/* ============================================================
   项目A AI数学学习系统 - 全局样式
   响应式: 桌面/平板/手机 自适应
   ============================================================ */

:root {
  --primary: #3b82f6;
  --primary-dark: #2563eb;
  --primary-light: #dbeafe;
  --bg: #f5f7fa;
  --card-bg: #ffffff;
  --text: #1f2937;
  --text-sub: #6b7280;
  --border: #e5e7eb;
  --success: #16a34a;
  --warn: #d97706;
  --danger: #dc2626;
  --locked: #d1d5db;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.04);
  --success-bg: #f0fdf4;   /* 通过/成功 底色（浅色） */
  --warn-bg: #fffbeb;      /* 提示/复习 底色（浅色） */
  --bg-sub: #f5f5f5;       /* 禁用控件底色（浅色） */
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html, body {
  height: 100%;
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  background: var(--bg);
  color: var(--text);
  -webkit-tap-highlight-color: transparent;
}

#app { display: flex; flex-direction: column; height: 100%; max-width: 900px; margin: 0 auto; }

/* ---------- 顶部栏 ---------- */
#topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--primary);
  color: #fff;
  padding: clamp(8px, 2vh, 12px) clamp(10px, 3vw, 16px);
  flex: 0 0 auto;
}
#topbar-title { font-size: clamp(15px, 4vw, 18px); font-weight: 700; flex: 0 0 auto; }
#topbar-nav { display: flex; gap: 8px; flex: 1; justify-content: flex-end; min-width: 0; overflow-x: auto; }
.topbar-btn {
  background: transparent;
  border: none;
  color: #fff;
  font-size: clamp(12px, 3.2vw, 14px);
  padding: clamp(4px, 1.2vh, 6px) clamp(8px, 2.5vw, 12px);
  border-radius: 8px;
  cursor: pointer;
  white-space: nowrap;
}
.topbar-btn.active { background: rgba(255,255,255,.2); font-weight: 600; }
.topbar-btn .nav-ico { font-size: 16px; line-height: 1; }
/* 顶栏状态徽标（系统切换/自由模式/用户）与导航按钮同款样式 */
#topbar-sys, #topbar-free, #topbar-user { font-size: 16px; line-height: 1; margin-left: 6px; }
/* 平板竖屏及更窄（≤900px）：导航按钮只显示图标，顶栏不挤占 */
@media (max-width: 900px) {
  #topbar-nav { gap: 4px; }
  .topbar-btn { padding: 5px 7px; }
  .topbar-btn .nav-txt { display: none; }
}
.topbar-btn:hover { background: rgba(255,255,255,.12); }

/* 顶栏用户/系统徽标已统一为 .topbar-btn 样式（与导航按钮同款），无专用规则 */
.sys-menu {
  position: fixed; z-index: 2000;
  background: var(--card-bg); border: 1px solid var(--border);
  border-radius: 12px; box-shadow: var(--shadow);
  padding: 6px; min-width: 200px;
}
.sys-menu-item {
  display: flex; flex-direction: column; gap: 2px;
  padding: 9px 12px; border-radius: 8px; cursor: pointer;
  font-size: 14px; font-weight: 600; color: var(--text);
}
.sys-menu-item:hover { background: var(--primary-light); }
.sys-menu-item.on { background: var(--primary-light); color: var(--primary); }
.sys-menu-desc { font-size: 12px; font-weight: 400; color: var(--text-sub); }

/* ---------- 主内容区 ---------- */
#main { flex: 1 1 auto; overflow-y: auto; padding: clamp(10px, 2.5vh, 16px); }

/* ---------- 底部状态条 ---------- */
#statusbar {
  flex: 0 0 auto;
  display: flex;
  justify-content: space-between;
  padding: 6px 16px;
  font-size: 12px;
  color: var(--text-sub);
  background: var(--card-bg);
  border-top: 1px solid var(--border);
}

/* ---------- 通用组件 ---------- */
.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: clamp(12px, 3vh, 16px);
  margin: clamp(8px, 2vh, 14px) auto;
  max-width: 480px;
}
.page-title { font-size: clamp(19px, 5vw, 22px); font-weight: 700; margin-bottom: 4px; }
.page-sub { font-size: 14px; color: var(--text-sub); margin-bottom: clamp(10px, 3vh, 16px); }

.big-btn {
  display: block;
  width: 100%;
  padding: 18px;
  margin-bottom: 14px;
  border: 2px solid var(--border);
  border-radius: var(--radius);
  background: var(--card-bg);
  font-size: 17px;
  text-align: left;
  cursor: pointer;
  transition: all .15s;
}
.big-btn .btn-title { font-size: 18px; font-weight: 700; display: block; margin-bottom: 4px; }
.big-btn .btn-desc { font-size: 13px; color: var(--text-sub); display: block; }
.big-btn:hover { border-color: var(--primary); }
.big-btn.selected { border-color: var(--primary); background: var(--primary-light); }

