:root {
  --bg: #070d16;
  --bg-soft: #0b1422;
  --panel: #0e1929;
  --panel-2: #121f33;
  --line: rgba(255, 255, 255, 0.08);
  --line-strong: rgba(255, 255, 255, 0.16);
  --text: #e9f0fa;
  --muted: #93a7c2;
  --dim: #6c7f99;
  --accent: #35e0c5;
  --accent-soft: rgba(53, 224, 197, 0.12);
  --indigo: #7c9cff;
  --indigo-soft: rgba(124, 156, 255, 0.12);
  --warn: #ffbe76;
  --danger: #ff6f6f;
  --radius: 16px;
  --shadow: 0 20px 50px rgba(0, 0, 0, 0.45);
  --font: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html, body { margin: 0; height: 100%; }
body {
  font-family: var(--font);
  color: var(--text);
  background:
    radial-gradient(1200px 600px at 12% -10%, rgba(53, 224, 197, 0.10), transparent 60%),
    radial-gradient(900px 500px at 90% 0%, rgba(124, 156, 255, 0.10), transparent 55%),
    var(--bg);
  -webkit-font-smoothing: antialiased;
}
button, input, select, textarea { font-family: inherit; color: inherit; }
button { cursor: pointer; }
svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.app { min-height: 100%; }

/* ============================ 首页 ============================ */
.landing {
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(340px, 0.85fr);
  gap: 56px;
  align-items: center;
  padding: 64px clamp(24px, 6vw, 96px);
}
.landing-hero { max-width: 660px; }
.brand-row { display: flex; align-items: center; gap: 14px; margin-bottom: 42px; }
.brand-mark {
  width: 46px; height: 46px; border-radius: 14px;
  display: grid; place-items: center;
  font-size: 24px; font-family: Georgia, "Songti SC", serif;
  color: #04141a;
  background: linear-gradient(140deg, #6ff3dd, #22b8c9);
  box-shadow: 0 10px 30px rgba(53, 224, 197, 0.30);
}
.brand-name { font-size: 17px; letter-spacing: 0.5px; font-weight: 600; }
.brand-sub { font-size: 11px; color: var(--dim); letter-spacing: 2.4px; text-transform: uppercase; margin-top: 3px; }
.landing h1 {
  font-size: clamp(30px, 3.6vw, 46px);
  line-height: 1.28; margin: 0 0 20px; font-weight: 600; letter-spacing: 0.5px;
}
.landing h1::after { content: ""; display: block; width: 88px; height: 3px; margin-top: 22px; background: linear-gradient(90deg, var(--accent), transparent); }
.hero-desc { color: var(--muted); font-size: 15.5px; line-height: 1.9; max-width: 560px; }
.hero-points { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 38px; }
.point { padding: 16px 16px 18px; border: 1px solid var(--line); border-radius: 14px; background: rgba(255, 255, 255, 0.025); }
.point span { font-size: 11px; color: var(--accent); letter-spacing: 1.6px; }
.point strong { display: block; margin: 8px 0 8px; font-size: 14px; font-weight: 600; }
.point p { margin: 0; font-size: 12.5px; color: var(--muted); line-height: 1.7; }
.hero-note { margin-top: 28px; font-size: 12px; color: var(--dim); border-left: 2px solid var(--line-strong); padding-left: 12px; line-height: 1.8; }

.landing-panel { justify-self: end; width: 100%; max-width: 420px; }
.panel-card {
  background: linear-gradient(180deg, rgba(23, 38, 58, 0.95), rgba(12, 22, 36, 0.95));
  border: 1px solid var(--line-strong);
  border-radius: 22px; padding: 22px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(20px);
}
.panel-tabs { display: flex; gap: 6px; background: rgba(0, 0, 0, 0.25); padding: 5px; border-radius: 12px; margin-bottom: 20px; }
.tab { flex: 1; border: 0; background: transparent; padding: 10px; border-radius: 9px; color: var(--muted); font-size: 13.5px; transition: 0.2s; }
.tab.active { background: var(--accent-soft); color: var(--accent); }
.pane { display: none; }
.pane.active { display: block; }
label { display: block; font-size: 12.5px; color: var(--muted); margin-bottom: 14px; }
label input, label select {
  width: 100%; margin-top: 7px; padding: 11px 13px; font-size: 14px;
  background: rgba(0, 0, 0, 0.28); border: 1px solid var(--line); border-radius: 10px; outline: none;
  transition: 0.2s;
}
label input:focus, label select:focus { border-color: rgba(53, 224, 197, 0.55); background: rgba(0, 0, 0, 0.4); }
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.btn {
  border: 1px solid var(--line); background: rgba(255, 255, 255, 0.05); color: var(--text);
  padding: 11px 18px; border-radius: 10px; font-size: 14px; transition: 0.2s;
}
.btn:hover { border-color: var(--line-strong); background: rgba(255, 255, 255, 0.09); }
.btn.primary {
  width: 100%; margin-top: 6px; border: 0; font-weight: 600; letter-spacing: 0.5px;
  color: #04141a; background: linear-gradient(135deg, #6ff3dd, #2fc8d8);
  box-shadow: 0 10px 26px rgba(53, 224, 197, 0.25);
}
.btn.primary:hover { filter: brightness(1.06); }
.btn.ghost { background: transparent; }
.hint { font-size: 11.5px; color: var(--dim); line-height: 1.7; margin: 12px 0 0; }
.demo-link {
  width: 100%; margin-top: 12px; padding: 10px; border-radius: 10px;
  border: 1px dashed var(--line-strong); background: transparent;
  color: var(--muted); font-size: 12px; transition: 0.2s;
}
.demo-link:hover { color: var(--accent); border-color: rgba(53, 224, 197, 0.4); }
.recent { margin-top: 20px; border-top: 1px solid var(--line); padding-top: 16px; }
.recent-title { font-size: 12px; color: var(--dim); margin-bottom: 10px; }
.recent-list { display: flex; flex-direction: column; gap: 8px; }
.recent-item {
  display: flex; align-items: center; justify-content: space-between; gap: 10px;
  padding: 10px 12px; border-radius: 10px; border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.03); font-size: 12.5px; color: var(--muted); cursor: pointer;
}
.recent-item:hover { border-color: var(--line-strong); color: var(--text); }
.recent-item b { color: var(--text); font-weight: 500; }
.recent-item em { font-style: normal; font-size: 11px; color: var(--accent); }
.empty { font-size: 12px; color: var(--dim); padding: 10px 2px; }

