:root {
  --bg: #0b0f1a;
  --bg-soft: #131a2b;
  --panel: #1a2338;
  --panel-2: #212c45;
  --line: #2c3a58;
  --txt: #e8eefc;
  --txt-dim: #97a5c4;
  --txt-mute: #6b7a9c;
  --blue: #4f7cff;
  --purple: #8b5cf6;
  --cyan: #22d3ee;
  --green: #34d399;
  --amber: #fbbf24;
  --red: #f87171;
  --radius: 14px;
  --radius-sm: 9px;
  --shadow: 0 8px 28px rgba(0, 0, 0, .35);
  --font: "Microsoft YaHei", "PingFang SC", -apple-system, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--bg);
  color: var(--txt);
  font-family: var(--font);
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
}

body { overflow: hidden; }

button, input, select, textarea {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
}

button { cursor: pointer; border: none; background: none; }
button:disabled { opacity: .45; cursor: not-allowed; }

a { color: var(--blue); text-decoration: none; }

/* ============ 通用布局 ============ */

.app { display: flex; height: 100vh; }

.sidebar {
  width: 300px;
  flex-shrink: 0;
  background: var(--bg-soft);
  border-right: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
}

.brand {
  padding: 18px 20px 14px;
  border-bottom: 1px solid var(--line);
  flex-shrink: 0;
}
.brand h1 {
  margin: 0 0 4px;
  font-size: 16px;
  font-weight: 700;
  background: linear-gradient(90deg, var(--blue), var(--purple));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.brand .sub { font-size: 12px; color: var(--txt-mute); }

.scroll { overflow-y: auto; overflow-x: hidden; flex: 1; }
.scroll::-webkit-scrollbar { width: 8px; }
.scroll::-webkit-scrollbar-thumb { background: #2f3d5c; border-radius: 4px; }
.scroll::-webkit-scrollbar-thumb:hover { background: #3d4d72; }

/* ============ 环节时间轴 ============ */

.timeline { padding: 10px; }

.tl-group {
  font-size: 11px;
  color: var(--txt-mute);
  padding: 12px 10px 6px;
  letter-spacing: 1px;
  font-weight: 600;
}

.stage-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 11px;
  border-radius: var(--radius-sm);
  margin-bottom: 4px;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all .15s;
  position: relative;
}
.stage-item:hover { background: var(--panel); }
.stage-item.active {
  background: linear-gradient(90deg, rgba(79,124,255,.18), rgba(139,92,246,.08));
  border-color: rgba(79,124,255,.45);
}
.stage-item.done .stg-idx { background: var(--green); color: #06281a; }

.stg-idx {
  width: 24px; height: 24px;
  flex-shrink: 0;
  border-radius: 50%;
  background: var(--panel-2);
  color: var(--txt-dim);
  display: flex; align-items: center; justify-content: center;
  font-size: 12px; font-weight: 700;
  margin-top: 1px;
}
.stage-item.active .stg-idx { background: var(--blue); color: #fff; }

.stg-body { min-width: 0; flex: 1; }
.stg-title {
  font-size: 13.5px; font-weight: 600; margin-bottom: 3px;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.stg-meta {
  font-size: 11px; color: var(--txt-mute);
  display: flex; align-items: center; gap: 6px; flex-wrap: wrap;
}
.stg-badge {
  background: var(--panel-2);
  padding: 1.5px 6px;
  border-radius: 5px;
  font-size: 10.5px;
}
.stg-role { display: flex; align-items: center; gap: 4px; }
.dot { width: 7px; height: 7px; border-radius: 50%; flex-shrink: 0; }

/* ============ 顶栏 ============ */

.topbar {
  /* 字号调大后按钮会变宽：让顶栏能换行、高度自适应，别把按钮挤出屏幕 */
  min-height: 58px;
  flex-shrink: 0;
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  padding: 6px 18px;
  gap: 14px;
  background: var(--bg-soft);
}
.topbar .title { font-weight: 700; font-size: 15px; }
.topbar .meta { font-size: 12px; color: var(--txt-mute); }
.spacer { flex: 1; }