/* 出题做题 · 选择题选项 */
.quiz-option {
  background: var(--card-bg);
  color: var(--text);
  transition: border-color .15s, background .15s;
}
.quiz-option:hover { border-color: var(--primary); }
.quiz-option.opt-selected {
  border-color: var(--primary);
  border-width: 2px;
  background: var(--primary-light);
  color: var(--primary);
  font-weight: 600;
}
.quiz-option.opt-selected::before { content: "✅ "; }

.primary-btn {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  border: none;
  padding: 12px 28px;
  font-size: 16px;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 600;
}
.primary-btn:disabled, .primary-btn.locked {
  background: var(--locked);
  cursor: not-allowed;
}
.primary-btn:hover:not(:disabled):not(.locked) { background: var(--primary-dark); }

.secondary-btn {
  display: inline-block;
  background: var(--card-bg);
  color: var(--primary);
  border: 1.5px solid var(--primary);
  padding: 10px 24px;
  font-size: 15px;
  border-radius: 10px;
  cursor: pointer;
}
.text-btn { background: none; border: none; color: var(--primary); cursor: pointer; font-size: 14px; }

.action-row { display: flex; gap: 12px; margin-top: 16px; flex-wrap: wrap; }

/* ---------- 折叠树 ---------- */
.tree { font-size: 15px; }
.tree-node { margin-bottom: 2px; }
.tree-row {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  border-radius: 8px;
  cursor: pointer;
  user-select: none;
}
.tree-row:hover { background: var(--primary-light); }
.tree-row .arrow {
  width: 14px;
  height: 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  color: var(--text-sub);
  transition: transform .15s;
  flex: 0 0 auto;
}
.tree-row.expanded .arrow { transform: rotate(90deg); }
.tree-row .t-label { font-weight: 600; flex: 0 0 auto; }
.tree-row .t-count { font-size: 12px; color: var(--text-sub); }
.tree-children { padding-left: 20px; border-left: 1px dashed var(--border); margin-left: 8px; }
.tree-node.leaf .tree-row { padding-left: 32px; }
.tree-node.leaf .tree-row:hover { background: var(--primary-light); }
.tree-node.selected > .tree-row { background: var(--primary); color: #fff; }
.tree-node.selected > .tree-row .t-count { color: #dbeafe; }

/* ---------- 阶段解锁流程 ---------- */
.stage-flow { display: flex; gap: 4px; flex-wrap: nowrap; margin-bottom: 10px; }
.stage-chip {
  flex: 1 1 0;
  min-width: 0;
  padding: 4px 2px;
  border-radius: 8px;
  font-size: 12px;
  text-align: center;
  white-space: nowrap;
  background: var(--card-bg);
  border: 1px solid var(--border);
  color: var(--text-sub);
}

/* ---------- 出题做题：一屏一题 ---------- */
.qz-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
  margin: 2px 0 8px;
}
.qz-nav-btn {
  flex: 0 0 auto;
  padding: 5px 10px;
  border-radius: 18px;
  font-size: 13px;
  border: 1.5px solid var(--border);
  background: var(--card-bg);
  color: var(--text);
  cursor: pointer;
}
.qz-nav-btn:hover:not(:disabled) { border-color: var(--primary); color: var(--primary); }
.qz-nav-btn:disabled { opacity: .4; cursor: default; }
.qz-chips {
  flex: 1 1 auto;
  display: flex;
  gap: 4px;
  flex-wrap: nowrap;
  justify-content: flex-start;
  overflow-x: auto;
  margin: 0;
  padding: 2px 0;
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}
/* 题少时居中、题多溢出时可滚到第1题（auto margin 让居中不裁剪左侧） */
.qz-chips::before { content: ''; margin-left: auto; }
.qz-chips::after { content: ''; margin-right: auto; }
.qz-chip {
  flex: 0 0 auto;
  min-width: 26px; height: 26px;
  padding: 0 5px;
  border-radius: 50%;
  border: 1.5px solid var(--border);
  background: var(--card-bg);
  color: var(--text-sub);
  font-size: 12px; font-weight: 600;
  cursor: pointer;
  line-height: 1;
}
.qz-chip.current { background: var(--primary); border-color: var(--primary); color: #fff; }
.qz-chip.done { background: var(--success); border-color: var(--success); color: #fff; }
/* 讲题页对错题号：绿✓ / 红✗（优先于 .current 的主题色，保证对错色始终可见） */
.qz-chip.sol-ok { color: var(--success); border-color: var(--success); }
.qz-chip.sol-no { color: #e11d48; border-color: #e11d48; }
.qz-chip.sol-pending { color: #d97706; border-color: #d97706; }
.qz-chip.current.sol-ok { background: var(--success); border-color: var(--success); color: #fff; }
.qz-chip.current.sol-no { background: #e11d48; border-color: #e11d48; color: #fff; }
.qz-chip.current.sol-pending { background: #d97706; border-color: #d97706; color: #fff; }
.qz-viewport { overflow: hidden; }
.qz-slide { border: 1px solid var(--border); border-radius: 12px; padding: 14px; margin-bottom: 12px; }