/* ============================ 教室 ============================ */
.room { height: 100vh; display: flex; flex-direction: column; overflow: hidden; }
.room-head {
  height: 66px; flex: none; display: flex; align-items: center; gap: 12px;
  padding: 0 18px; border-bottom: 1px solid var(--line); background: rgba(9, 16, 27, 0.9);
}
.room-title .line1 { display: flex; align-items: center; gap: 10px; font-size: 15px; font-weight: 600; }
.room-title .line2 { display: flex; align-items: center; gap: 7px; margin-top: 5px; font-size: 11.5px; color: var(--dim); }
.status-pill {
  font-size: 10.5px; font-weight: 400; color: var(--accent); background: var(--accent-soft);
  border: 1px solid rgba(53, 224, 197, 0.3); padding: 2px 8px; border-radius: 999px;
}
.status-pill.ended { color: var(--warn); background: rgba(255, 190, 118, 0.1); border-color: rgba(255, 190, 118, 0.3); }
.code-chip {
  border: 1px dashed var(--line-strong); background: transparent; color: var(--muted);
  font-size: 11px; padding: 3px 9px; border-radius: 7px; letter-spacing: 1px;
}
.code-chip:hover { color: var(--accent); border-color: rgba(53, 224, 197, 0.4); }
.share-hint {
  max-width: 320px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
  color: var(--dim); font-size: 11px;
}
@media (max-width: 760px) {
  .share-hint { display: none; }
}
.room-right { margin-left: auto; display: flex; align-items: center; gap: 14px; }
.ai-badge {
  display: flex; align-items: center; gap: 8px; font-size: 11.5px; color: var(--accent);
  border: 1px solid rgba(53, 224, 197, 0.22); background: rgba(53, 224, 197, 0.06);
  padding: 6px 12px; border-radius: 999px;
}
.ai-badge .pulse { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 0 0 rgba(53, 224, 197, 0.6); animation: pulse 2.2s infinite; }
.ai-badge.thinking { color: var(--warn); border-color: rgba(255, 190, 118, 0.3); background: rgba(255, 190, 118, 0.08); }
.ai-badge.thinking .pulse { background: var(--warn); }
@keyframes pulse { 0% { box-shadow: 0 0 0 0 rgba(53, 224, 197, 0.5); } 70% { box-shadow: 0 0 0 9px rgba(53, 224, 197, 0); } 100% { box-shadow: 0 0 0 0 rgba(53, 224, 197, 0); } }
.clock { font-size: 13px; color: var(--muted); font-variant-numeric: tabular-nums; letter-spacing: 1px; }
.media-badge {
  display: flex; align-items: center; gap: 7px; font-size: 11px; color: var(--muted);
  border: 1px solid var(--line); background: rgba(255, 255, 255, 0.03);
  padding: 6px 11px; border-radius: 999px; white-space: nowrap;
}
.media-badge .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--dim); }
.media-badge.local .dot { background: var(--muted); }
.media-badge.connecting { color: var(--warn); border-color: rgba(255, 190, 118, 0.3); background: rgba(255, 190, 118, 0.08); }
.media-badge.connecting .dot { background: var(--warn); animation: pulse 1.4s infinite; }
.media-badge.connected { color: var(--accent); border-color: rgba(53, 224, 197, 0.3); background: rgba(53, 224, 197, 0.08); }
.media-badge.connected .dot { background: var(--accent); }
.media-badge.failed { color: var(--danger); border-color: rgba(255, 111, 111, 0.3); background: rgba(255, 111, 111, 0.08); }
.media-badge.failed .dot { background: var(--danger); }
.rec-badge {
  display: flex; align-items: center; gap: 7px; font-size: 11px; color: var(--danger);
  border: 1px solid rgba(255, 111, 111, 0.35); background: rgba(255, 111, 111, 0.1);
  padding: 6px 11px; border-radius: 999px; white-space: nowrap;
}
.rec-badge .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--danger); animation: recBlink 1.2s infinite; }
@keyframes recBlink { 0%, 100% { opacity: 1; } 50% { opacity: 0.3; } }
.icon-btn {
  width: 38px; height: 38px; border-radius: 10px; border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.04); display: grid; place-items: center; color: var(--muted);
}
.icon-btn:hover { color: var(--text); border-color: var(--line-strong); }
.icon-btn.ghost { background: transparent; border-color: transparent; }
.icon-btn.small { width: 28px; height: 28px; }
.icon-btn.small svg { width: 15px; height: 15px; }

.room-main { flex: 1; min-height: 0; display: grid; grid-template-columns: minmax(0, 1fr) 370px; gap: 14px; padding: 14px 18px; }

.stage {
  position: relative; min-height: 0; border-radius: 20px; overflow: hidden;
  border: 1px solid var(--line); background:
    radial-gradient(900px 480px at 80% 0%, rgba(124, 156, 255, 0.10), transparent 60%),
    linear-gradient(160deg, #0d1a2b, #070e18 70%);
  box-shadow: inset 0 0 120px rgba(0, 0, 0, 0.5);
}
.stage-video { width: 100%; height: 100%; object-fit: cover; background: #05090f; }
.stage-share { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: contain; background: #05090f; }
.stage-board { position: absolute; inset: 0; display: flex; flex-direction: column; padding: clamp(20px, 4vw, 46px); }
.board-kicker { font-size: 11px; letter-spacing: 2px; color: var(--dim); text-transform: uppercase; }
.stage-board h2 { margin: 14px 0 10px; font-size: clamp(24px, 2.8vw, 38px); font-weight: 600; letter-spacing: 0.5px; }
.board-sub { margin: 0; color: var(--muted); font-size: 13px; line-height: 1.8; }
.board-body { margin-top: auto; display: grid; grid-template-columns: 1.1fr 1fr; gap: 26px; align-items: end; }
.board-quote { border-left: 3px solid var(--accent); padding-left: 16px; }
.board-quote span { font-size: 11px; color: var(--accent); letter-spacing: 1.4px; }
.board-quote p { margin: 9px 0 0; font-size: clamp(14px, 1.35vw, 17px); line-height: 1.9; color: #cfe0f2; font-family: "Songti SC", "SimSun", Georgia, serif; }
.board-list { display: flex; flex-direction: column; gap: 9px; }
.board-list div {
  display: flex; align-items: center; gap: 12px; font-size: 13px; color: var(--muted);
  padding: 10px 14px; border: 1px solid var(--line); border-radius: 11px; background: rgba(255, 255, 255, 0.025);
}
.board-list b { color: var(--accent); font-weight: 500; font-size: 11px; letter-spacing: 1px; }
.board-foot { margin-top: 26px; font-size: 11.5px; color: var(--dim); border-top: 1px solid var(--line); padding-top: 14px; }

