/* ════════════════════════════════════════════════════════════
   在线学习与考试系统 - 统一设计系统 v6
   风格：互联网大厂C端（字节/腾讯/阿里系）
   原则：简洁 · 清晰 · 有温度 · 跨端兼容
   ════════════════════════════════════════════════════════════ */

/* ── 基础重置与变量 ── */
:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --primary-ghost: rgba(37,99,235,0.08);

  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --info: #06b6d4;

  --text-main: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --text-ghost: #cbd5e1;

  --bg-page: #f8fafc;
  --bg-card: #ffffff;
  --bg-hover: #f1f5f9;
  --bg-ghost: #f8fafc;

  --border-color: #e2e8f0;
  --border-light: #f1f5f9;

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-pill: 100px;

  --shadow-xs: 0 1px 2px rgba(15,23,42,0.04);
  --shadow-sm: 0 1px 3px rgba(15,23,42,0.06), 0 1px 2px rgba(15,23,42,0.04);
  --shadow-md: 0 4px 12px rgba(15,23,42,0.08);
  --shadow-lg: 0 10px 32px rgba(15,23,42,0.12);
  --shadow-xl: 0 20px 48px rgba(15,23,42,0.16);

  --transition-fast: all 0.15s cubic-bezier(0.4,0,0.2,1);
  --transition-base: all 0.25s cubic-bezier(0.4,0,0.2,1);
  --transition-slow: all 0.4s cubic-bezier(0.4,0,0.2,1);

  --font-sans: -apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,'Helvetica Neue',Arial,'Noto Sans SC',sans-serif;
  --font-mono: 'SFMono-Regular',Consolas,'Liberation Mono',Menlo,Courier,monospace;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--text-main);
  background: var(--bg-page);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ═══════════════════════════════════════════
   导航栏
   ═══════════════════════════════════════════ */
.app-nav {
  position: sticky; top: 0; z-index: 1030;
  background: rgba(255,255,255,0.92);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border-light);
}
.app-nav-inner {
  max-width: 1280px; margin: 0 auto;
  display: flex; align-items: center;
  padding: 0 24px; height: 56px; gap: 16px;
}
.app-nav-brand {
  font-weight: 700; font-size: 1.125rem; color: var(--text-main);
  text-decoration: none; display: flex; align-items: center; gap: 8px;
  flex-shrink: 0;
}
.app-nav-brand .brand-icon {
  width: 30px; height: 30px;
  background: linear-gradient(135deg,var(--primary) 0%, #60a5fa 100%);
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-size: 14px;
}
.app-nav-links {
  display: flex; align-items: center; gap: 2px;
  flex: 1; min-width: 0; /* 兜底：允许收缩，防止挤压右侧用户区 */
}
.app-nav-links a {
  padding: 6px 12px; border-radius: var(--radius-sm);
  color: var(--text-secondary); font-size: 0.875rem;
  font-weight: 500; text-decoration: none; white-space: nowrap;
  transition: var(--transition-fast);
}
.app-nav-links a:hover { color: var(--primary); background: var(--primary-ghost); }
.app-nav-links a.active { color: var(--primary); background: var(--primary-light); }
.app-nav-user {
  display: flex; align-items: center; gap: 12px;
  flex-shrink: 0;
}
.app-nav-user .user-name {
  font-size: 0.875rem; font-weight: 500; color: var(--text-secondary);
}
.app-nav-toggle {
  display: none; border: none; background: transparent;
  padding: 4px; cursor: pointer; color: var(--text-secondary);
}
/* <1100px：横向导航（5链接+管理后台/平台运营下拉+用户区）合计约需1100px，
   空间不足会挤压右侧铃铛/用户区，故此区间导航链接统一收纳为抽屉（复用移动端逻辑） */
@media (max-width: 1099.98px) {
  .app-nav-links { display: none; position: absolute; top: 56px; left: 0; right: 0;
    background: rgba(255,255,255,0.98); backdrop-filter: blur(12px);
    flex-direction: column; padding: 8px 16px 16px;
    border-bottom: 1px solid var(--border-light); gap: 4px;
  }
  .app-nav-links.open { display: flex; }
  .app-nav-links a { width: 100%; padding: 10px 12px; }
  .app-nav-toggle { display: block; margin-left: auto; }
}
@media (max-width: 767.98px) {
  .app-nav-inner { padding: 0 16px; }
  .app-nav-user .user-name { display: none; }
}

/* ═══════════════════════════════════════════
   页面布局
   ═══════════════════════════════════════════ */
.app-page { min-height: 100vh; display: flex; flex-direction: column; }
.app-main { max-width: 1280px; margin: 0 auto; width: 100%; padding: 24px; flex: 1; }
@media (max-width: 767.98px) { .app-main { padding: 16px; } }

/* ── 教练/特殊页面的居中容器 ── */
.app-container { max-width: 960px; margin: 0 auto; width: 100%; padding: 24px; }
.app-container-sm { max-width: 720px; margin: 0 auto; width: 100%; padding: 24px; }
@media (max-width: 767.98px) { .app-container, .app-container-sm { padding: 16px; } }