.chip {
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 11.5px;
  background: var(--panel-2);
  border: 1px solid var(--line);
  display: inline-flex; align-items: center; gap: 5px;
  white-space: nowrap;
}
.chip.ok { background: rgba(52,211,153,.14); border-color: rgba(52,211,153,.4); color: #6ee7b7; }
.chip.warn { background: rgba(251,191,36,.14); border-color: rgba(251,191,36,.4); color: #fcd34d; }
.chip.err { background: rgba(248,113,113,.14); border-color: rgba(248,113,113,.4); color: #fca5a5; }

/* ============ 按钮 ============ */

.btn {
  padding: 8px 15px;
  border-radius: var(--radius-sm);
  background: var(--panel-2);
  border: 1px solid var(--line);
  font-size: 13px;
  font-weight: 500;
  transition: all .15s;
  display: inline-flex; align-items: center; gap: 6px;
}
.btn:hover:not(:disabled) { background: #2a3752; border-color: #3d4d72; }
.btn.primary {
  background: linear-gradient(135deg, var(--blue), var(--purple));
  border-color: transparent; color: #fff; font-weight: 600;
}
.btn.primary:hover:not(:disabled) { filter: brightness(1.12); }
.btn.ghost { background: transparent; }
.btn.danger { color: var(--red); border-color: rgba(248,113,113,.35); }
.btn.sm { padding: 5px 10px; font-size: 12px; }
.btn.lg { padding: 12px 22px; font-size: 15px; }
/* ★ .btn 自带 display:inline-flex，会把 [hidden] 的浏览器默认样式盖掉，
   于是"用 hidden 属性藏按钮"会失效 —— 显式补一条 */
.btn[hidden] { display: none; }

/* 课堂快捷按钮（quickReplies）：投在屏幕上学生也要看得见，
   所以单独放大，不能用 .btn.sm 那种 12px 的小字 */
.quick-btn {
  font-weight: 600;
  font-size: calc(15px * var(--fs, 1));
  padding: calc(8px * var(--fs, 1)) calc(16px * var(--fs, 1));
}

/* ============ 舞台（大屏对话区） ============ */

.stage {
  flex: 1;
  overflow-y: auto;
  padding: 22px 26px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.msg { display: flex; gap: 12px; max-width: 88%; }
.msg.user { align-self: flex-end; flex-direction: row-reverse; }

/* ============ 对话组：一个话题 + 它的所有回应 ============
   ★ 回应叠在被回应那条的下面，不另起一条气泡 —— 一排排气泡看不出"谁在回谁"。
     组内回应**平级**排列（不做二级嵌套）：缩进两三层之后投屏上根本分不清谁在回谁。 */
.thread {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.thread-replies {
  display: flex;
  flex-direction: column;
  gap: 7px;
  /* 缩进对齐到头像右侧，并用一条竖线表明"这些是在回上面那条" */
  margin-left: 50px;
  padding-left: 14px;
  border-left: 2px solid rgba(34, 211, 238, .22);
}
.msg.in-group { max-width: 100%; }
.msg.in-group .who { color: var(--txt-dim); }
.msg.in-group .who::before { content: '↩ 回应 · '; color: var(--cyan); font-weight: 600; }
.msg.in-group .bubble { background: var(--panel-2); }
/* 组内「正在思考」的占位：小一号，别喧宾夺主 */
.msg.in-wait.in-group .bubble { padding: 9px 14px; }

.avatar {
  width: 38px; height: 38px;
  border-radius: 11px;
  flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 15px; color: #fff;
}

.bubble {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 15px;
  padding: 13px 17px;
  font-size: 17px;
  line-height: 1.72;
  white-space: pre-wrap;
  word-break: break-word;
  box-shadow: var(--shadow);
}
.msg.user .bubble {
  background: linear-gradient(135deg, rgba(79,124,255,.2), rgba(139,92,246,.14));
  border-color: rgba(79,124,255,.35);
}
.msg .who {
  font-size: 11.5px; color: var(--txt-mute);
  margin-bottom: 5px; font-weight: 600;
}
.msg.user .who { text-align: right; }

.bubble .tag-line {
  display: block; margin-top: 8px; padding-top: 7px;
  border-top: 1px dashed var(--line);
  font-size: 11px; color: var(--txt-mute);
}