.stage-note {
  position: absolute; inset: 20px; z-index: 5; border-radius: 16px; overflow: hidden;
  background: #0b1522; border: 1px solid var(--line-strong); box-shadow: var(--shadow);
  display: flex; flex-direction: column;
}
.note-head { display: flex; align-items: center; justify-content: space-between; padding: 12px 16px; border-bottom: 1px solid var(--line); font-size: 12px; color: var(--muted); letter-spacing: 1px; }
.note-body { padding: 22px 26px; overflow: auto; font-family: "Songti SC", "SimSun", Georgia, serif; font-size: 15px; line-height: 2.1; color: #dbe7f5; }
.note-body h4 { margin: 22px 0 10px; font-size: 15px; color: var(--accent); font-family: var(--font); letter-spacing: 0.5px; }
.note-body h4:first-child { margin-top: 0; }
.note-body p { margin: 0 0 12px; text-indent: 2em; }
.note-body .quote { color: var(--warn); }

.stage-overlay { position: absolute; inset: 0; pointer-events: none; display: flex; align-items: flex-end; padding: 18px; }
.speaking-flag {
  margin-left: auto; display: flex; align-items: center; gap: 8px;
  background: rgba(6, 14, 24, 0.85); border: 1px solid rgba(53, 224, 197, 0.35);
  color: var(--accent); font-size: 12px; padding: 7px 13px; border-radius: 999px;
}
.speaking-flag span { width: 6px; height: 6px; border-radius: 50%; background: var(--accent); animation: pulse 1.4s infinite; }
.stage-tabs {
  position: absolute; top: 16px; right: 16px; display: flex; gap: 4px;
  background: rgba(6, 12, 20, 0.7); border: 1px solid var(--line); border-radius: 10px; padding: 4px;
}
.stage-tab { border: 0; background: transparent; color: var(--dim); font-size: 11.5px; padding: 6px 12px; border-radius: 7px; }
.stage-tab.active { color: var(--accent); background: var(--accent-soft); }

/* 侧栏 */
.side { min-height: 0; display: flex; flex-direction: column; border-radius: 20px; border: 1px solid var(--line); background: rgba(13, 23, 38, 0.75); overflow: hidden; }
.side-tabs { display: flex; gap: 4px; padding: 10px; border-bottom: 1px solid var(--line); }
.side-tab { flex: 1; border: 0; background: transparent; color: var(--muted); font-size: 12.5px; padding: 9px 6px; border-radius: 9px; }
.side-tab em { font-style: normal; font-size: 10px; color: var(--dim); margin-left: 2px; }
.side-tab.active { color: var(--accent); background: var(--accent-soft); }
.side-pane { display: none; flex: 1; min-height: 0; flex-direction: column; }
.side-pane.active { display: flex; }

.ai-card { display: flex; gap: 12px; align-items: center; padding: 14px; border-bottom: 1px solid var(--line); background: linear-gradient(120deg, rgba(53, 224, 197, 0.07), transparent); }
.ai-avatar {
  width: 42px; height: 42px; border-radius: 12px; flex: none; display: grid; place-items: center;
  font-family: Georgia, "Songti SC", serif; font-size: 19px; color: #04141a;
  background: linear-gradient(140deg, #7ef5e2, #25b9c9);
  box-shadow: 0 0 0 4px rgba(53, 224, 197, 0.10);
}
.ai-info { min-width: 0; flex: 1; }
.ai-name { font-size: 13.5px; font-weight: 600; display: flex; align-items: center; gap: 8px; }
.ai-state { font-size: 11.5px; color: var(--muted); margin-top: 4px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.badge { font-size: 9.5px; font-weight: 400; padding: 2px 6px; border-radius: 5px; letter-spacing: 0.5px; }
.badge.ai { color: var(--accent); background: var(--accent-soft); border: 1px solid rgba(53, 224, 197, 0.3); }
.badge.teacher { color: var(--indigo); background: var(--indigo-soft); border: 1px solid rgba(124, 156, 255, 0.3); }
.badge.student { color: var(--muted); background: rgba(255, 255, 255, 0.05); border: 1px solid var(--line); }

.member-list { flex: 1; overflow: auto; padding: 8px; display: grid; grid-template-columns: 1fr 1fr; gap: 8px; align-content: start; }
.member {
  position: relative; border-radius: 12px; border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.03); padding: 9px 10px 10px; min-height: 92px;
  display: flex; flex-direction: column; gap: 8px; transition: 0.2s;
}
.member.online { border-color: rgba(53, 224, 197, 0.22); }
.member.speaking { box-shadow: 0 0 0 2px rgba(53, 224, 197, 0.35), 0 0 22px rgba(53, 224, 197, 0.12); }
.member .ava {
  width: 34px; height: 34px; border-radius: 10px; display: grid; place-items: center;
  font-size: 13px; font-weight: 600; color: #eaf2ff;
  background: linear-gradient(140deg, #334a6c, #22314a);
}
.member .meta { min-width: 0; }
.member .nm { font-size: 12px; display: flex; align-items: center; gap: 5px; overflow: hidden; }
.member .nm span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.member .st { font-size: 10.5px; color: var(--dim); margin-top: 4px; display: flex; align-items: center; gap: 5px; }
.member .st i { width: 5px; height: 5px; border-radius: 50%; background: var(--dim); }
.member.online .st i { background: var(--accent); }
.member .mic { position: absolute; right: 9px; bottom: 9px; font-size: 10px; color: var(--dim); }
.member .hand { position: absolute; right: 9px; top: 8px; font-size: 12px; }

/* 互动内容统一滚动区：问答 → 回答卡片 → 操作按钮 → 语音条 → 消息，自上而下一条文档流 */
.chat-scroll {
  flex: 1 1 auto; min-height: 0;
  overflow-y: auto; overflow-x: hidden;
  display: flex; flex-direction: column; gap: 10px;
  padding: 10px 12px 12px;
}
.chat-list { flex: none; min-height: 140px; overflow: visible; padding: 0; display: flex; flex-direction: column; gap: 12px; }