/* 填空题空位（题干里的可点击空格） */
.blank-slot {
  display: inline-block;
  min-width: 44px;
  margin: 0 4px;
  padding: 2px 6px;
  border: 1px solid var(--border);
  border-bottom: 2px solid var(--primary);
  border-radius: 4px;
  background: #fff;
  color: var(--text);
  font-weight: 600;
  text-align: center;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
  vertical-align: middle;
  line-height: 1.4;
}
.blank-slot.active { border: 2px solid var(--primary); background: #fff; color: var(--primary); }
.stage-chip.done { background: var(--success); border-color: var(--success); color: #fff; }
.stage-chip.current { background: var(--primary); border-color: var(--primary); color: #fff; font-weight: 600; }
/* 锁定：灰字，透明底（去掉了原来的 opacity 半透明——就是它让整个框发灰像锁，还显得文字对不上框） */
.stage-chip.locked { color: var(--text-sub); background: transparent; border-color: var(--border); opacity: 1; }
/* 解锁：白字 + 蓝色边框 */
.stage-chip.unlocked { border-color: var(--primary); color: #fff; background: transparent; cursor: pointer; }

/* ---------- 建议弹层 ---------- */
.suggestion {
  border-radius: 10px;
  padding: 8px 12px;
  font-size: 13px;
  margin-top: 8px;
  line-height: 1.6;
  /* 颜色由主题文件覆盖 */
  background: #fffbeb;
  border: 1px solid #fde68a;
  color: #92400e;
}
.suggestion .s-title { font-weight: 700; }

/* ---------- 进度/加载 ---------- */
.loading { text-align: center; padding: 40px 0; color: var(--text-sub); }
.spinner {
  width: 32px; height: 32px;
  border: 3px solid var(--primary-light);
  border-top-color: var(--primary);
  border-radius: 50%;
  margin: 0 auto 12px;
  animation: spin .8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- 提示/弹窗 ---------- */
.toast {
  position: fixed;
  top: 60px; left: 50%;
  transform: translateX(-50%);
  background: rgba(17,24,39,.92);
  color: #fff;
  padding: 10px 24px;
  border-radius: 10px;
  font-size: 14px;
  z-index: 999;
  opacity: 0;
  transition: opacity .25s;
  pointer-events: none;
  max-width: 90%;
}
.toast.show { opacity: 1; }

.modal-overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,.45);
  display: flex; align-items: center; justify-content: center;
  z-index: 1000;
  padding: 20px;
}
.modal {
  background: var(--card-bg);
  border-radius: 14px;
  padding: 24px;
  max-width: 480px;
  width: 100%;
  max-height: 80%;
  overflow-y: auto;
}
.modal h3 { font-size: 18px; margin-bottom: 12px; }
.modal p { font-size: 14px; line-height: 1.7; color: var(--text); }

/* ---------- 表单控件（深色主题适配） ---------- */
select,
input[type="text"],
input[type="number"],
input[type="password"],
input[type="tel"] {
  background: var(--card-bg, #fff);
  color: var(--text, #1a1a2e);
  border: 1px solid var(--border);
}
select option {
  background: var(--card-bg, #fff);
  color: var(--text, #1a1a2e);
}
select:focus,
input:focus {
  outline: none;
  border-color: var(--primary);
}

/* ---------- 响应式: 手机 ---------- */
@media (max-width: 600px) {
  #topbar { padding: 8px 10px; }
  #topbar-title { font-size: 15px; }
  .topbar-btn { font-size: 12px; padding: 4px 7px; }
  .topbar-btn.active { font-weight: 600; }
  #main { padding: 10px; }
  .card { padding: 14px; }
  .big-btn { padding: 14px; }
  .page-title { font-size: 19px; }
}

/* 超窄屏（如手机竖屏）顶栏进一步收紧，避免换行 */
@media (max-width: 420px) {
  #topbar-title { font-size: 14px; }
  .topbar-btn { font-size: 11px; padding: 4px 5px; }
  #topbar-nav { gap: 4px; }
}

/* ---------- 平板横屏/桌面 ---------- */
@media (min-width: 901px) {
  #app { max-width: 1000px; }
}

/* ============================================================
 * 首页三块同页堆叠（重排版）
 * 居中 + 保留图标
 * ============================================================ */
#home-specials,
#home-stage,
#home-tree { margin-top: 18px; }

.block-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 10px;
  text-align: center;
}

/* 专项三卡：横排居中 */
.specials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}
.specials-grid .big-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 14px 8px;
  gap: 4px;
  min-height: 90px;
}
.specials-grid .big-btn .btn-icon {
  font-size: 24px;
  line-height: 1;
}
.specials-grid .big-btn .btn-title {
  font-size: 15px;
  font-weight: 700;
}
.specials-grid .big-btn .btn-desc {
  font-size: 11px;
  color: var(--text-sub);
}