/* discussion 多路发言用更紧凑的卡片 */
.msg.discussion { max-width: 46%; }
.msg.discussion .bubble { font-size: 15px; padding: 11px 14px; }

/* ============ 每条气泡自带的朗读控件 ============
   ★ 进度线贴在**它自己**的文字下面，而不是另立一根全局进度条。
     常态只露一个小喇叭，鼠标划过或正在朗读时才完整显形 ——
     二十来条发言每条都挂一整排按钮会很吵。 */
.bub-tools {
  display: flex; align-items: center; gap: 8px;
  margin-top: 7px;
  opacity: .3;
  transition: opacity .15s;
}
.msg:hover .bub-tools,
.msg.speaking .bub-tools,
.slide-card:hover .bub-tools { opacity: 1; }
.bub-play {
  width: 24px; height: 24px; flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  border-radius: 50%;
  background: var(--panel-2); border: 1px solid var(--line);
  color: var(--txt-dim); font-size: 11px; line-height: 1;
  cursor: pointer; transition: all .15s;
}
.bub-play:hover { border-color: var(--cyan); color: var(--cyan); }
.msg.speaking .bub-play { border-color: var(--cyan); color: var(--cyan); }
/* 没自动朗读时闪一下，告诉老师"这条能点着听" */
.bub-play.pulse { animation: bubPulse 1.2s ease-in-out 2; border-color: var(--amber); color: var(--amber); }
@keyframes bubPulse { 0%, 100% { transform: scale(1); } 50% { transform: scale(1.18); } }
.bub-state { font-size: 11px; color: var(--cyan); }
.bub-reply {
  margin-left: auto;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 11.5px;
  background: var(--panel-2); border: 1px solid var(--line);
  color: var(--txt-dim); cursor: pointer; transition: all .15s;
}
.bub-reply:hover { border-color: var(--cyan); color: var(--cyan); background: rgba(34,211,238,.1); }
.bub-meter {
  flex: 1; height: 3px; min-width: 40px;
  background: var(--panel-2); border-radius: 2px; overflow: hidden;
}
.bub-meter i { display: block; height: 100%; width: 0; background: var(--cyan); transition: width .2s linear; }
/* 正在朗读的那一条整条发光 —— 一眼知道在念哪句 */
.msg.speaking .bubble {
  border-color: rgba(34,211,238,.55);
  box-shadow: 0 0 0 1px rgba(34,211,238,.35), 0 0 22px rgba(34,211,238,.18);
}
.slide-card.speaking { border-color: rgba(34,211,238,.55); box-shadow: 0 0 22px rgba(34,211,238,.18); }
/* 主按钮切到「下一步」时换个颜色，避免跟"执行本环节"混淆 */
#btnRun.next { background: var(--panel-2); color: var(--txt); border: 1px solid var(--cyan); }

/* 思考中 */
.typing { display: flex; gap: 5px; padding: 6px 2px; }
.typing span {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--txt-mute);
  animation: blink 1.3s infinite;
}
.typing span:nth-child(2) { animation-delay: .18s; }
.typing span:nth-child(3) { animation-delay: .36s; }
@keyframes blink { 0%, 60%, 100% { opacity: .25; } 30% { opacity: 1; } }

/* ============ 控制区 ============ */

.console {
  flex-shrink: 0;
  border-top: 1px solid var(--line);
  background: var(--bg-soft);
  padding: 13px 18px;
}

.console-row { display: flex; gap: 10px; align-items: flex-start; }
.console-row + .console-row { margin-top: 10px; }

.field {
  flex: 1;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 10px 13px;
  color: var(--txt);
  outline: none;
  resize: none;
  line-height: 1.6;
  font-size: 14.5px;
  min-height: 44px;
  max-height: 130px;
}
.field:focus { border-color: var(--blue); }
.field::placeholder { color: var(--txt-mute); }

.action-bar { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }

.hint {
  font-size: 11.5px; color: var(--txt-mute);
  display: flex; align-items: center; gap: 6px; flex-wrap: wrap;
}