/* 语音对话（教师端） */
.voice-panel {
  margin: 0; padding: 10px; border: 1px solid var(--line); border-radius: 12px;
  background: linear-gradient(120deg, rgba(53, 224, 197, 0.07), rgba(124, 156, 255, 0.04));
  transition: 0.2s;
}
.voice-panel.off { opacity: 0.72; border-color: rgba(255, 190, 118, 0.25); }
.voice-main { display: flex; align-items: center; gap: 10px; }
.voice-btn {
  display: flex; align-items: center; gap: 7px; flex: none;
  border: 1px solid rgba(53, 224, 197, 0.35); background: rgba(53, 224, 197, 0.10);
  color: var(--accent); border-radius: 10px; padding: 9px 12px; font-size: 12.5px;
}
.voice-btn svg { width: 17px; height: 17px; }
.voice-btn:hover { background: rgba(53, 224, 197, 0.16); }
.voice-btn:disabled { cursor: not-allowed; opacity: 0.45; }
.voice-btn.recording {
  color: #fff; border-color: rgba(255, 111, 111, 0.55);
  background: linear-gradient(135deg, #ff7b7b, #e94e6a);
  box-shadow: 0 0 0 4px rgba(255, 111, 111, 0.12);
}
.voice-info { flex: 1; min-width: 0; }
.voice-status { font-size: 12px; color: var(--muted); line-height: 1.5; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.voice-status.ok { color: var(--accent); }
.voice-status.busy { color: var(--warn); }
.voice-status.err { color: var(--danger); }
.voice-meta { display: flex; gap: 8px; align-items: center; margin-top: 3px; font-size: 10.5px; color: var(--dim); font-variant-numeric: tabular-nums; }
.voice-meta span:last-child { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.voice-stop {
  flex: none; border: 1px solid rgba(255, 111, 111, 0.35); background: rgba(255, 111, 111, 0.12);
  color: #ffd7d7; border-radius: 9px; padding: 8px 10px; font-size: 11.5px;
}
.voice-stop:hover { background: rgba(255, 111, 111, 0.22); }
.voice-wave { display: block; width: 100%; height: 40px; margin-top: 8px; border-radius: 8px; background: rgba(0, 0, 0, 0.25); }

.msg { display: flex; gap: 9px; max-width: 92%; }
.msg .ava { width: 28px; height: 28px; border-radius: 8px; flex: none; display: grid; place-items: center; font-size: 11px; background: linear-gradient(140deg, #374f72, #253650); }
.msg .bubble { background: rgba(255, 255, 255, 0.05); border: 1px solid var(--line); border-radius: 4px 12px 12px 12px; padding: 9px 12px; font-size: 12.5px; line-height: 1.75; }
.msg .who { font-size: 10.5px; color: var(--dim); margin-bottom: 4px; }
.msg.mine { align-self: flex-end; flex-direction: row-reverse; }
.msg.mine .bubble { background: var(--accent-soft); border-color: rgba(53, 224, 197, 0.25); border-radius: 12px 4px 12px 12px; }
.msg.ai .ava { background: linear-gradient(140deg, #7ef5e2, #25b9c9); color: #04141a; font-family: Georgia, serif; }
.msg.ai .bubble { background: rgba(53, 224, 197, 0.07); border-color: rgba(53, 224, 197, 0.22); }
.msg.system { align-self: center; max-width: 100%; }
.msg.system .bubble { background: transparent; border: 0; color: var(--dim); font-size: 11px; text-align: center; padding: 2px 8px; }
.msg.system .ava, .msg.system .who { display: none; }
.typing { font-size: 11.5px; color: var(--accent); padding: 0 16px 8px; }

.chat-form { flex: none; display: flex; gap: 8px; padding: 10px 12px 6px; border-top: 1px solid var(--line); background: rgba(9, 16, 27, 0.96); box-shadow: 0 -10px 18px rgba(0, 0, 0, 0.18); }
.chat-form input { flex: 1; min-width: 0; background: rgba(0, 0, 0, 0.3); border: 1px solid var(--line); border-radius: 10px; padding: 10px 12px; font-size: 12.5px; outline: none; }
.chat-form input:focus { border-color: rgba(53, 224, 197, 0.45); }
.btn.send { border: 0; background: var(--accent-soft); color: var(--accent); font-size: 12px; padding: 0 16px; border-radius: 10px; }
.btn.attach { border: 1px solid var(--line); background: rgba(255, 255, 255, 0.04); color: var(--muted); font-size: 12px; padding: 0 12px; border-radius: 10px; }
.btn.attach:hover { color: var(--accent); border-color: rgba(53, 224, 197, 0.35); }

/* ---------- 作业附件 ---------- */
.upload-status {
  flex: none; display: flex; align-items: center; gap: 8px;
  padding: 0 14px 10px; font-size: 11px; color: var(--muted);
  background: rgba(9, 16, 27, 0.96);
}
.upload-bar { flex: 1; height: 4px; border-radius: 999px; background: rgba(255, 255, 255, 0.08); overflow: hidden; }
.upload-bar i { display: block; height: 100%; width: 0%; background: var(--accent); transition: width 0.15s; }
.link-btn { border: 0; background: transparent; color: var(--dim); font-size: 11px; text-decoration: underline; padding: 0; }

.msg .bubble.file { padding: 10px; min-width: 190px; }
.file-card { display: flex; flex-direction: column; gap: 8px; }
.file-thumb {
  display: block; max-width: 220px; max-height: 160px; border-radius: 8px;
  border: 1px solid var(--line); cursor: zoom-in; object-fit: cover;
}
.file-row { display: flex; align-items: center; gap: 9px; }
.file-icon {
  width: 34px; height: 34px; flex: none; display: grid; place-items: center;
  border-radius: 9px; font-size: 10px; letter-spacing: 0.5px; font-weight: 600;
  background: rgba(53, 224, 197, 0.10); color: var(--accent); border: 1px solid rgba(53, 224, 197, 0.22);
}
.file-icon.pdf { background: rgba(255, 111, 111, 0.12); color: #ffb3b3; border-color: rgba(255, 111, 111, 0.28); }
.file-icon.doc { background: rgba(124, 156, 255, 0.12); color: #b8caff; border-color: rgba(124, 156, 255, 0.28); }
.file-meta { min-width: 0; flex: 1; }
.file-name { font-size: 12px; color: var(--text); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; max-width: 190px; }
.file-sub { font-size: 10.5px; color: var(--dim); margin-top: 2px; }
.file-actions { display: flex; gap: 8px; }
.file-actions a, .file-actions button {
  font-size: 11px; color: var(--accent); text-decoration: none;
  border: 1px solid rgba(53, 224, 197, 0.25); border-radius: 8px; padding: 4px 9px; background: transparent;
}
.file-actions a:hover, .file-actions button:hover { background: rgba(53, 224, 197, 0.1); }