/* 学段三卡：横排居中 */
.stage-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}
.stage-card {
  background: var(--card-bg, #fff);
  border: 2px solid var(--border);
  border-radius: 12px;
  padding: 12px 10px;
  text-align: center;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  transition: border-color .15s, background .15s;
}
.stage-card:hover { border-color: var(--primary); }
.stage-card.selected {
  border-color: var(--primary);
  background: var(--primary-light);
}
.stage-icon { font-size: 30px; line-height: 1; }
.stage-name { font-size: 15px; font-weight: 700; }
.stage-count { font-size: 11px; color: var(--text-sub); }

/* 系统按钮（教师授课 / 自主学习）放在学段卡内 */
.sys-row {
  display: flex;
  gap: 6px;
  margin-top: 6px;
  width: 100%;
}
.sys-btn {
  flex: 1;
  padding: 6px 4px;
  font-size: 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  transition: all .15s;
}
.sys-btn:hover { border-color: var(--primary); }
.sys-btn.selected {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}
.sys-desc { font-size: 10px; opacity: .85; line-height: 1.2; }

/* 知识点树块 */
#home-tree #tree-container {
  margin: 0;
}
#home-tree .action-row {
  justify-content: center;
  margin-top: 14px;
}

/* 树节点居中显示（整体块不超过 680px） */
#home-tree .tree {
  max-width: 680px;
  margin: 0 auto;
}

/* ============================================================
 * 知识点浮层选择器（入口条 + 浮层面板，浮于首页之上不改变布局）
 * ============================================================ */
.kp-picker { position: relative; margin-top: clamp(8px, 2.2vh, 12px); }
.kp-trigger {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: clamp(10px, 2.8vh, 13px) clamp(12px, 3.5vw, 16px);
  font-size: clamp(14px, 3.8vw, 15px);
  font-weight: 700;
  border: 1.5px solid var(--border);
  border-radius: 10px;
  background: var(--card-bg);
  color: var(--text);
  cursor: pointer;
  user-select: none;
  transition: border-color .15s, background .15s;
}
.kp-trigger:hover { border-color: var(--primary); }
.kp-trigger .kp-ico { font-size: 18px; }
.kp-trigger .kp-txt { flex: 1; min-width: 0; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; color: var(--text-sub); }
.kp-trigger .kp-txt.picked { color: var(--primary); }
.kp-trigger .kp-arr { font-size: 11px; color: var(--text-sub); }

/* 浮层面板：absolute 定位，不占文档流 → 不改变首页布局 */
.kp-pop {
  position: absolute;
  left: 0;
  right: 0;
  top: calc(100% + 8px);
  z-index: 100;
  background: var(--card-bg);
  border: 1.5px solid var(--border);
  border-radius: 12px;
  box-shadow: 0 12px 36px rgba(0,0,0,.18);
  overflow: hidden;
}
.kp-pop-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  font-size: 14px;
  font-weight: 700;
  border-bottom: 1px solid var(--border);
}
.kp-close {
  background: none;
  border: none;
  font-size: 14px;
  color: var(--text-sub);
  cursor: pointer;
  padding: 2px 6px;
}
.kp-close:hover { color: var(--danger); }
.kp-crumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px;
  padding: 8px 16px;
  font-size: 12px;
  border-bottom: 1px dashed var(--border);
}
.kp-crumb-item {
  font-weight: 700;
  color: var(--primary);
  cursor: pointer;
}
.kp-crumb-item:hover { text-decoration: underline; }
.kp-crumb-item.muted { color: var(--text-sub); cursor: default; }
.kp-crumb-sep { color: var(--text-sub); }
.kp-list {
  max-height: 240px;
  overflow-y: auto;
  padding: 4px 0;
}
.kp-opt {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 11px 16px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  border-bottom: 1px dashed var(--border);
  transition: background .12s;
}
.kp-opt:last-child { border-bottom: none; }
.kp-opt:hover { background: var(--primary-light); }
.kp-opt .kp-imp {
  font-size: 11px;
  font-weight: 500;
  color: var(--text-sub);
  margin-left: auto;
  white-space: nowrap;
}
.kp-opt.empty { cursor: default; color: var(--text-sub); }

/* 滚动条（深色底） */
.kp-list::-webkit-scrollbar { width: 5px; }
.kp-list::-webkit-scrollbar-track { background: rgba(0,0,0,.15); border-radius: 3px; }
.kp-list::-webkit-scrollbar-thumb { background: var(--text-sub, #666); border-radius: 3px; }

@media (max-width: 600px) {
  .specials-grid,
  .stage-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 6px;
  }
  .specials-grid .big-btn { padding: 10px 4px; min-height: 78px; }
  .specials-grid .big-btn .btn-icon { font-size: 22px; }
  .specials-grid .big-btn .btn-title { font-size: 13px; }
  .specials-grid .big-btn .btn-desc { font-size: 10px; }
  .stage-icon { font-size: 26px; }
  .stage-name { font-size: 14px; }
  .sys-btn { font-size: 11px; padding: 5px 2px; }
}