.img-strip { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }
.img-thumb {
  width: 62px; height: 62px; object-fit: cover;
  border-radius: 9px; border: 1px solid var(--line);
}
.img-wrap { position: relative; }
.img-wrap .del {
  position: absolute; top: -6px; right: -6px;
  width: 20px; height: 20px; border-radius: 50%;
  background: var(--red); color: #fff; font-size: 12px;
  display: flex; align-items: center; justify-content: center;
}

/* ============ 空状态 ============ */

.empty {
  flex: 1; display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  gap: 14px; color: var(--txt-mute); text-align: center; padding: 40px;
}
.empty .big { font-size: 42px; opacity: .35; }
.empty h3 { margin: 0; color: var(--txt-dim); font-size: 16px; }

/* ============ 弹窗 ============ */

.modal-mask {
  position: fixed; inset: 0;
  background: rgba(4, 7, 14, .78);
  display: flex; align-items: center; justify-content: center;
  z-index: 100; padding: 24px;
  backdrop-filter: blur(3px);
}
.modal {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 18px;
  width: 100%; max-width: 620px;
  max-height: 86vh;
  display: flex; flex-direction: column;
  box-shadow: 0 20px 60px rgba(0,0,0,.5);
}
.modal-head {
  padding: 16px 20px; border-bottom: 1px solid var(--line);
  display: flex; align-items: center; gap: 10px; flex-shrink: 0;
}
.modal-head h3 { margin: 0; font-size: 15.5px; flex: 1; }
.modal-body { padding: 18px 20px; overflow-y: auto; }
.modal-foot {
  padding: 13px 20px; border-top: 1px solid var(--line);
  display: flex; gap: 9px; justify-content: flex-end; flex-shrink: 0;
}

.close-x {
  width: 28px; height: 28px; border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  color: var(--txt-mute); font-size: 17px;
}
.close-x:hover { background: var(--panel-2); color: var(--txt); }

/* ============ 表单 ============ */

.form-row { margin-bottom: 15px; }
.form-row label {
  display: block; font-size: 12.5px; color: var(--txt-dim);
  margin-bottom: 6px; font-weight: 600;
}
.form-row .desc { font-size: 11.5px; color: var(--txt-mute); margin-top: 5px; line-height: 1.55; }
.input, .select, .textarea {
  width: 100%;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 9px 12px;
  outline: none;
  transition: border-color .15s;
}
.input:focus, .select:focus, .textarea:focus { border-color: var(--blue); }
.textarea { resize: vertical; min-height: 88px; line-height: 1.65; font-size: 14px; }
.textarea.code { font-family: "Cascadia Code", Consolas, monospace; font-size: 12.5px; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }

.toast {
  position: fixed; bottom: 24px; left: 50%;
  transform: translateX(-50%);
  background: var(--panel-2);
  border: 1px solid var(--line);
  padding: 11px 20px; border-radius: 11px;
  font-size: 13.5px; z-index: 200;
  box-shadow: 0 10px 34px rgba(0,0,0,.45);
  max-width: 80vw;
}
.toast.ok { border-color: rgba(52,211,153,.5); color: #6ee7b7; }
.toast.err { border-color: rgba(248,113,113,.5); color: #fca5a5; }

/* ============ 幻灯片 ============ */

.slide-card {
  align-self: center;
  width: min(880px, 92%);
  background: linear-gradient(160deg, rgba(79,124,255,.12), rgba(139,92,246,.07));
  border: 1px solid rgba(79,124,255,.35);
  border-radius: 18px;
  padding: 26px 32px;
  box-shadow: 0 14px 44px rgba(0,0,0,.4);
}
.slide-title {
  font-size: 26px; font-weight: 700; line-height: 1.45;
  margin-bottom: 16px; letter-spacing: .5px;
}
.slide-bullets { display: flex; flex-direction: column; gap: 11px; }
.slide-bullets li {
  list-style: none;
  font-size: 18px; line-height: 1.7;
  padding-left: 20px; position: relative;
}
.slide-bullets li::before {
  content: '▸';
  position: absolute; left: 0;
  color: var(--cyan); font-weight: 700;
}
.slide-note {
  margin-top: 16px; padding-top: 12px;
  border-top: 1px dashed var(--line);
  font-size: 14px; color: var(--txt-dim); line-height: 1.7;
}
.slide-page {
  margin-top: 14px; font-size: 11.5px; color: var(--txt-mute);
  text-align: right;
}

