:root { --bg:#f4f6f8; --card:#fff; --fg:#1b2733; --muted:#6b7a8a; --line:#e1e6eb; --primary:#ff9900; --ok:#1d8a4a; --warn:#b26a00; --err:#c0392b; }
* { box-sizing:border-box; }
body { margin:0; font-family:"微软雅黑","Microsoft YaHei",-apple-system,"PingFang SC",sans-serif; background:var(--bg); color:var(--fg); }
header { display:flex; justify-content:space-between; align-items:center; padding:12px 24px; background:#232f3e; color:#fff; }
.brand { font-weight:600; font-size:17px; }
main { max-width:1100px; margin:24px auto; padding:0 16px; }
.card { background:var(--card); border:1px solid var(--line); border-radius:8px; padding:20px; margin-bottom:16px; }
.card.narrow { max-width:380px; margin:60px auto; }
h2 { margin:0 0 14px; font-size:18px; } h3 { margin:0 0 10px; }
label { display:block; margin:10px 0; font-size:14px; }
input:not([type=radio]):not([type=file]), textarea, select { width:100%; padding:8px 10px; border:1px solid var(--line); border-radius:6px; font:inherit; margin-top:4px; }
.row { display:flex; gap:10px; align-items:center; flex-wrap:wrap; } .row.right { justify-content:flex-end; }
.row input:not([type=file]) { flex:1; margin-top:0; }
button { padding:8px 14px; border:1px solid var(--line); border-radius:6px; background:#fff; cursor:pointer; font:inherit; }
button.primary { background:var(--primary); border-color:var(--primary); color:#111; font-weight:600; }
button.link { border:none; background:none; color:#0073bb; padding:0; }
button.small { padding:4px 10px; font-size:13px; }
button:disabled { opacity:.5; cursor:default; }
.hint { color:var(--muted); font-size:13px; } .error { color:var(--err); font-size:13px; min-height:1em; }
.hidden { display:none !important; }
table { width:100%; border-collapse:collapse; font-size:14px; }
th, td { text-align:left; padding:8px 6px; border-bottom:1px solid var(--line); }
.badge { display:inline-block; padding:2px 10px; border-radius:12px; font-size:12px; background:#eef1f4; color:var(--muted); }
.badge.ready { background:#e6f4ea; color:var(--ok); } .badge.processing, .badge.uploading { background:#fff4e0; color:var(--warn); } .badge.failed { background:#fde8e6; color:var(--err); }
.review-head { display:flex; gap:12px; align-items:center; }
.kp { background:var(--card); border:1px solid var(--line); border-radius:8px; margin-bottom:14px; }
.kp-head { display:flex; gap:12px; align-items:center; padding:14px 18px; border-bottom:1px solid var(--line); flex-wrap:wrap; }
.kp-head .name { font-weight:600; font-size:16px; } .kp-head .pages { color:var(--muted); font-size:13px; }
.kp-head .warn { color:var(--warn); font-size:13px; }
.kp-summary { padding:10px 18px; color:var(--muted); font-size:13px; }
.thumbs { display:flex; gap:6px; padding:0 18px 10px; overflow-x:auto; }
.thumbs img { height:70px; border:1px solid var(--line); border-radius:4px; cursor:zoom-in; }
.q { padding:14px 18px; border-top:1px dashed var(--line); }
.q.approved { border-left:4px solid var(--ok); } .q.pending { border-left:4px solid var(--warn); } .q.regenerating { opacity:.6; }
.q-top { display:flex; justify-content:space-between; gap:10px; align-items:flex-start; }
.q-stem { font-weight:500; } .q-meta { color:var(--muted); font-size:12px; white-space:nowrap; }
.q-opts { margin:8px 0 0; padding:0; list-style:none; font-size:14px; }
.q-opts li { padding:2px 0; } .q-opts li.correct { color:var(--ok); font-weight:600; }
.q-exp { color:var(--muted); font-size:13px; margin-top:6px; }
.q-actions { margin-top:8px; display:flex; gap:6px; flex-wrap:wrap; }
.add-row { padding:10px 18px; }
dialog { border:none; border-radius:10px; padding:22px; width:min(640px, 92vw); }
dialog::backdrop { background:rgba(0,0,0,.35); }