/* ═══════════════════════════════════════════
   页面标题区
   ═══════════════════════════════════════════ */
.page-header { margin-bottom: 24px; }
.page-header-row { display: flex; align-items: flex-start; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.page-title { font-size: 1.5rem; font-weight: 700; color: var(--text-main); margin: 0 0 4px; letter-spacing: -0.01em; }
.page-title-sub { font-size: 0.875rem; color: var(--text-muted); margin: 0; }
@media (max-width: 767.98px) { .page-title { font-size: 1.25rem; } }

/* ── 分区标题 ── */
.section-title {
  font-size: 1.15rem; font-weight: 700; color: var(--text-main);
  margin: 0 0 4px; letter-spacing: -0.01em;
}
.section-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 16px; gap: 12px; flex-wrap: wrap;
}
.section-header h3 { font-size: 1.1rem; font-weight: 700; margin: 0; }

/* ═══════════════════════════════════════════
   Hero 区域
   ═══════════════════════════════════════════ */
.hero-section {
  background: linear-gradient(135deg, #2563eb 0%, #7c3aed 50%, #06b6d4 100%);
  background-size: 200% 200%; animation: heroGrad 12s ease infinite;
  color: #fff; border-radius: var(--radius-lg);
  padding: 40px; margin-bottom: 32px; position: relative; overflow: hidden;
}
.hero-section::before {
  content: ''; position: absolute; top: -50%; right: -20%;
  width: 400px; height: 400px; border-radius: 50%;
  background: rgba(255,255,255,0.08);
  pointer-events: none;
}
.hero-section h2 { font-size: 1.75rem; font-weight: 700; margin-bottom: 8px; position: relative; }
.hero-section p { opacity: 0.85; font-size: 1rem; margin: 0; position: relative; }
@keyframes heroGrad {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}
@media (max-width: 767.98px) { .hero-section { padding: 24px; } .hero-section h2 { font-size: 1.375rem; } }

/* ═══════════════════════════════════════════
   卡片系统
   ═══════════════════════════════════════════ */
.card-app {
  background: var(--bg-card); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm); border: 1px solid var(--border-light);
  transition: var(--transition-base); overflow: hidden;
}
.card-app:hover { box-shadow: var(--shadow-md); }
.card-app .card-header {
  padding: 20px 24px; border-bottom: 1px solid var(--border-light);
  display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap;
}
.card-app .card-header-title { font-size: 1rem; font-weight: 600; color: var(--text-main); margin: 0; }
.card-app .card-body { padding: 24px; }
@media (max-width: 767.98px) {
  .card-app .card-header { padding: 16px 20px; }
  .card-app .card-body { padding: 16px 20px; }
}

/* ── 功能入口卡片 ── */
.feature-card {
  background: var(--bg-card); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm); border: 1px solid var(--border-light);
  cursor: pointer; transition: var(--transition-base);
  overflow: hidden; height: 100%; text-decoration: none; display: block;
}
.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-light);
}
.feature-card:active { transform: translateY(-2px); }
.feature-card .card-body { padding: 28px 24px; text-align: center; }
.feature-icon {
  width: 56px; height: 56px; border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 16px;
}
.feature-icon svg { width: 28px; height: 28px; }
.feature-card .card-title { font-size: 1.0625rem; font-weight: 600; color: var(--text-main); margin-bottom: 6px; }
.feature-card .card-text { font-size: 0.875rem; color: var(--text-muted); margin: 0; }

/* ── 课程卡片 ── */
.course-card {
  background: var(--bg-card); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm); border: 1px solid var(--border-light);
  cursor: pointer; transition: var(--transition-base);
  overflow: hidden; height: 100%;
}
.course-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}
.course-card .card-img-top {
  height: 180px; background: var(--bg-ghost);
  display: flex; align-items: center; justify-content: center;
  overflow: hidden;
}
.course-card .card-img-top img { width: 100%; height: 100%; object-fit: cover; }
.course-card .card-body { padding: 20px; }
.course-card .badge { font-size: 0.75rem; padding: 5px 10px; border-radius: var(--radius-sm); font-weight: 500; }
.course-card .card-title { font-size: 1rem; font-weight: 600; color: var(--text-main); margin: 8px 0 6px; }
.course-card .card-text { font-size: 0.875rem; color: var(--text-muted); margin: 0 0 8px; }
@media (max-width: 767.98px) { .course-card .card-img-top { height: 150px; } }

/* ── 考试卡片 ── */
.exam-card {
  background: var(--bg-card); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm); border: 1px solid var(--border-light);
  transition: var(--transition-base); overflow: hidden; height: 100%;
}
.exam-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.exam-card .card-body { padding: 20px 24px; }
.exam-card .badge { font-size: 0.75rem; padding: 5px 10px; border-radius: var(--radius-sm); }
.exam-card .card-footer { background: transparent; border-top: 1px solid var(--border-light); padding: 14px 24px; }