/* ---------- 放大查看 ---------- */
.lightbox {
  position: fixed; inset: 0; z-index: 60; display: flex; flex-direction: column;
  background: rgba(3, 7, 12, 0.94); backdrop-filter: blur(6px); padding: 18px;
}
.lightbox-bar { display: flex; align-items: center; justify-content: space-between; color: var(--muted); font-size: 12.5px; }
.lightbox img { flex: 1; min-height: 0; width: 100%; object-fit: contain; margin: 10px 0; }
.lightbox-tip { text-align: center; color: var(--dim); font-size: 11px; }

/* ---------- 课堂记录 ---------- */
.record-note { font-size: 11.5px; color: var(--dim); line-height: 1.8; margin: 0 0 10px; }
.record-badge { display: inline-block; font-size: 10.5px; color: var(--accent); border: 1px solid rgba(53, 224, 197, 0.3); border-radius: 999px; padding: 2px 8px; margin-left: 6px; }
.modal-foot { flex-wrap: wrap; }
.chat-tools { flex: none; display: flex; gap: 6px; padding: 4px 12px 12px; flex-wrap: wrap; background: rgba(9, 16, 27, 0.96); }
.chip { font-size: 11px; color: var(--muted); border: 1px solid var(--line); background: transparent; padding: 5px 10px; border-radius: 999px; }
.chip:hover { color: var(--accent); border-color: rgba(53, 224, 197, 0.35); }

.empty-block { margin: auto; padding: 30px; text-align: center; color: var(--dim); }
.empty-icon { font-size: 26px; color: var(--accent); opacity: 0.6; }
.empty-block p { color: var(--muted); font-size: 13px; margin: 12px 0 6px; }
.empty-block span { font-size: 11.5px; line-height: 1.8; display: block; max-width: 260px; }

.work-card { padding: 16px; overflow: auto; }
.work-head { display: flex; align-items: center; justify-content: space-between; font-size: 11px; }
.work-type { color: var(--indigo); background: var(--indigo-soft); padding: 2px 8px; border-radius: 6px; }
.work-status { color: var(--accent); }
.work-status.closed { color: var(--dim); }
.work-q { margin: 12px 0 16px; font-size: 14px; line-height: 1.8; }
.work-stats { display: flex; flex-direction: column; gap: 10px; }
.stat-row { font-size: 12px; }
.stat-top { display: flex; justify-content: space-between; color: var(--muted); margin-bottom: 5px; }
.stat-bar { height: 6px; border-radius: 999px; background: rgba(255, 255, 255, 0.06); overflow: hidden; }
.stat-bar i { display: block; height: 100%; width: 0; border-radius: 999px; background: linear-gradient(90deg, #35e0c5, #7c9cff); transition: width 0.4s; }
.work-answers { margin-top: 16px; display: flex; flex-direction: column; gap: 10px; }
.answer-card { border: 1px solid var(--line); border-radius: 10px; padding: 10px 12px; background: rgba(255, 255, 255, 0.03); }
.answer-card .ah { display: flex; justify-content: space-between; font-size: 11px; color: var(--dim); margin-bottom: 6px; }
.answer-card .av { font-size: 12.5px; line-height: 1.7; color: var(--muted); }
.answer-card .grade { margin-top: 8px; padding-top: 8px; border-top: 1px dashed var(--line); font-size: 11.5px; color: var(--accent); display: flex; justify-content: space-between; }
.answer-card .grade b { color: var(--warn); font-size: 13px; }
.work-actions { display: flex; gap: 8px; margin-top: 16px; }

/* 底栏 */
.control-bar {
  flex: none; display: flex; align-items: center; gap: 18px;
  padding: 10px 18px; border-top: 1px solid var(--line);
  background: rgba(8, 15, 26, 0.95);
}
.ctrl-group { display: flex; align-items: center; gap: 4px; }
.ctrl-group.teaching { flex: 1; justify-content: center; gap: 8px; }
.ctrl {
  min-width: 62px; border: 0; background: transparent; color: var(--muted);
  display: flex; flex-direction: column; align-items: center; gap: 4px; font-size: 10.5px;
  padding: 7px 8px; border-radius: 10px; transition: 0.2s;
}
.ctrl:hover { color: var(--text); background: rgba(255, 255, 255, 0.05); }
.ctrl.active { color: var(--accent); background: var(--accent-soft); }
.ctrl.off { color: var(--dim); }
.ctrl.off svg { opacity: 0.5; }
.ctrl.danger { color: #ffd7d7; background: rgba(255, 111, 111, 0.12); border: 1px solid rgba(255, 111, 111, 0.25); min-width: 96px; flex-direction: row; justify-content: center; font-size: 12px; padding: 10px 16px; }
.ctrl.danger:hover { background: rgba(255, 111, 111, 0.2); }
.ctrl.rec.active { color: #ffd7d7; background: rgba(255, 111, 111, 0.14); }
.ctrl.rec.active svg circle { fill: var(--danger); stroke: var(--danger); }
.tool {
  border: 1px solid var(--line); background: rgba(255, 255, 255, 0.03);
  border-radius: 11px; padding: 8px 14px; text-align: left; color: var(--text); transition: 0.2s;
}
.tool b { display: block; font-size: 12.5px; font-weight: 500; }
.tool span { display: block; font-size: 10px; color: var(--dim); margin-top: 3px; }
.tool:hover { border-color: rgba(53, 224, 197, 0.35); background: rgba(53, 224, 197, 0.06); }
.tool:disabled { opacity: 0.35; cursor: not-allowed; }