/* ============================================================
 * 方案 B 布局（按预览版：竖排大卡 + stage-chip + 树折叠 + STAGE XP）
 * ============================================================ */
#home-specials {
  display: flex;
  flex-direction: column;
  gap: clamp(8px, 2.2vh, 10px);
}
#home-specials .big-btn {
  position: relative;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: clamp(10px, 2.6vh, 14px) clamp(12px, 3vw, 16px);
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--card-bg, #fff);
  color: var(--text);
  font-size: clamp(15px, 4vw, 16px);
  font-weight: 800;
  cursor: pointer;
  overflow: hidden;
  transition: all .25s;
}
#home-specials .big-btn::before {
  content: "";
  position: absolute;
  left: 0; top: 0;
  width: 4px; height: 100%;
  background: linear-gradient(180deg, var(--primary), var(--accent, #ff2bd6));
}
#home-specials .big-btn:hover {
  transform: translateX(4px);
  border-color: var(--primary);
}
#home-specials .big-btn.selected {
  border-color: var(--primary);
  background: var(--primary-light);
}
#home-specials .big-btn .icon {
  font-size: 32px;
  width: 52px;
  text-align: center;
  flex: 0 0 52px;
  background: rgba(0,0,0,.18);
  border-radius: 12px;
  padding: 6px 0;
  line-height: 1;
}
#home-specials .big-btn .stars {
  position: absolute;
  right: 12px;
  top: 8px;
  font-size: 12px;
  font-weight: 900;
  color: var(--primary);
  text-shadow: 0 0 6px rgba(255,215,0,.6);
  letter-spacing: 0.5px;
}
#home-specials .big-btn .txt {
  display: flex;
  flex-direction: column;
  line-height: 1.25;
}
#home-specials .big-btn .desc {
  font-size: 11px;
  font-weight: 500;
  color: var(--text-sub);
  margin-top: 3px;
  letter-spacing: 0.5px;
}

/* 树容器 */
.tree-box { margin-top: clamp(8px, 2.2vh, 12px); }

/* 系统两按钮横排 */
.sys-outer {
  display: flex;
  gap: 8px;
  margin-bottom: clamp(6px, 1.8vh, 10px);
}
.sys-btn-inline {
  flex: 1;
  padding: clamp(6px, 1.8vh, 8px) 10px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text);
  border-radius: 6px;
  font-size: clamp(12px, 3.2vw, 13px);
  font-weight: 700;
  cursor: pointer;
  transition: all .2s;
  text-align: center;
}
.sys-btn-inline:hover { border-color: var(--primary); }
.sys-btn-inline.selected {
  background: var(--primary-light);
  color: var(--primary);
  border-color: var(--primary);
}
.sys-desc-inline { font-size: 11px; opacity: .75; font-weight: 500; }

/* 学段 chip 一行（首页选择学段用；限定作用域，不影响阶段导航条 .stage-flow .stage-chip） */
.tree-stage {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: clamp(6px, 1.8vh, 10px);
}
.tree-stage .stage-chip {
  padding: clamp(5px, 1.6vh, 7px) clamp(10px, 3vw, 14px);
  border-radius: 6px;
  font-size: clamp(12px, 3.2vw, 13px);
  font-weight: 700;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text);
  cursor: pointer;
  transition: all .2s;
  letter-spacing: 1px;
}
.tree-stage .stage-chip:hover { border-color: var(--primary); }
.tree-stage .stage-chip.on {
  background: var(--primary-light);
  color: var(--primary);
  border-color: var(--primary);
}

/* 树 */
.tree { font-size: 14px; }
.tree-row {
  display: flex;
  align-items: center;
  padding: 10px 14px;
  border-left: 2px solid transparent;
  background: var(--card-bg, #fff);
  margin-bottom: 4px;
  font-weight: 600;
  cursor: pointer;
  transition: all .15s;
  border-radius: 4px;
}
.tree-row:hover {
  background: var(--primary-light);
  border-left-color: var(--primary);
}
.tree-row .arrow {
  margin-right: 8px;
  color: var(--text-sub);
  font-size: 12px;
  transition: transform .2s;
  width: 12px;
  text-align: center;
}
.tree-row.expanded .arrow { transform: rotate(90deg); }
.tree-row .t-label { flex: 1; }
.tree-row .t-count { font-size: 11px; color: var(--text-sub); }
.tree-children {
  padding-left: 18px;
  border-left: 1px dashed var(--border);
  margin-left: 8px;
}
.tree-node.selected > .tree-row {
  background: var(--primary);
  color: #fff;
  border-left-color: var(--primary);
}
.tree-node.selected > .tree-row .t-count { color: var(--text-sub); }
.tree-node.leaf > .tree-row { padding-left: 28px; }
.tree-node.leaf > .tree-row:hover { background: var(--primary-light); }

