16px 0 8px}
.card{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:16px;margin:0 0 14px}
.card.narrow{max-width:420px;margin:24px auto}
.card.warn{background:var(--warn)}
.muted{color:var(--muted);font-size:14px}
.error{color:var(--danger)}.ok{color:var(--ok)}
label{display:block;margin:0 0 12px;font-size:14px;color:var(--muted)}
input,select,textarea{display:block;width:100%;margin-top:4px;padding:10px 12px;font:inherit;color:var(--text);background:var(--bg);border:1px solid var(--line);border-radius:8px}
.btn{display:inline-block;padding:11px 20px;font:inherit;font-weight:600;color:#fff;background:var(--primary);border:0;border-radius:10px;text-decoration:none;cursor:pointer}
.btn:disabled{opacity:.5}.btn.danger{background:var(--danger)}.btn.ghost{background:transparent;color:var(--primary);border:1px solid var(--primary)}
.btn.small{padding:6px 12px;font-size:14px}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 12px}
.chip{padding:6px 14px;border-radius:99px;border:1px solid var(--line);background:var(--card);text-decoration:none;color:var(--text);font-size:14px}
.chip.on{background:var(--primary);border-color:var(--primary);color:#fff}
.list{list-style:none;margin:0;padding:0}
.list li a{display:flex;flex-wrap:wrap;gap:8px;align-items:center;padding:12px 14px;margin-bottom:8px;background:var(--card);border:1px solid var(--line);border-radius:10px;text-decoration:none;color:var(--text)}
.tag{display:inline-block;padding:1px 10px;border-radius:99px;background:var(--primary);color:#fff;font-size:13px}
.thumbs{display:flex;flex-wrap:wrap;gap:8px;margin:8px 0}
.thumbs img{width:96px;height:96px;object-fit:cover;border-radius:8px;border:1px solid var(--line)}
dt{font-weight:700;margin-top:8px}dd{margin:0 0 4px}
ul{padding-left:20px}
.row{display:grid;grid-template-columns:1fr;gap:6px;margin-bottom:6px}
@media(min-width:640px){.row{grid-template-columns:repeat(3,1fr)}.row strong{grid-column:1/-1}}
.plain{list-style:none;padding:0}.plain li{display:flex;gap:10px;align-items:center;margin-bottom:6px}
form.inline{display:inline}
hr{border:0;border-top:1px solid var(--line);margin:12px 0}
.subjects-pick{display:flex;flex-wrap:wrap;gap:6px 14px;align-items:center;margin:4px 0 12px}
.subjects-pick .muted{flex:0 0 100%}
label.check{display:inline-flex;align-items:center;gap:6px;margin:0;color:var(--text);font-size:15px}
label.check input{display:inline-block;width:auto;margin:0}
.row .subjects-pick{grid-column:1/-1}
[hidden]{display:none!important}
.quiz-bar{display:flex;justify-content:space-between;align-items:center;margin:4px 0 10px;font-weight:600}
.timer{font-variant-numeric:tabular-nums;color:var(--primary)}.timer.low{color:var(--danger)}
.qtext{font-size:18px;margin:0 0 12px}
label.opt{display:flex;align-items:flex-start;gap:8px;margin:0 0 10px;padding:12px 14px;border:1px solid var(--line);border-radius:10px;color:var(--text);font-size:16px;cursor:pointer}
label.opt input{display:inline-block;width:auto;margin:5px 0 0}
.quiz-nav{display:flex;gap:10px;justify-content:space-between}
.card.score{text-align:center}.card.score .big{font-size:44px;font-weight:700;color:var(--primary)}
.card.result.right{border-left:5px solid var(--ok)}.card.result.wrong{border-left:5px solid var(--danger)}.card.result.pending{border-left:5px solid #d97706}
.feedback{background:var(--bg);border-radius:8px;padding:10px 12px}
.tag.gray{background:var(--muted)}
.row-actions{display:flex;gap:8px;flex-wrap:wrap;margin:8px 0 0}