/* 表格布局 */
.slide-table { width: 100%; border-collapse: collapse; font-size: 16px; }
.slide-table th, .slide-table td {
  border: 1px solid var(--line);
  padding: 9px 12px; text-align: left; line-height: 1.6;
}
.slide-table th { background: rgba(255,255,255,.05); font-weight: 600; }

/**
 * 朗读控制条已删除。
 * 播放/暂停/进度都归每一条发言自己（.bub-tools / .bub-meter），
 * 全局只剩顶栏一个「⏹ 停止朗读」，朗读时才出现。
 * 原来那条横贯屏幕的条既占地方，又会在朗读刚启动时闪一下，看着像故障。
 */

/* ============ 思考折叠区 ============ */

.thinking-box {
  align-self: flex-end;
  max-width: 78%;
  background: rgba(139, 92, 246, .09);
  border: 1px dashed rgba(139, 92, 246, .4);
  border-radius: var(--radius-sm);
  padding: 9px 14px;
  margin-bottom: 4px;
}
.thinking-box .th-head {
  font-size: 11.5px; color: #b79cf5; cursor: pointer;
  display: flex; align-items: center; gap: 6px; user-select: none;
}
.thinking-box .th-body {
  font-size: 12px; color: var(--txt-mute);
  line-height: 1.65; margin-top: 7px;
  max-height: 150px; overflow-y: auto;
  white-space: pre-wrap;
}

/* ============ 生成中的耗时提示 ============ */

.gen-hint {
  align-self: center;
  font-size: 11.5px;
  color: var(--txt-mute);
  display: flex; align-items: center; gap: 8px;
  padding: 4px 12px;
  background: var(--bg-soft);
  border-radius: 20px;
  border: 1px solid var(--line);
}
.gen-hint b { color: var(--txt-dim); font-variant-numeric: tabular-nums; }
.gen-hint .slow { color: var(--amber); }

/* 打字机光标 */
.cursor-blink {
  display: inline-block; width: 2px; height: 1em;
  background: var(--cyan);
  vertical-align: text-bottom;
  margin-left: 2px;
  animation: blink 1s steps(2) infinite;
}

/* ============ 日志面板 ============ */

.log-panel {
  position: fixed;
  right: 16px; bottom: 16px;
  width: 640px; max-width: 92vw;
  max-height: 62vh;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 20px 60px rgba(0, 0, 0, .55);
  display: none;
  flex-direction: column;
  z-index: 150;
}
.log-panel.open { display: flex; }
.log-head {
  padding: 11px 14px; border-bottom: 1px solid var(--line);
  display: flex; align-items: center; gap: 9px; flex-shrink: 0;
}
.log-head .t { font-size: 13px; font-weight: 700; flex: 1; }
.log-tools { display: flex; gap: 6px; align-items: center; }
.log-body {
  flex: 1; overflow-y: auto; padding: 8px 0;
  font-family: "Cascadia Code", Consolas, monospace;
  font-size: 11.5px; line-height: 1.6;
}
.log-line {
  padding: 2px 14px;
  display: flex; gap: 9px;
  border-left: 2px solid transparent;
}
.log-line:hover { background: var(--panel-2); }
.log-line .lt { color: var(--txt-mute); flex-shrink: 0; }
.log-line .ll {
  width: 42px; flex-shrink: 0;
  font-size: 10px; font-weight: 700;
}
.log-line .lm { flex: 1; word-break: break-word; }
.log-line .lx { color: var(--txt-mute); font-size: 10.5px; }
.log-line.error { border-left-color: var(--red); background: rgba(248,113,113,.07); }
.log-line.error .ll { color: var(--red); }
.log-line.warn { border-left-color: var(--amber); }
.log-line.warn .ll { color: var(--amber); }
.log-line.info .ll { color: var(--cyan); }
.log-line.debug .ll { color: var(--txt-mute); }