/* ── 任务卡片（左侧颜色条） ── */
.task-card {
  background: #fff; border-radius: var(--radius-lg); border: 1px solid var(--border-color);
  padding: 20px; cursor: pointer; transition: var(--transition-base); position: relative; overflow: hidden;
}
.task-card::before { content:''; position:absolute; left:0; top:0; bottom:0; width:4px; background:var(--border-color); }
.task-card.completed::before { background: var(--success); }
.task-card.in-progress::before { background: var(--primary); }
.task-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }

/* ═══════════════════════════════════════════
   表格
   ═══════════════════════════════════════════ */
.table-app { width: 100%; border-collapse: separate; border-spacing: 0; }
.table-app thead th {
  background: var(--bg-ghost); font-weight: 600; color: var(--text-secondary);
  border-bottom: 2px solid var(--border-color);
  padding: 12px 16px; font-size: 0.8125rem; text-align: left;
  white-space: nowrap;
}
.table-app tbody td {
  padding: 12px 16px; font-size: 0.875rem;
  color: var(--text-main); border-bottom: 1px solid var(--border-light);
  vertical-align: middle;
}
.table-app tbody tr:hover td { background: var(--bg-hover); }
.table-app tbody tr:last-child td { border-bottom: none; }
@media (max-width: 767.98px) {
  .table-app thead th, .table-app tbody td { padding: 10px 12px; font-size: 0.8125rem; }
}

/* ── Bootstrap 表格统一覆写 ── */
.table-wrap {
  background: var(--bg-card); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm); border: 1px solid var(--border-light); overflow: hidden;
}
.table-wrap table { margin: 0; }
.table-wrap thead th {
  background: var(--bg-ghost); font-weight: 600; font-size: 0.8rem;
  color: var(--text-secondary); padding: 12px 16px; border-bottom: 2px solid var(--border-color);
}
.table-wrap tbody td {
  padding: 12px 16px; font-size: 0.875rem; vertical-align: middle;
  border-bottom: 1px solid var(--border-light);
}
.table-wrap tbody tr:hover { background: var(--bg-hover); }
.table-wrap tbody tr:last-child td { border-bottom: none; }

/* ── 树形表格 ── */
.tree-table { width: 100%; border-collapse: collapse; }
.tree-table thead th { background: var(--bg-ghost); font-weight: 600; color: var(--text-secondary);
  border-bottom: 2px solid var(--border-color); padding: 12px 16px; font-size: 0.8125rem; text-align: left; }
.tree-table tbody td { padding: 12px 16px; font-size: 0.875rem; color: var(--text-main); border-bottom: 1px solid var(--border-light); vertical-align: middle; }
.tree-table tbody tr:hover { background: var(--bg-hover); }
.tree-toggle { cursor: pointer; display: inline-flex; align-items: center; justify-content: center;
  width: 20px; height: 20px; margin-right: 6px; border-radius: 4px; color: var(--text-muted); transition: transform 0.2s; }
.tree-toggle:hover { background: var(--border-light); }
.tree-toggle.collapsed svg { transform: rotate(-90deg); }
.tree-toggle.leaf { visibility: hidden; pointer-events: none; }
.tree-indent { display: inline-block; width: 26px; }
.tree-name { font-weight: 500; color: var(--text-main); }

/* ═══════════════════════════════════════════
   表单
   ═══════════════════════════════════════════ */
.form-control-app, .form-select-app {
  border: 1px solid var(--border-color); border-radius: var(--radius-md);
  padding: 9px 14px; font-size: 0.875rem; color: var(--text-main);
  background: var(--bg-card); transition: var(--transition-fast);
  width: 100%;
}
.form-control-app:focus, .form-select-app:focus {
  border-color: var(--primary); outline: none;
  box-shadow: 0 0 0 3px rgba(37,99,235,0.12);
}
.form-label-app {
  font-weight: 500; font-size: 0.8125rem; color: var(--text-secondary);
  margin-bottom: 6px; display: block;
}

/* ═══════════════════════════════════════════
   按钮系统 v6
   设计原则：hover 微浮起 + 阴影 → active 按下反馈 → disabled 置灰
   尺寸：默认/sm/lg  变体：primary/success/warning/danger/outline/ghost/link
   ═══════════════════════════════════════════ */
.btn-app {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  padding: 8px 18px; border-radius: 10px;
  font-size: 0.875rem; font-weight: 500; line-height: 1.5;
  border: 1px solid transparent; cursor: pointer;
  text-decoration: none; white-space: nowrap;
  font-family: inherit; user-select: none;
  transition: all 0.18s cubic-bezier(0.4,0,0.2,1);
  position: relative; -webkit-tap-highlight-color: transparent;
}

/* ── 尺寸变体 ── */
.btn-app-sm { padding: 5px 12px; font-size: 0.8125rem; border-radius: var(--radius-sm); }
.btn-app-lg { padding: 12px 26px; font-size: 0.9375rem; border-radius: var(--radius-md); }