/* 弹层 */
.modal { position: fixed; inset: 0; z-index: 40; display: grid; place-items: center; background: rgba(3, 7, 12, 0.72); backdrop-filter: blur(8px); padding: 24px; }
.modal-card {
  width: min(560px, 100%); max-height: 86vh; display: flex; flex-direction: column;
  background: linear-gradient(180deg, #101d2f, #0a1420); border: 1px solid var(--line-strong);
  border-radius: 20px; box-shadow: var(--shadow); overflow: hidden;
}
.modal-head { display: flex; justify-content: space-between; align-items: flex-start; padding: 20px 22px 14px; border-bottom: 1px solid var(--line); }
.modal-head h3 { margin: 0; font-size: 16px; font-weight: 600; }
.modal-head p { margin: 6px 0 0; font-size: 12px; color: var(--dim); }
.modal-body { padding: 18px 22px; overflow: auto; }
.modal-foot { padding: 14px 22px 20px; border-top: 1px solid var(--line); display: flex; justify-content: flex-end; gap: 10px; }
.modal textarea, .modal input[type="text"] {
  width: 100%; background: rgba(0, 0, 0, 0.3); border: 1px solid var(--line);
  border-radius: 10px; padding: 11px 13px; font-size: 13px; outline: none; resize: vertical;
}
.modal textarea:focus, .modal input[type="text"]:focus { border-color: rgba(53, 224, 197, 0.45); }
.field { margin-bottom: 16px; }
.field > span { display: block; font-size: 12px; color: var(--muted); margin-bottom: 7px; }
.seg { display: flex; gap: 6px; }
.seg button { flex: 1; border: 1px solid var(--line); background: transparent; color: var(--muted); padding: 9px; border-radius: 9px; font-size: 12.5px; }
.seg button.active { border-color: rgba(53, 224, 197, 0.4); color: var(--accent); background: var(--accent-soft); }
.quick { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 10px; }
.quick button { font-size: 11.5px; border: 1px dashed var(--line-strong); background: transparent; color: var(--muted); padding: 6px 10px; border-radius: 999px; }
.quick button:hover { color: var(--accent); border-color: rgba(53, 224, 197, 0.4); }
.opt-row { display: flex; gap: 8px; align-items: center; margin-bottom: 8px; }
.opt-row input { flex: 1; }
.modal .note { font-size: 11.5px; color: var(--dim); line-height: 1.8; margin-top: 12px; }
.grade-box { border: 1px solid rgba(53, 224, 197, 0.25); background: rgba(53, 224, 197, 0.06); border-radius: 12px; padding: 14px; margin-top: 14px; }
.grade-box .score { font-size: 22px; color: var(--warn); font-weight: 600; }
.grade-box p { margin: 8px 0 0; font-size: 12.5px; color: var(--muted); line-height: 1.8; }
.record-list { display: flex; flex-direction: column; gap: 8px; }
.record-row { display: flex; gap: 10px; font-size: 12px; color: var(--muted); border-bottom: 1px dashed var(--line); padding-bottom: 8px; }
.record-row time { color: var(--dim); font-size: 10.5px; flex: none; width: 52px; }
.record-row b { color: var(--text); font-weight: 500; }

/* 轻提示：移到页面上方，并禁用指针事件，任何情况下都不遮挡可点击控件 */
.toast {
  position: fixed; left: 50%; top: 78px; bottom: auto; transform: translateX(-50%); z-index: 60;
  pointer-events: none; max-width: min(520px, calc(100vw - 32px));
  background: rgba(10, 20, 33, 0.95); border: 1px solid rgba(53, 224, 197, 0.35); color: var(--text);
  padding: 10px 18px; border-radius: 999px; font-size: 12.5px; box-shadow: var(--shadow);
  animation: toastIn 0.25s ease;
}
@keyframes toastIn { from { opacity: 0; transform: translate(-50%, -8px); } }

::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-thumb { background: rgba(255, 255, 255, 0.12); border-radius: 8px; }
::-webkit-scrollbar-track { background: transparent; }

@media (max-width: 980px) {
  .landing { grid-template-columns: 1fr; gap: 34px; padding: 40px 22px 60px; }
  .landing-panel { justify-self: stretch; max-width: none; }
  .hero-points { grid-template-columns: 1fr; }
  .room-main { grid-template-columns: 1fr; grid-template-rows: minmax(150px, 0.9fr) minmax(270px, 1.1fr); gap: 8px; padding: 8px; overflow-y: auto; }
  .room-right .ai-badge { display: none; }
  .room-right .media-badge { display: none; }
  .control-bar { flex-wrap: wrap; gap: 8px; padding: 8px 10px; }
  .ctrl-group.teaching { order: 3; flex: 1 1 100%; justify-content: flex-start; overflow-x: auto; }
  .tool { flex: none; }
  .side { border-radius: 14px; }
  .stage { min-height: 0; }
  .board-body { grid-template-columns: 1fr; gap: 14px; }
  .board-list { display: none; }
  .member-list { grid-template-columns: 1fr 1fr 1fr; }
  .ctrl { min-width: 54px; }
}