/* 开始按钮 */
#btn-start {
  margin-top: clamp(8px, 2.2vh, 12px);
  width: 100%;
  padding: clamp(10px, 2.8vh, 12px);
  font-size: 15px;
  font-weight: 700;
}

/* STAGE XP 进度条 */
.stage-bar-wrap {
  margin-top: clamp(12px, 3vh, 16px);
  padding: clamp(12px, 3vh, 16px);
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--card-bg, #fff);
}
.stage-bar-title {
  font-size: 12px;
  color: var(--primary);
  letter-spacing: 3px;
  margin-bottom: 10px;
  display: flex;
  justify-content: space-between;
  font-weight: 700;
}
.stage-bar-title .pct { color: var(--text); }
.stage-bar {
  height: 8px;
  background: var(--border);
  border-radius: 4px;
  position: relative;
  overflow: hidden;
}
.stage-bar-fill {
  position: absolute;
  left: 0; top: 0; height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--accent, #39ff88));
  box-shadow: 0 0 8px var(--primary);
  transition: width .4s;
}
.stage-labels {
  display: flex;
  justify-content: space-between;
  margin-top: 8px;
  font-size: 11px;
  color: var(--text-sub);
  letter-spacing: 1px;
}
.stage-labels span.done { color: var(--primary); font-weight: 700; }

/* 徽章行 */
.badges {
  display: flex;
  gap: 8px;
  margin-top: 12px;
  flex-wrap: wrap;
}
.badge {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), #f39c12);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  box-shadow: 0 4px 12px rgba(255,215,0,.4);
  font-weight: 900;
  color: #1a1a2e;
}
.badge.locked {
  background: #333;
  color: #666;
  box-shadow: none;
  font-size: 14px;
}
/* ============ 折叠树勾选选择器（home 浮层） ============ */
.kp-version { display:flex; gap:8px; padding:8px 16px; border-bottom:1px solid var(--border); }
.kp-vchip { padding:3px 12px; border-radius:12px; background:rgba(128,128,128,.15); cursor:pointer; font-size:13px; color:var(--text); }
.kp-vchip.on { background:var(--primary); color:#fff; }
.kp-tree { max-height:46vh; overflow-y:auto; padding:6px 12px; }
.kp-row { display:flex; align-items:center; gap:6px; padding:5px 6px; cursor:pointer; border-radius:6px; color:var(--text); }
.kp-row:hover { background:rgba(128,128,128,.12); }
.kp-l1 { padding-left:4px; font-weight:700; }
.kp-l2 { padding-left:26px; }
.kp-l3 { padding-left:48px; }
.kp-l4 { padding-left:70px; font-size:13px; color:var(--text-sub); }
.kp-row-name { flex:1; overflow:hidden; text-overflow:ellipsis; white-space:nowrap; }
.kp-row-arrow { width:18px; text-align:center; color:var(--text-sub); }
.kp-concepts { border-top:1px dashed var(--border); padding:8px 12px; max-height:30vh; overflow-y:auto; }
.kp-cp-title { font-size:12px; color:var(--text-sub); margin-bottom:6px; }
.kp-scope { border-top:1px solid var(--border); padding:10px 16px; font-size:13px; display:flex; align-items:center; gap:8px; flex-wrap:wrap; color:var(--text); }
.kp-scope-hint { color:var(--text-sub); font-size:12px; flex:1; }
.kp-plan-btn { margin-left:auto; padding:6px 14px; border:none; border-radius:8px; background:var(--primary); color:#fff; cursor:pointer; font-size:13px; }

/* ============ 新建学习计划（plan-create） ============ */
.pc-total { margin:10px 0 4px; font-size:14px; color:var(--text); }
.pc-scope { margin:10px 0 18px; display:flex; flex-direction:column; gap:10px; max-height:40vh; overflow-y:auto; }
.pc-group { border:1px solid var(--border); border-radius:10px; padding:10px 12px; background:rgba(128,128,128,.05); }
.pc-book { font-weight:700; font-size:14px; margin-bottom:6px; color:var(--primary); }
.pc-lessons { display:flex; flex-wrap:wrap; gap:6px; }
.pc-lesson { font-size:13px; padding:3px 10px; border-radius:12px; background:var(--primary-light); color:var(--primary); }
.pc-actions { display:flex; align-items:center; gap:16px; flex-wrap:wrap; margin-top:4px; }
.pc-days-label { font-size:14px; color:var(--text); }
.pc-days-label input { width:80px; padding:6px 8px; border:1px solid var(--border); border-radius:8px; font-size:15px; text-align:center; }