/* 耗时统计表 */
.log-stats {
  border-top: 1px solid var(--line);
  padding: 10px 14px; flex-shrink: 0;
  max-height: 158px; overflow-y: auto;
}
/* ---- 对话留痕（prompt / reply / guard）：可展开、可复制 ---- */
.log-panel.dialog-only .log-line:not(.dialog) { display: none; }
.log-line.dialog { padding: 0; }
.log-line.dialog details { padding: 0; }
.log-line.dialog summary {
  display: flex; gap: 7px; align-items: baseline;
  padding: 4px 8px; cursor: pointer; list-style: none;
}
.log-line.dialog summary::-webkit-details-marker { display: none; }
.log-line.dialog summary::before { content: '▸'; color: var(--txt-mute); font-size: 10px; }
.log-line.dialog details[open] summary::before { content: '▾'; }
/* 三类各自一个色条，扫一眼就知道是哪一段 */
.log-line.dialog-prompt { border-left: 2px solid var(--blue); }
.log-line.dialog-reply { border-left: 2px solid var(--cyan); }
.log-line.dialog-guard { border-left: 2px solid var(--amber); }
.log-line.dialog-prompt .ll { color: #93b4ff; }
.log-line.dialog-reply .ll { color: var(--cyan); }
.log-line.dialog-guard .ll { color: var(--amber); }
.log-pre {
  margin: 0 8px 8px; padding: 9px 11px;
  max-height: 46vh; overflow: auto;
  background: var(--bg-soft); border: 1px solid var(--line);
  border-radius: 8px;
  font-family: "Cascadia Code", Consolas, monospace;
  font-size: 11.5px; line-height: 1.65;
  color: var(--txt-dim); white-space: pre-wrap; word-break: break-word;
}
.log-copy { margin: 0 8px 8px; }

.log-stats table { width: 100%; border-collapse: collapse; font-size: 11.5px; }
.log-stats th {
  text-align: left; color: var(--txt-mute); font-weight: 600;
  padding: 3px 6px; font-size: 10.5px;
  position: sticky; top: 0; background: var(--panel);
}
.log-stats td { padding: 3px 6px; border-top: 1px solid var(--line); }
.log-stats .num { text-align: right; font-variant-numeric: tabular-nums; }
.log-stats .slow { color: var(--amber); font-weight: 700; }

.log-count {
  font-size: 10.5px; color: var(--txt-mute);
  padding: 3px 8px; border-radius: 10px;
  background: var(--panel-2); border: 1px solid var(--line);
}

/* ============ 设置中心补充 ============ */

.voice-preview {
  display: flex; align-items: center; gap: 9px;
  margin-top: 9px;
}

/* ---- 头像选择：可展开的 emoji 面板 ---- */
.avatar-pick { display: flex; align-items: center; gap: 8px; }
.avatar-pick .input { flex: 1; min-width: 0; }
.avatar-grid {
  margin-top: 9px; padding: 10px;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  max-height: 268px; overflow-y: auto;
}
/* ★ 收起状态用 hidden 属性，并在这里显式给一条规则：
   这套样式里**没有通用的 .hidden 类**（历史上只有朗读条那条作用域规则），
   所以用 .hidden 的地方根本收不起来 —— 踩过一次。
   自带一条规则，将来谁给 .avatar-grid 加了 display 也不会把收起弄失效。 */
.avatar-grid[hidden] { display: none; }
.avatar-cat { font-size: 11px; color: var(--txt-mute); margin: 8px 0 5px; }
.avatar-cat:first-child { margin-top: 0; }
.avatar-cells {
  display: grid; gap: 5px;
  /* 自适应列数：面板宽度随窗口变，固定列数一定会挤 */
  grid-template-columns: repeat(auto-fill, minmax(34px, 1fr));
}
.avatar-cell {
  height: 34px; padding: 0;
  display: flex; align-items: center; justify-content: center;
  font-size: 17px; line-height: 1; cursor: pointer;
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: 8px;
  transition: transform .12s, border-color .12s;
}
.avatar-cell:hover { transform: translateY(-1px); border-color: var(--cyan); }
.avatar-cell.on {
  border-color: var(--cyan);
  background: rgba(34, 211, 238, .14);
}
.avatar-foot { display: flex; align-items: center; gap: 9px; margin-top: 10px; }
.switch-row {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 12px;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  margin-bottom: 10px;
}
.switch-row .sw-txt { flex: 1; }
.switch-row .sw-txt b { font-size: 13px; display: block; margin-bottom: 3px; }
.switch-row .sw-txt span { font-size: 11.5px; color: var(--txt-mute); line-height: 1.55; }