/* ============================ 课堂问答 ============================ */
.qa-panel {
  margin: 0;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: linear-gradient(180deg, rgba(16, 30, 48, 0.96), rgba(10, 20, 34, 0.96));
}
.qa-head { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.qa-title { font-size: 12px; letter-spacing: 0.08em; color: var(--accent); }
.qa-state { font-size: 12px; color: var(--muted); text-align: right; }
.qa-question {
  margin-top: 8px; padding: 8px 10px;
  border-left: 3px solid var(--accent);
  border-radius: 0 8px 8px 0;
  background: var(--accent-soft);
  font-size: 13px; line-height: 1.55; color: var(--text);
  word-break: break-word;
}
.qa-hands { margin-top: 8px; display: grid; gap: 6px; }
.qa-teacher-ask { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-top: 8px; }
.qa-teacher-ask input {
  flex: 1 1 140px; min-width: 100px;
  padding: 7px 10px; border-radius: 9px;
  border: 1px solid var(--line-strong);
  background: #0b1422; color: var(--text); font-size: 12.5px; outline: none;
}
.qa-teacher-ask input:focus { border-color: rgba(53, 224, 197, 0.45); }
.qa-hand-row {
  display: grid; grid-template-columns: 1fr auto auto;
  align-items: center; gap: 8px;
  padding: 7px 9px; border-radius: 9px;
  background: rgba(255, 255, 255, 0.04);
  font-size: 12.5px;
}
.qa-hand-row .name { color: var(--text); }
.qa-hand-row .time { color: var(--dim); font-size: 11px; }
.qa-empty { padding: 8px 2px; font-size: 12px; color: var(--dim); }
.qa-student { display: flex; align-items: center; gap: 10px; margin-top: 10px; }
.qa-tip { font-size: 12px; color: var(--muted); }
.qa-btn {
  border: 1px solid var(--line-strong);
  background: rgba(255, 255, 255, 0.06);
  color: var(--text);
  border-radius: 9px;
  padding: 6px 12px;
  font-size: 12.5px;
  white-space: nowrap;
}
.qa-btn:hover { border-color: rgba(53, 224, 197, 0.5); }
.qa-btn:disabled { opacity: 0.45; cursor: not-allowed; }
.qa-btn.rec { border-color: rgba(255, 111, 111, 0.5); background: rgba(255, 111, 111, 0.12); }
.qa-btn.ghost { background: transparent; }
.qa-answer { margin-top: 10px; padding: 10px; border-radius: 10px; background: rgba(255, 111, 111, 0.06); border: 1px solid rgba(255, 111, 111, 0.18); }
.qa-answer-head { display: flex; align-items: center; justify-content: space-between; font-size: 12.5px; }
.qa-count { color: var(--warn); font-variant-numeric: tabular-nums; }
.qa-answer-actions { display: flex; gap: 8px; margin-top: 8px; }
.qa-wave { display: block; width: 100%; height: 36px; margin-top: 8px; border-radius: 8px; background: rgba(0, 0, 0, 0.25); }
.qa-text-answer { margin-top: 10px; padding: 10px; border-radius: 10px; background: rgba(255, 255, 255, 0.035); border: 1px solid var(--line); }
.qa-text {
  width: 100%; box-sizing: border-box; resize: vertical;
  min-height: 62px; max-height: 160px;
  padding: 8px 10px; border-radius: 8px;
  border: 1px solid var(--line-strong); background: rgba(0, 0, 0, 0.28);
  color: var(--text); font-size: 12.5px; line-height: 1.6; font-family: var(--font);
  outline: none;
}
.qa-text:focus { border-color: rgba(53, 224, 197, 0.45); }
.qa-text-foot { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-top: 6px; }
.qa-text-hint { font-size: 11.5px; color: var(--muted); line-height: 1.5; }
.qa-live { margin-top: 10px; padding: 9px 10px; border-radius: 10px; background: rgba(53, 224, 197, 0.06); border: 1px solid rgba(53, 224, 197, 0.16); }
.qa-live-head { display: flex; align-items: center; justify-content: space-between; font-size: 12.5px; }
.qa-live-state { color: var(--accent); }
.qa-live-text { margin-top: 5px; font-size: 12.5px; line-height: 1.6; color: var(--muted); word-break: break-word; }
.qa-comment-text {
  margin-top: 7px; padding: 7px 9px; max-height: 160px; overflow: auto;
  border-left: 2px solid var(--accent); border-radius: 0 8px 8px 0;
  background: rgba(53, 224, 197, 0.07); font-size: 12.5px; line-height: 1.7; color: var(--text);
  word-break: break-word;
}
.qa-comment-audio { margin-top: 8px; padding-top: 8px; border-top: 1px dashed rgba(53, 224, 197, 0.25); }
.qa-comment-audio-label { display: block; margin-bottom: 5px; font-size: 11px; color: var(--accent); }
.qa-comment-audio audio { display: block; width: 100%; height: 34px; }
.qa-actions { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-top: 10px; }
.qa-select {
  flex: 1 1 110px; min-width: 90px;
  padding: 6px 8px; border-radius: 9px;
  border: 1px solid var(--line-strong);
  background: #0b1422; color: var(--text); font-size: 12.5px;
}

/* ============================ 登录门 ============================ */
.auth-gate {
  position: fixed; inset: 0; z-index: 90;
  display: grid; place-items: center;
  padding: 24px;
  background:
    radial-gradient(900px 480px at 20% 0%, rgba(53, 224, 197, 0.12), transparent 60%),
    radial-gradient(800px 440px at 85% 10%, rgba(124, 156, 255, 0.12), transparent 55%),
    rgba(4, 8, 14, 0.92);
  backdrop-filter: blur(10px);
}
.auth-card {
  width: min(420px, 100%);
  background: linear-gradient(180deg, rgba(18, 31, 51, 0.96), rgba(11, 20, 34, 0.96));
  border: 1px solid var(--line-strong);
  border-radius: 20px;
  box-shadow: var(--shadow);
  padding: 28px;
}
.auth-head { display: flex; align-items: center; gap: 14px; margin-bottom: 22px; }
.auth-head .brand-mark { width: 42px; height: 42px; font-size: 22px; }
.auth-tabs {
  display: grid; grid-template-columns: 1fr 1fr; gap: 6px;
  padding: 5px; margin-bottom: 20px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--line);
  border-radius: 12px;
}
.auth-tab {
  border: 0; background: transparent; color: var(--muted);
  padding: 9px 8px; border-radius: 9px; font-size: 13.5px;
  transition: background 0.16s ease, color 0.16s ease;
}
.auth-tab:hover { color: var(--text); }
.auth-tab.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
.auth-pane { display: none; flex-direction: column; gap: 14px; }
.auth-pane.active { display: flex; }
.auth-pane label { display: flex; flex-direction: column; gap: 7px; font-size: 12.5px; color: var(--muted); }
.auth-pane input {
  width: 100%; padding: 11px 13px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--line-strong);
  border-radius: 11px; font-size: 14.5px; color: var(--text);
  outline: none; transition: border-color 0.16s ease;
}
.auth-pane input:focus { border-color: var(--accent); }
.auth-pane .btn { margin-top: 4px; }
.auth-note { margin: 2px 0 0; font-size: 11.5px; line-height: 1.6; color: var(--dim); }
.auth-msg {
  margin-top: 16px; padding: 10px 12px; border-radius: 10px;
  font-size: 12.5px; line-height: 1.6;
  background: rgba(255, 111, 111, 0.10);
  border: 1px solid rgba(255, 111, 111, 0.28);
  color: #ffb3b3;
}
.auth-msg.ok {
  background: var(--accent-soft);
  border-color: rgba(53, 224, 197, 0.30);
  color: var(--accent);
}

/* ==================== 练习库（题库只存本机浏览器） ==================== */
.modal-card.wide { width: min(900px, 100%); }
.bank-top { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 14px; }
.bank-tip {
  font-size: 11.5px; color: var(--dim); line-height: 1.9;
  background: rgba(53, 224, 197, 0.05); border: 1px solid rgba(53, 224, 197, 0.16);
  border-radius: 10px; padding: 10px 13px; margin-bottom: 14px;
}
.bank-tip b { color: var(--accent); font-weight: 500; }
.bank-list { display: flex; flex-direction: column; gap: 10px; }
.paper { border: 1px solid var(--line); border-radius: 12px; padding: 12px 14px; background: rgba(255, 255, 255, 0.03); }
.paper-head { display: flex; justify-content: space-between; gap: 10px; align-items: flex-start; }
.paper-name { font-size: 13.5px; line-height: 1.5; }
.paper-meta { font-size: 11px; color: var(--dim); margin-top: 5px; line-height: 1.7; }
.paper-acts { display: flex; gap: 6px; flex: none; flex-wrap: wrap; justify-content: flex-end; }
.mini-btn {
  font-size: 11px; border: 1px solid var(--line); background: transparent; color: var(--muted);
  padding: 4px 10px; border-radius: 999px; white-space: nowrap;
}
.mini-btn:hover { color: var(--accent); border-color: rgba(53, 224, 197, 0.4); }
.mini-btn.danger:hover { color: var(--danger); border-color: rgba(255, 111, 111, 0.4); }
.mini-btn.on { color: var(--accent); border-color: rgba(53, 224, 197, 0.45); background: var(--accent-soft); }