/* ============ 计划跟随页（plan-follow） ============ */
.pf-day { border:1px solid var(--border); border-radius:12px; margin-bottom:14px; overflow:hidden; }
.pf-day-title { padding:10px 14px; font-weight:700; background:rgba(128,128,128,.08); color:var(--text); }
.pf-lesson { padding:10px 14px; border-top:1px dashed var(--border); display:flex; align-items:center; gap:10px; cursor:pointer; color:var(--text); }
.pf-lesson:hover { background:rgba(128,128,128,.08); }
.pf-lesson.done { opacity:.55; }
.pf-lname { flex:1; font-size:15px; }
.pf-lmeta { font-size:12px; color:var(--text-sub); white-space:nowrap; }
.pf-manual { font-size:12px; padding:3px 10px; border:1px solid var(--border); border-radius:10px; background:transparent; color:var(--text-sub); cursor:pointer; }
.pf-concepts { padding:6px 14px 12px 28px; border-top:1px dashed var(--border); display:flex; flex-direction:column; gap:4px; }
.pf-concept { padding:7px 10px; border-radius:8px; background:rgba(128,128,128,.07); cursor:pointer; font-size:14px; color:var(--text); }
.pf-concept:hover { background:var(--primary-light); color:var(--primary); }
.pf-concept.done { opacity:.55; }
.pf-empty { padding:8px 2px; font-size:13px; color:var(--text-sub); }

/* ============ 选择器页签（直接学习 / 新建计划） ============ */
.kp-tabs { display:flex; gap:8px; padding:8px 16px; border-bottom:1px solid var(--border); }
.kp-tab { padding:5px 14px; border-radius:14px; background:rgba(128,128,128,.12); cursor:pointer; font-size:13px; color:var(--text); }
.kp-tab.on { background:var(--primary); color:#fff; }

/* ============ 直接学习页签：课时内知识点子列表 ============ */
.kp-lc { padding:4px 0 8px 24px; display:flex; flex-direction:column; gap:4px; }
.kp-lc-item { padding:7px 12px; border-radius:8px; background:rgba(128,128,128,.07); cursor:pointer; font-size:14px; color:var(--text); margin-left:22px; }
.kp-lc-item:hover { background:var(--primary-light); color:var(--primary); }
.kp-lc-item.empty { cursor:default; color:var(--text-sub); }

/* ============ 首页学习计划入口条 ============ */
.plan-entry-btn { width:100%; margin:8px 0 4px; padding:10px 14px; border:none; border-radius:10px;
  background:var(--primary-light); color:var(--primary); font-size:14px; font-weight:700; cursor:pointer; text-align:left; }
.plan-entry-btn:hover { filter:brightness(.96); }

/* ============ 计划页：多条计划切换条 / 名称栏 / 删除 ============ */
.pf-count { font-size:13px; color:var(--text-sub); font-weight:400; margin-left:6px; }
.pf-switch { display:flex; flex-wrap:wrap; gap:8px; padding:4px 0 10px; }
.pf-switch-item { padding:6px 14px; border-radius:16px; background:rgba(128,128,128,.12); cursor:pointer; font-size:13px; color:var(--text); }
.pf-switch-item.on { background:var(--primary); color:#fff; }
.pf-titlebar { display:flex; align-items:center; gap:10px; margin:2px 0 4px; }
.pf-title { font-size:17px; font-weight:700; color:var(--text); }
.pf-rename, .pf-del { font-size:12px; padding:4px 10px; border:1px solid var(--border); border-radius:10px; background:transparent; cursor:pointer; color:var(--text-sub); }
.pf-rename:hover { color:var(--primary); border-color:var(--primary); }
.pf-del:hover { color:var(--danger); border-color:var(--danger); }
.pf-name-input { font-size:16px; padding:4px 8px; border:1px solid var(--primary); border-radius:8px; width:260px; max-width:70%; }
.prog-plan { padding:10px 12px; border:1px solid var(--border); border-radius:10px; margin-bottom:8px; cursor:pointer; background:rgba(128,128,128,.06); }
.prog-plan.on { border-color:var(--primary); }
.prog-plan-name { font-weight:700; font-size:14px; color:var(--text); }
.prog-plan-meta { font-size:12px; color:var(--text-sub); margin:4px 0 6px; }
.prog-plan-bar { height:6px; border-radius:3px; background:rgba(128,128,128,.2); overflow:hidden; }
.prog-plan-fill { height:100%; border-radius:3px; background:var(--primary); }