/* =================== 实心按钮 =================== */

/* ── Primary 蓝色主操作 ── */
.btn-app-primary {
  background: var(--primary); color: #fff; border-color: var(--primary);
  box-shadow: 0 1px 3px rgba(37,99,235,0.25);
}
.btn-app-primary:hover {
  background: var(--primary-hover); border-color: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(37,99,235,0.32);
}
.btn-app-primary:active { transform: translateY(0); box-shadow: 0 1px 2px rgba(37,99,235,0.18); }
.btn-app-primary:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }
.btn-app-primary:disabled { background: #cbd5e1; color: #94a3b8; border-color: #cbd5e1; box-shadow: none; cursor: not-allowed; transform: none; }

/* ── Success 绿色（发布/通过） ── */
.btn-app-success {
  background: var(--success); color: #fff; border-color: var(--success);
  box-shadow: 0 1px 3px rgba(16,185,129,0.25);
}
.btn-app-success:hover {
  background: #059669; border-color: #059669;
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(16,185,129,0.32);
}
.btn-app-success:active { transform: translateY(0); box-shadow: 0 1px 2px rgba(16,185,129,0.18); }
.btn-app-success:focus-visible { outline: 2px solid var(--success); outline-offset: 2px; }
.btn-app-success:disabled { background: #cbd5e1; color: #94a3b8; border-color: #cbd5e1; box-shadow: none; cursor: not-allowed; transform: none; }

/* ── Warning 琥珀色 ── */
.btn-app-warning {
  background: var(--warning); color: #fff; border-color: var(--warning);
  box-shadow: 0 1px 3px rgba(245,158,11,0.25);
}
.btn-app-warning:hover {
  background: #d97706; border-color: #d97706;
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(245,158,11,0.32);
}
.btn-app-warning:active { transform: translateY(0); box-shadow: 0 1px 2px rgba(245,158,11,0.18); }
.btn-app-warning:focus-visible { outline: 2px solid var(--warning); outline-offset: 2px; }
.btn-app-warning:disabled { background: #cbd5e1; color: #94a3b8; border-color: #cbd5e1; box-shadow: none; cursor: not-allowed; transform: none; }

/* ── Danger 红色（删除/危险） ── */
.btn-app-danger {
  background: var(--danger); color: #fff; border-color: var(--danger);
  box-shadow: 0 1px 3px rgba(239,68,68,0.25);
}
.btn-app-danger:hover {
  background: #dc2626; border-color: #dc2626;
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(239,68,68,0.32);
}
.btn-app-danger:active { transform: translateY(0); box-shadow: 0 1px 2px rgba(239,68,68,0.18); }
.btn-app-danger:focus-visible { outline: 2px solid var(--danger); outline-offset: 2px; }
.btn-app-danger:disabled { background: #cbd5e1; color: #94a3b8; border-color: #cbd5e1; box-shadow: none; cursor: not-allowed; transform: none; }

/* =================== 线框按钮 =================== */

/* ── Outline 中性边框（次要操作/编辑/预览） ── */
.btn-app-outline {
  background: var(--bg-card); color: var(--text-secondary);
  border-color: var(--border-color);
  box-shadow: var(--shadow-xs);
}
.btn-app-outline:hover {
  border-color: var(--primary); color: var(--primary);
  background: var(--primary-ghost);
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(37,99,235,0.12);
}
.btn-app-outline:active { transform: translateY(0); }
.btn-app-outline:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }
.btn-app-outline:disabled { color: #cbd5e1; border-color: #e2e8f0; background: #f8fafc; box-shadow: none; cursor: not-allowed; transform: none; }

/* ── Ghost 极淡透明（表格行内操作/标签） ── */
.btn-app-ghost {
  background: transparent; color: var(--text-secondary);
  border-color: transparent;
}
.btn-app-ghost:hover {
  background: var(--primary-ghost); color: var(--primary);
}
.btn-app-ghost:active { background: rgba(37,99,235,0.14); }
.btn-app-ghost:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }
.btn-app-ghost:disabled { color: #cbd5e1; cursor: not-allowed; }

/* ── Link 文字链接型按钮（清空/重置等辅助操作） ── */
.btn-app-link {
  background: transparent; color: var(--primary); border-color: transparent;
  padding-left: 4px; padding-right: 4px; text-decoration: none;
}
.btn-app-link:hover { color: var(--primary-hover); text-decoration: underline; background: transparent; }
.btn-app-link:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; border-radius: 4px; }
.btn-app-link:disabled { color: #cbd5e1; cursor: not-allowed; text-decoration: none; }

/* =================== 宽度工具 =================== */
.btn-app-block { display: flex; width: 100%; }

/* ── 返回按钮 ── */
.btn-back {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 7px 14px; border-radius: var(--radius-md);
  font-size: 0.875rem; font-weight: 500; color: var(--text-secondary);
  background: var(--bg-card); border: 1px solid var(--border-color);
  text-decoration: none; transition: var(--transition-fast);
}
.btn-back:hover { border-color: var(--primary); color: var(--primary); background: var(--primary-ghost); }