/* 校对卡片 */
.qedit {
  border: 1px solid var(--line); border-radius: 12px; padding: 12px 14px;
  margin-bottom: 10px; background: rgba(255, 255, 255, 0.02);
}
.qedit.warn { border-color: rgba(255, 190, 118, 0.35); background: rgba(255, 190, 118, 0.04); }
.qedit-head { display: flex; align-items: center; gap: 8px; margin-bottom: 10px; }
.qedit-no { font-size: 11px; color: var(--dim); flex: none; min-width: 38px; }
.qedit-head select {
  background: rgba(0, 0, 0, 0.3); border: 1px solid var(--line); color: var(--text);
  border-radius: 8px; padding: 5px 8px; font-size: 11.5px; outline: none;
}
.qedit-head .spacer { flex: 1; }
.qedit-row { display: flex; gap: 9px; margin-top: 7px; align-items: flex-start; }
.qedit-row > span { flex: none; width: 46px; font-size: 11px; color: var(--dim); padding-top: 10px; }
.qedit-row textarea, .qedit-row input { flex: 1; }
.qedit-row textarea { min-height: 44px; font-size: 12.5px; }
.qedit-warn { font-size: 11px; color: var(--warn); margin-top: 7px; line-height: 1.7; }

/* 选题发布 */
.pub-tabs { display: flex; gap: 6px; margin-bottom: 14px; }
.pub-tab {
  flex: 1; border: 1px solid var(--line); background: transparent; color: var(--muted);
  padding: 9px; border-radius: 9px; font-size: 12.5px;
}
.pub-tab.active { border-color: rgba(53, 224, 197, 0.4); color: var(--accent); background: var(--accent-soft); }
.pub-papers { display: flex; gap: 6px; overflow-x: auto; padding-bottom: 8px; margin-bottom: 10px; }
.qlist { max-height: 230px; overflow: auto; display: flex; flex-direction: column; gap: 6px; }
.qitem {
  border: 1px solid var(--line); border-radius: 10px; padding: 9px 11px;
  font-size: 12px; color: var(--muted); cursor: pointer; line-height: 1.6;
}
.qitem:hover { border-color: var(--line-strong); }
.qitem.active { border-color: rgba(53, 224, 197, 0.45); background: var(--accent-soft); color: var(--text); }
.qitem b { color: var(--indigo); font-weight: 500; font-size: 10.5px; margin-right: 6px; }
.pub-preview {
  margin-top: 12px; border: 1px dashed var(--line-strong); border-radius: 10px;
  padding: 12px 14px; font-size: 12px; line-height: 1.85; color: var(--muted); max-height: 240px; overflow: auto;
}

/* 参考答案块 */
.ref-box {
  border: 1px solid rgba(255, 190, 118, 0.28); background: rgba(255, 190, 118, 0.06);
  border-radius: 10px; padding: 11px 13px; margin-top: 12px; font-size: 12px; line-height: 1.85;
}
.ref-box h5 { margin: 0 0 6px; font-size: 10.5px; color: var(--warn); font-weight: 500; letter-spacing: 0.6px; }
.ref-box .ana { color: var(--muted); margin-top: 9px; padding-top: 9px; border-top: 1px dashed rgba(255, 190, 118, 0.22); }
.ref-box .ana h5 { color: var(--dim); }

/* 学生作答选项 */
.opt-check {
  display: flex; gap: 10px; align-items: flex-start; padding: 11px 13px;
  border: 1px solid var(--line); border-radius: 10px; margin-bottom: 8px;
  cursor: pointer; font-size: 13px; color: var(--text); line-height: 1.6;
}
.opt-check:hover { border-color: var(--line-strong); }
.opt-check.on { border-color: rgba(53, 224, 197, 0.45); background: var(--accent-soft); }
.opt-check input { accent-color: #35e0c5; margin-top: 3px; flex: none; }
.opt-check .k { color: var(--indigo); font-weight: 500; flex: none; }

/* 批阅反馈 */
.fb-card {
  border: 1px solid rgba(53, 224, 197, 0.25); background: rgba(53, 224, 197, 0.05);
  border-radius: 14px; padding: 16px 18px; margin-top: 16px;
}
.fb-top { display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap; }
.fb-score { font-size: 26px; color: var(--warn); font-weight: 600; }
.fb-score small { font-size: 12px; color: var(--dim); font-weight: 400; margin-left: 3px; }
.fb-level {
  font-size: 11.5px; color: var(--accent); border: 1px solid rgba(53, 224, 197, 0.35);
  border-radius: 999px; padding: 2px 10px;
}
.fb-level.bad { color: var(--danger); border-color: rgba(255, 111, 111, 0.35); }
.fb-sec { margin-top: 13px; font-size: 12.5px; line-height: 1.9; color: var(--muted); }
.fb-sec h6 { margin: 0 0 5px; font-size: 10.5px; color: var(--dim); font-weight: 500; letter-spacing: 0.6px; }
.fb-hit span, .fb-miss span {
  display: inline-block; border-radius: 6px; padding: 2px 8px; margin: 2px 5px 2px 0;
  font-size: 11.5px; line-height: 1.7;
}
.fb-hit span { background: rgba(53, 224, 197, 0.14); color: #7ff0dc; }
.fb-miss span { background: rgba(255, 190, 118, 0.14); color: var(--warn); }
.fb-pending { font-size: 12px; color: var(--dim); display: flex; align-items: center; gap: 8px; }
.fb-pending i { width: 6px; height: 6px; border-radius: 50%; background: var(--accent); animation: pulse 1.2s infinite; }

/* 讲评面板 */
.work-ref { margin-top: 14px; }
.stat-row.correct .stat-top span:first-child { color: var(--accent); }
.stat-row.correct .stat-bar i { background: linear-gradient(90deg, #35e0c5, #3ef0a0); }
.work-mat {
  font-size: 11.5px; color: var(--dim); line-height: 1.9; max-height: 120px; overflow: auto;
  background: rgba(0, 0, 0, 0.22); border-left: 2px solid var(--line-strong);
  padding: 8px 10px; border-radius: 0 8px 8px 0; margin-bottom: 12px; white-space: pre-wrap;
}