/* ============ 草稿本（scratchpad） ============ */
.scratch-btn { position:fixed; right:18px; bottom:70px; z-index:999; display:flex; align-items:center; gap:6px;
  padding:10px 14px; border:none; border-radius:24px; background:var(--primary); color:#fff; font-size:14px;
  font-weight:700; cursor:pointer; box-shadow:0 4px 14px rgba(0,0,0,.25); }
.scratch-btn:hover { filter:brightness(1.08); }
.scratch-btn-txt { font-size:13px; }
.scratch-panel { position:fixed; right:18px; bottom:126px; z-index:1000; width:520px; height:400px;
  display:none; flex-direction:column; background:rgba(255,255,255,.38); border:1px solid rgba(0,0,0,.12);
  border-radius:14px; box-shadow:0 10px 30px rgba(0,0,0,.25); overflow:hidden; }
.scratch-head { display:flex; align-items:center; gap:6px; padding:8px 10px; background:rgba(255,255,255,.45);
  cursor:grab; user-select:none; -webkit-user-select:none; flex:0 0 auto; }
.scratch-title { font-size:13px; font-weight:700; color:#1f2937; margin-right:auto; }
.scratch-tool, .scratch-close { border:1px solid rgba(0,0,0,.18); background:rgba(255,255,255,.85); color:#1f2937;
  border-radius:8px; padding:4px 10px; font-size:13px; cursor:pointer; }
.scratch-tool.on { background:#f59e0b; color:#fff; border-color:#f59e0b; }
.scratch-tool:hover, .scratch-close:hover { background:#e2e8f0; }
/* 竖向粗细/大小调节弹层（点画笔/橡皮图标时在图标下方出现） */
.scratch-size-pop {
  position:absolute; z-index:10; flex-direction:column; align-items:center; gap:6px;
  padding:8px 10px; background:rgba(255,255,255,.92); border:1px solid rgba(0,0,0,.16);
  border-radius:12px; box-shadow:0 6px 18px rgba(0,0,0,.18);
}
.scratch-size-label { font-size:12px; font-weight:700; color:#1f2937; }
.scratch-size-range-v {
  writing-mode: vertical-lr; direction: rtl;
  -webkit-appearance: slider-vertical;
  width: 26px; height: 130px; cursor: pointer;
}
.scratch-size-val { font-size:12px; font-weight:700; color:var(--primary); }
.scratch-close { border-radius:50%; }
.scratch-body { flex:1; padding:7px; overflow:hidden; }
.scratch-body canvas { width:100%; height:100%; display:block; border-radius:8px; cursor:crosshair;
  background:transparent; touch-action:none; }
.scratch-resize { position:absolute; right:0; bottom:0; width:22px; height:22px; cursor:nwse-resize;
  background:linear-gradient(135deg, transparent 50%, rgba(0,0,0,.35) 50%); border-bottom-right-radius:14px; }

.stage-chip.done, .stage-chip.current { cursor: pointer; }
.stage-chip.done:hover, .stage-chip.current:hover { filter: brightness(1.06); transition: filter .15s; }
/* ============ 前置知识检测题 ============ */
.plan-block { margin: 14px 0; }
.plan-block h4 { margin: 10px 0 8px; font-size: 15px; }
.plan-muted { font-size: 13px; color: var(--text-sub); line-height: 1.7; }
.plan-list { padding-left: 20px; margin: 6px 0; font-size: 14px; line-height: 1.8; }
.tag-lv { display: inline-block; font-size: 11px; padding: 1px 6px; border-radius: 8px; background: var(--primary-light); color: var(--primary); margin-left: 6px; vertical-align: 1px; }
.prereq-item { border: 1px solid var(--border); border-radius: 10px; padding: 12px 14px; margin: 10px 0; }
.prereq-q { font-size: 14px; margin-bottom: 6px; }
.prereq-ques { font-size: 14px; color: var(--text-main); line-height: 1.7; margin-bottom: 8px; }
.prereq-input { width: 100%; box-sizing: border-box; padding: 8px 10px; border: 1px solid var(--border); border-radius: 8px; font-size: 14px; }
.prereq-input:disabled { background: var(--bg-sub); color: var(--text-sub); }
.prereq-pass { color: var(--success, #16a34a); font-size: 13px; margin-left: 8px; }
.prereq-fail { color: var(--warn, #d97706); font-size: 13px; margin-left: 8px; }
.prereq-hint { font-size: 13px; color: #92400e; background: var(--warn-bg); border: 1px solid #fde68a; border-radius: 8px; padding: 8px 10px; margin-top: 8px; line-height: 1.6; }
.prereq-done-banner { border: 1px solid var(--success); background: var(--success-bg); border-radius: 10px; padding: 10px 14px; margin-top: 10px; color: var(--success-text, #166534); font-size: 14px; }
/* ============ 学习模式选择（创建计划/计划页） ============ */
.pc-sys, .pf-sys { display:flex; align-items:center; gap:8px; margin:12px 0; flex-wrap:wrap; }
.pc-sys-label, .pf-sys-label { font-size:14px; font-weight:700; color:var(--text); }
.pc-sys-btn, .pf-sys-btn {
  border:1px solid var(--border); background:var(--card-bg,#fff); color:var(--text);
  border-radius:10px; padding:6px 12px; font-size:14px; cursor:pointer;
}
.pc-sys-btn.on, .pf-sys-btn.on {
  border-color:var(--primary); background:var(--primary); color:#fff; font-weight:700;
}
.pf-sys-hint { font-size:12px; color:var(--text-sub); width:100%; }