/* ═══════════════════════════════════════════
   标签
   ═══════════════════════════════════════════ */
.tag-app {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 5px 12px; border-radius: var(--radius-pill);
  font-size: 0.8125rem; font-weight: 500; cursor: pointer;
  transition: var(--transition-fast); user-select: none;
  border: 1px solid var(--border-color); background: var(--bg-card); color: var(--text-secondary);
}
.tag-app:hover { border-color: var(--primary); color: var(--primary); background: var(--primary-ghost); }
.tag-app.active { background: var(--primary); color: #fff; border-color: var(--primary); }
.tag-app .tag-check { display: none; width: 14px; height: 14px; }
.tag-app.active .tag-check { display: inline-block; }

/* ── 状态标签 ── */
.status-tag {
  display: inline-flex; align-items: center; gap: 4px;
  font-size: 0.72rem; font-weight: 600; padding: 3px 10px; border-radius: var(--radius-pill);
}
.status-tag.pending { background: #fef3c7; color: #92400e; }
.status-tag.done { background: #dcfce7; color: #16a34a; }
.status-tag.draft { background: #f1f5f9; color: #64748b; }
.status-tag.published { background: #dbeafe; color: #1e40af; }
.status-tag.primary { background: var(--primary-light); color: var(--primary); }
.status-tag.success { background: #dcfce7; color: #16a34a; }
.status-tag.danger { background: #fef2f2; color: #ef4444; }

/* ═══════════════════════════════════════════
   搜索栏
   ═══════════════════════════════════════════ */
.search-bar {
  background: var(--bg-card); border-radius: var(--radius-lg);
  padding: 20px 24px; box-shadow: var(--shadow-sm); border: 1px solid var(--border-light);
  margin-bottom: 24px;
}
@media (max-width: 767.98px) { .search-bar { padding: 16px; } }

/* ═══════════════════════════════════════════
   模态框
   ═══════════════════════════════════════════ */
.modal-content { border-radius: var(--radius-lg) !important; border: none !important; box-shadow: var(--shadow-xl) !important; }
.modal-header { border-bottom: 1px solid var(--border-light) !important; padding: 20px 24px !important; }
.modal-header .modal-title { font-weight: 600; font-size: 1.0625rem; }
.modal-body { padding: 24px !important; }
.modal-footer { border-top: 1px solid var(--border-light) !important; padding: 16px 24px !important; }
@media (max-width: 767.98px) {
  .modal-header { padding: 16px 20px !important; }
  .modal-body { padding: 16px 20px !important; }
  .modal-footer { padding: 12px 20px !important; }
}

/* ═══════════════════════════════════════════
   加载状态
   ═══════════════════════════════════════════ */
/* 居中 Spinner */
.loading-center {
  display: flex; align-items: center; justify-content: center;
  padding: 64px 24px; color: var(--text-muted);
}
.loading-center .spinner-border { width: 2rem; height: 2rem; }

/* 骨架屏 */
.skeleton {
  background: linear-gradient(90deg, #f1f5f9 25%, #e2e8f0 50%, #f1f5f9 75%);
  background-size: 200% 100%; animation: skeleton 1.2s infinite;
  border-radius: 8px;
}
@keyframes skeleton { 0% { background-position: 200% 0; } 100% { background-position: -200% 0; } }
.skeleton-text { height: 16px; margin-bottom: 10px; width: 100%; }
.skeleton-text.short { width: 60%; }
.skeleton-title { height: 24px; margin-bottom: 16px; width: 80%; }
.skeleton-img { height: 180px; width: 100%; border-radius: var(--radius-lg) var(--radius-lg) 0 0; }

/* ═══════════════════════════════════════════
   空状态
   ═══════════════════════════════════════════ */
.empty-state { text-align: center; padding: 64px 24px; }
.empty-state svg { width: 64px; height: 64px; color: var(--text-ghost); margin-bottom: 16px; }
.empty-state h4 { font-size: 1rem; font-weight: 600; color: var(--text-secondary); margin: 0 0 6px; }
.empty-state p { font-size: 0.85rem; color: var(--text-muted); margin: 0; }
.empty-state.compact { padding: 40px 24px; }
.empty-state.compact svg { width: 48px; height: 48px; }

/* ═══════════════════════════════════════════
   统计卡片
   ═══════════════════════════════════════════ */
.stat-card {
  background: var(--bg-card); border-radius: var(--radius-lg);
  padding: 24px; text-align: center; box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
}
.stat-value { font-size: 2rem; font-weight: 700; color: var(--text-main); }
.stat-label { font-size: 0.875rem; color: var(--text-muted); margin-top: 4px; }
.stat-card.primary { border-top: 3px solid var(--primary); }
.stat-card.success { border-top: 3px solid var(--success); }
.stat-card.warning { border-top: 3px solid var(--warning); }
.stat-card.info { border-top: 3px solid var(--info); }