/* 开关 */
.switch { position: relative; width: 42px; height: 23px; flex-shrink: 0; }
.switch input { opacity: 0; width: 0; height: 0; }
.switch .slider {
  position: absolute; inset: 0;
  background: var(--panel-2); border-radius: 23px;
  transition: .2s; cursor: pointer;
}
.switch .slider:before {
  content: ''; position: absolute;
  width: 17px; height: 17px; left: 3px; bottom: 3px;
  background: var(--txt-mute); border-radius: 50%;
  transition: .2s;
}
.switch input:checked + .slider { background: rgba(79,124,255,.45); }
.switch input:checked + .slider:before { transform: translateX(19px); background: #fff; }

.notice {
  padding: 11px 15px; border-radius: var(--radius-sm);
  font-size: 12.5px; line-height: 1.65; margin-bottom: 15px;
  display: flex; gap: 9px; align-items: flex-start;
}
.notice.warn { background: rgba(251,191,36,.1); border: 1px solid rgba(251,191,36,.3); color: #fcd34d; }
.notice.info { background: rgba(79,124,255,.1); border: 1px solid rgba(79,124,255,.3); color: #93b4ff; }

/* ============ 投屏字号缩放 ============
   ★ 白板上"字够不够大"取决于投影仪、教室大小和学生坐多远，没有一次调对的答案。
     课堂顶栏「🔤 字号」的三档就是改这里的 --fs（由 classroom.js 写到 :root）。
   ★ 做法：只把"学生要看的东西"的尺寸统一乘 --fs，放在文件末尾覆盖原规则
     （同优先级下后者生效），而不是逐个去翻改上面的定义 ——
     这样字号策略集中在一处，一眼能看全、也好调。 */
html, body { font-size: calc(15px * var(--fs, 1)); }

/* 对话气泡 —— 学生看得最多的就是它 */
.msg .bubble { font-size: calc(17px * var(--fs, 1)); }
.msg.discussion .bubble { font-size: calc(15px * var(--fs, 1)); }
.msg .who { font-size: calc(11.5px * var(--fs, 1)); }
.tag-line { font-size: calc(11px * var(--fs, 1)); }

/* 气泡自带的朗读控件 */
.bub-state { font-size: calc(11px * var(--fs, 1)); }
.bub-reply { font-size: calc(11.5px * var(--fs, 1)); }
.bub-play {
  width: calc(24px * var(--fs, 1)); height: calc(24px * var(--fs, 1));
  font-size: calc(11px * var(--fs, 1));
}

/* 幻灯片 —— 教材原文、原理表述全靠它 */
.slide-title { font-size: calc(26px * var(--fs, 1)); }
.slide-bullets li { font-size: calc(18px * var(--fs, 1)); }
.slide-table { font-size: calc(16px * var(--fs, 1)); }
.slide-note { font-size: calc(14px * var(--fs, 1)); }
.slide-page { font-size: calc(11.5px * var(--fs, 1)); }

/* 控件与提示：老师也要看清，且投屏上学生同样看得见 */
.btn { font-size: calc(13px * var(--fs, 1)); }
.btn.sm { font-size: calc(12px * var(--fs, 1)); }
.btn.lg { font-size: calc(15px * var(--fs, 1)); }
.chip { font-size: calc(11.5px * var(--fs, 1)); }
.field { font-size: calc(14.5px * var(--fs, 1)); }
.hint { font-size: calc(11.5px * var(--fs, 1)); }
.topbar .title { font-size: calc(15px * var(--fs, 1)); }
.topbar .meta { font-size: calc(12px * var(--fs, 1)); }
.gen-hint { font-size: calc(11.5px * var(--fs, 1)); }
.empty h3 { font-size: calc(16px * var(--fs, 1)); }
.empty .big { font-size: calc(42px * var(--fs, 1)); }

/* 左侧环节时间轴 */
.stg-title { font-size: calc(13.5px * var(--fs, 1)); }
.stg-meta { font-size: calc(11px * var(--fs, 1)); }
.stg-badge { font-size: calc(10.5px * var(--fs, 1)); }