.opts label { display:flex; gap:8px; align-items:center; } .opts label input[type=text], .opts label input:not([type=radio]) { flex:1; margin-top:0; }

/* ---------- 一期 B：导航 / 上课 / 学员端 ---------- */
nav { display:flex; gap:18px; } nav .link { color:#fff; opacity:.85; } nav .link:hover { opacity:1; }
.mono { font-family: ui-monospace, Menlo, Consolas, monospace; }
.code-chip { background:#fff4e0; color:#8a5a00; border-radius:14px; padding:3px 12px; font-size:13px; } .code-chip b { font-size:16px; letter-spacing:2px; }
.tabs { display:flex; gap:6px; margin-top:14px; border-bottom:1px solid var(--line); }
.tab { border:none; background:none; padding:8px 14px; border-bottom:2px solid transparent; color:var(--muted); }
.tab.active { color:var(--fg); border-bottom-color:var(--primary); font-weight:600; }
#live-steps button { min-width:120px; }
.step { border:1px solid var(--line); border-radius:8px; margin-bottom:8px; padding:0 14px; }
.step.active { border-color:var(--primary); box-shadow:0 0 0 2px #ffe3b3; }
.step summary { display:flex; gap:14px; align-items:center; padding:10px 0; cursor:pointer; list-style:none; }
.step summary .name { flex:1; font-weight:600; } .step summary .stat { color:var(--muted); font-size:13px; }
.rate { font-size:13px; min-width:90px; text-align:right; } .rate.good { color:var(--ok); } .rate.mid { color:var(--warn); } .rate.bad { color:var(--err); }
.bar { width:120px; height:8px; background:#eef1f4; border-radius:4px; overflow:hidden; } .bar i { display:block; height:100%; background:var(--ok); }
.q-line { padding:8px 0 10px; border-top:1px dashed var(--line); font-size:14px; }
.ok { color:var(--ok); font-weight:700; } .ko { color:var(--err); font-weight:700; } .na { color:#b0b8c0; }
#live-students td, #live-students th { text-align:center; } #live-students td:first-child, #live-students th:first-child { text-align:left; }

body.student main { max-width:720px; }
.big-input { font-size:28px !important; letter-spacing:6px; text-align:center; }
.center { text-align:center; }
.waiting p { color:var(--muted); margin-top:14px; }
.spinner { width:34px; height:34px; border:4px solid #eef1f4; border-top-color:var(--primary); border-radius:50%; margin:10px auto 0; animation:spin 1s linear infinite; }
@keyframes spin { to { transform:rotate(360deg); } }
@media (prefers-reduced-motion: reduce) { .spinner { animation:none; } }
.quiz .q-head { display:flex; justify-content:space-between; color:var(--muted); font-size:13px; margin-bottom:8px; }
.quiz .stem { font-size:18px; font-weight:600; line-height:1.5; margin-bottom:14px; }
.timer { font-weight:700; color:var(--fg); } .timer.urgent { color:var(--err); }
.choices.btns { display:grid; gap:10px; }
.choices.btns button { text-align:left; padding:14px 16px; font-size:16px; border-radius:10px; border:1px solid var(--line); background:#fff; }
.choices.btns button:hover:not(:disabled) { border-color:var(--primary); background:#fff8ec; }
.choices.btns button b { display:inline-block; width:26px; }
ul.choices { list-style:none; padding:0; margin:0 0 12px; } ul.choices li { padding:8px 12px; border:1px solid var(--line); border-radius:8px; margin-bottom:6px; }
ul.choices li.correct { border-color:var(--ok); background:#e6f4ea; } ul.choices li.mine:not(.correct) { border-color:var(--err); background:#fde8e6; }
.quiz.right .result { color:var(--ok); font-weight:700; } .quiz.wrong .result { color:var(--err); font-weight:700; }
.explain { background:#f4f6f8; border-radius:8px; padding:10px 12px; font-size:14px; line-height:1.6; }
.score { font-size:56px; font-weight:700; color:var(--primary); } .score small { font-size:22px; color:var(--muted); }
table.mine { margin:14px auto; text-align:left; } table.mine td { font-size:14px; }