/* 统计图标卡片 */
.stat-icon-card {
  background: var(--bg-card); border-radius: var(--radius-lg);
  padding: 20px; box-shadow: var(--shadow-sm); border: 1px solid var(--border-light);
  transition: var(--transition-base); display: flex; align-items: center; gap: 16px;
}
.stat-icon-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }
.stat-icon-card .stat-icon {
  width: 48px; height: 48px; border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center; flex-shrink: 0;
}
.stat-icon-card .stat-icon svg { width: 24px; height: 24px; }
.stat-icon-card .stat-num { font-size: 1.75rem; font-weight: 800; line-height: 1; }
.stat-icon-card .stat-text { font-size: 0.82rem; color: var(--text-muted); }

/* ═══════════════════════════════════════════
   进度条
   ═══════════════════════════════════════════ */
.progress-app { height: 6px; background: var(--border-light); border-radius: var(--radius-pill); overflow: hidden; }
.progress-app-bar { height: 100%; border-radius: var(--radius-pill); transition: width 0.6s cubic-bezier(0.4,0,0.2,1); }
.progress-app-bar.primary { background: var(--primary); }
.progress-app-bar.success { background: var(--success); }
.progress-app-bar.warning { background: var(--warning); }

/* 大号进度条（培训详情用） */
.progress-lg { height: 10px; background: #e2e8f0; border-radius: var(--radius-pill); overflow: hidden; }
.progress-lg-bar { height: 100%; border-radius: var(--radius-pill); transition: width 0.6s cubic-bezier(0.4,0,0.2,1); }

/* ═══════════════════════════════════════════
   题目卡片
   ═══════════════════════════════════════════ */
.question-card {
  background: var(--bg-card); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm); border: 1px solid var(--border-light);
  margin-bottom: 20px; overflow: hidden;
}
.question-card .card-header {
  background: var(--bg-ghost); border-bottom: 1px solid var(--border-light);
  padding: 16px 20px;
}
.question-card .card-body { padding: 20px; }

/* ── 选项 ── */
.option-item {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 14px; border-radius: var(--radius-md);
  border: 1px solid var(--border-light); margin-bottom: 8px;
  cursor: pointer; transition: var(--transition-fast);
  background: var(--bg-card);
}
.option-item:hover { border-color: var(--primary); background: var(--primary-light); }
.option-item.selected { border-color: var(--primary); background: var(--primary-light); }
.option-item .option-key {
  width: 24px; height: 24px; border-radius: 50%;
  border: 2px solid var(--border-color); display: flex;
  align-items: center; justify-content: center;
  font-size: 0.75rem; font-weight: 600; color: var(--text-muted);
  flex-shrink: 0; transition: var(--transition-fast);
}
.option-item.selected .option-key { background: var(--primary); border-color: var(--primary); color: #fff; }

/* ═══════════════════════════════════════════
   Tab 切换
   ═══════════════════════════════════════════ */
.tab-bar {
  display: flex; gap: 4px; background: #f1f5f9; border-radius: 8px; padding: 3px;
}
.tab-btn {
  padding: 7px 16px; border-radius: 7px; font-size: 0.82rem; font-weight: 500;
  cursor: pointer; border: none; background: transparent; color: #64748b;
  transition: var(--transition-fast); font-family: inherit;
}
.tab-btn:hover { color: var(--text-main); }
.tab-btn.active { background: #fff; color: #1e293b; box-shadow: 0 1px 2px rgba(0,0,0,0.06); }

/* ── 下划线 Tab ── */
.tab-underline {
  display: flex; gap: 0; border-bottom: 2px solid var(--border-light);
}
.tab-underline .tab-link {
  padding: 10px 20px; font-size: 0.875rem; font-weight: 500; color: var(--text-muted);
  background: none; border: none; border-bottom: 2px solid transparent;
  margin-bottom: -2px; cursor: pointer; transition: var(--transition-fast);
  font-family: inherit;
}
.tab-underline .tab-link:hover { color: var(--text-main); }
.tab-underline .tab-link.active { color: var(--primary); border-bottom-color: var(--primary); }
.tab-underline .tab-link .tab-count { font-size: 0.75rem; margin-left: 4px; opacity: 0.7; }

/* ═══════════════════════════════════════════
   排行榜
   ═══════════════════════════════════════════ */
.lb-card {
  background: var(--bg-card); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm); border: 1px solid var(--border-light); overflow: hidden;
}
.lb-card .lb-header { padding: 16px 20px; background: var(--bg-ghost); border-bottom: 1px solid var(--border-light);
  display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px;
}
.lb-card .lb-header h3 { font-size: 1rem; font-weight: 700; margin: 0; }
.lb-list { padding: 8px 16px 16px; }
.lb-item { display: flex; align-items: center; padding: 10px 12px; border-radius: 10px; margin-bottom: 2px; transition: background 0.15s; }
.lb-item:hover { background: var(--bg-hover); }
.lb-item.me { background: var(--primary-light); border: 1px solid #bfdbfe; }
.lb-rank { width: 36px; font-weight: 700; text-align: center; font-size: 0.9rem; }
.lb-rank.top1 { color: #f59e0b; font-size: 1.25rem; }
.lb-rank.top2 { color: #94a3b8; font-size: 1.15rem; }
.lb-rank.top3 { color: #d97706; font-size: 1.05rem; }
.lb-avatar {
  width: 34px; height: 34px; border-radius: 50%;
  background: linear-gradient(135deg,#667eea,#764ba2); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-weight: 600; font-size: 0.8rem; margin: 0 10px; flex-shrink: 0;
}
.lb-name { flex: 1; font-weight: 500; font-size: 0.88rem; }
.lb-score { font-weight: 700; font-size: 0.92rem; text-align: right; min-width: 50px; }
.lb-unit { font-size: 0.75rem; color: var(--text-muted); margin-left: 2px; }
.lb-empty { text-align: center; padding: 40px 24px; color: var(--text-muted); }

/* ═══════════════════════════════════════════
   计时器
   ═══════════════════════════════════════════ */
.timer-box {
  background: #fffbeb; border: 1px solid #fde68a; border-radius: var(--radius-md);
  padding: 8px 16px; font-weight: 600; color: #92400e; font-size: 0.875rem;
}
.timer-box.danger { background: #fef2f2; border-color: #fecaca; color: #991b1b; }

/* ═══════════════════════════════════════════
   通知 / Toast
   ═══════════════════════════════════════════ */
.toast-app {
  position: fixed; top: 80px; right: 24px; z-index: 9999;
  padding: 14px 20px; border-radius: var(--radius-md); font-size: 0.875rem;
  box-shadow: var(--shadow-lg); max-width: 360px; animation: toastIn 0.3s ease;
  display: flex; align-items: center; gap: 10px;
}
.toast-app.success { background: #dcfce7; color: #166534; border: 1px solid #bbf7d0; }
.toast-app.error { background: #fef2f2; color: #991b1b; border: 1px solid #fecaca; }
.toast-app.info { background: var(--primary-light); color: #1e40af; border: 1px solid #bfdbfe; }
@keyframes toastIn { from { opacity: 0; transform: translateX(40px); } to { opacity: 1; transform: translateX(0); } }

/* ═══════════════════════════════════════════
   响应式网格（替代 Bootstrap row/col）
   ═══════════════════════════════════════════ */
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
@media (max-width: 1199.98px) { .grid-4 { grid-template-columns: repeat(3, 1fr); } }
@media (max-width: 991.98px)  { .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 575.98px)  { .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; gap: 14px; } }

/* ═══════════════════════════════════════════
   步骤引导（培训详情用）
   ═══════════════════════════════════════════ */
.step-list { display: flex; flex-direction: column; gap: 12px; }
.step-item {
  display: flex; align-items: center; gap: 14px; padding: 12px 16px;
  border-radius: var(--radius-md); border: 1px solid var(--border-light);
  background: var(--bg-card); transition: var(--transition-base);
}
.step-item:hover { border-color: var(--border-color); }
.step-dot {
  width: 12px; height: 12px; border-radius: 50%; flex-shrink: 0;
}
.step-dot.done { background: var(--success); }
.step-dot.pending { background: var(--border-color); }
.step-dot.current { background: var(--primary); box-shadow: 0 0 0 4px rgba(37,99,235,0.2); }
.step-item .step-content { flex: 1; }
.step-item .step-label { font-weight: 600; font-size: 0.9rem; }
.step-item .step-desc { font-size: 0.78rem; color: var(--text-muted); }
.step-item .step-action a { font-size: 0.82rem; font-weight: 500; }

/* ═══════════════════════════════════════════
   列表组
   ═══════════════════════════════════════════ */
.list-group-item {
  border-radius: var(--radius-md) !important; margin-bottom: 8px;
  border: 1px solid var(--border-light) !important; padding: 14px 18px !important;
  background: var(--bg-card) !important; transition: var(--transition-fast);
}
.list-group-item:hover { border-color: var(--primary-light) !important; }

/* ═══════════════════════════════════════════
   导航栏下拉菜单
   ═══════════════════════════════════════════ */
.nav-dropdown { position: relative; display: inline-block; }
.nav-dropdown-toggle {
  padding: 6px 12px; border-radius: var(--radius-sm);
  color: var(--text-secondary); font-size: 0.875rem;
  font-weight: 500; background: transparent; border: none;
  cursor: pointer; display: inline-flex; align-items: center;
  white-space: nowrap; transition: var(--transition-fast);
  font-family: inherit; list-style: none;
}
.nav-dropdown-toggle::-webkit-details-marker { display: none; }
.nav-dropdown-toggle:hover { color: var(--primary); background: var(--primary-ghost); }
.nav-dropdown.active .nav-dropdown-toggle { color: var(--primary); background: var(--primary-light); }
.nav-dropdown-arrow { transition: transform 0.2s; }
.nav-dropdown[open] .nav-dropdown-arrow { transform: rotate(180deg); }
.nav-dropdown-menu {
  display: none;
  position: absolute; top: calc(100% + 4px); left: 0;
  min-width: 160px; background: var(--bg-card);
  border: 1px solid var(--border-light); border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg); padding: 6px; z-index: 1040;
}
.nav-dropdown[open] .nav-dropdown-menu { display: block; }
.nav-dropdown-menu a {
  display: block; padding: 8px 12px; border-radius: var(--radius-sm);
  color: var(--text-secondary); font-size: 0.875rem;
  font-weight: 500; text-decoration: none; white-space: nowrap;
  transition: var(--transition-fast);
}
.nav-dropdown-menu a:hover { color: var(--primary); background: var(--primary-ghost); }
.nav-dropdown-menu a.active { color: var(--primary); background: var(--primary-light); }
.nav-dropdown-menu a.nav-sub-item { padding-left: 30px; /* 对齐一级分组标题文字起点：12px padding + 12px 图标 + 6px 间距 */ }
.nav-item-icon {
  margin-right: 8px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  vertical-align: -0.15em;
  color: currentColor;
  opacity: 0.85;
}
.nav-item-icon svg { width: 14px; height: 14px; }
.nav-dropdown-group {
  padding: 8px 12px 4px;
  font-size: 0.72rem;
  color: var(--text-muted, #9ca3af);
  font-weight: 600;
  letter-spacing: 0.04em;
  cursor: default;
  user-select: none;
  display: flex;
  align-items: center;
}
.nav-dropdown-group .nav-item-icon { margin-right: 6px; opacity: 0.65; }
.nav-dropdown-group .nav-item-icon svg { width: 12px; height: 12px; }
.nav-dropdown-group:not(:first-child) { margin-top: 4px; border-top: 1px solid var(--border-light, #f1f5f9); }
/* 抽屉模式下拉菜单全宽展开（与导航抽屉断点一致：1100px 以下均为抽屉形态） */
@media (max-width: 1099.98px) {
  .nav-dropdown { width: 100%; }
  .nav-dropdown-toggle { width: 100%; justify-content: space-between; padding: 10px 12px; }
  .nav-dropdown-menu { position: static; width: 100%; box-shadow: none; border: none; padding: 4px 0 4px 16px; background: transparent; }
.nav-dropdown-group { padding-left: 12px; }
}

/* ═══════════════════════════════════════════
   动画
   ═══════════════════════════════════════════ */
@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }
@keyframes fadeInUp { from { opacity: 0; transform: translateY(24px); } to { opacity: 1; transform: translateY(0); } }
.animate-fade-in { animation: fadeIn 0.4s cubic-bezier(0.4,0,0.2,1) forwards; }
.animate-stagger > * { opacity: 0; animation: fadeIn 0.5s cubic-bezier(0.4,0,0.2,1) forwards; }
.animate-stagger > *:nth-child(1) { animation-delay: 0.05s; }
.animate-stagger > *:nth-child(2) { animation-delay: 0.1s; }
.animate-stagger > *:nth-child(3) { animation-delay: 0.15s; }
.animate-stagger > *:nth-child(4) { animation-delay: 0.2s; }
.animate-stagger > *:nth-child(5) { animation-delay: 0.25s; }
.animate-stagger > *:nth-child(6) { animation-delay: 0.3s; }

/* ═══════════════════════════════════════════
   学习页面专用
   ═══════════════════════════════════════════ */
body:has(.learning-page) .app-nav { position: relative; }

/* ═══════════════════════════════════════════
   工具类
   ═══════════════════════════════════════════ */
.text-primary-app { color: var(--primary) !important; }
.text-muted-app { color: var(--text-muted) !important; }
.text-sm { font-size: 0.85rem; }
.text-xs { font-size: 0.75rem; }
.bg-primary-app { background: var(--primary) !important; }
.rounded-app { border-radius: var(--radius-lg) !important; }
.cursor-pointer { cursor: pointer; }
.fw-700 { font-weight: 700; }
.fw-800 { font-weight: 800; }

/* ── Badge 文字颜色修复（Tabler CSS 默认灰色）── */
.badge { color: #fff !important; }

/* ═══════════════════════════════════════════
   导航栏通知红点
   ═══════════════════════════════════════════ */
.nav-notify-badge {
  position: absolute; top: -4px; right: -8px;
  min-width: 18px; height: 18px; border-radius: 9px;
  background: #ef4444; color: #fff; font-size: 0.7rem;
  font-weight: 700; display: flex; align-items: center; justify-content: center;
  padding: 0 5px; line-height: 1; z-index: 1050;
  animation: notifyPopIn 0.3s cubic-bezier(0.68,-0.55,0.27,1.55);
}
.nav-notify-dot {
  display: inline-block; width: 8px; height: 8px;
  border-radius: 50%; background: #ef4444; z-index: 1050;
  margin-left: 4px; vertical-align: middle;
  animation: notifyPopIn 0.3s cubic-bezier(0.68,-0.55,0.27,1.55);
}
@keyframes notifyPopIn {
  from { transform: scale(0); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}