/* ============================================================
   用户中心模板：朝气蓬勃、炫亮风格
   主字体 12px，层次清晰
   布局：顶栏（user-topbar）+ 左侧菜单（user-sidebar）
         + 主区（user-main）+ 底栏（user-footer）
   ============================================================ */

:root {
  /* 主题色（炫亮渐变） */
  --c-primary: #3b82f6;
  --c-primary-dark: #2563eb;
  --c-primary-light: #60a5fa;
  --c-accent: #f97316;   /* 橙色点缀 */
  --c-accent2: #06b6d4;  /* 青色点缀 */
  --c-success: #16a34a;
  --c-warning: #f59e0b;
  --c-danger: #ef4444;

  /* 文字色 */
  --c-text: #1f2937;
  --c-text-sub: #4b5563;
  --c-text-mute: #6b7280;

  /* 背景色 */
  --c-bg: #f0f5ff;          /* 浅蓝主背景 */
  --c-bg-soft: #f8faff;     /* 更淡的蓝 */
  --c-bg-card: #ffffff;
  --c-bg-side: #ffffff;
  --c-bg-topbar: linear-gradient(90deg, #3b82f6 0%, #6366f1 50%, #06b6d4 100%);

  /* 边框/分隔 */
  --c-border: #e5e7eb;
  --c-border-soft: #eef2ff;
  --c-divider: #edf2ff;

  /* 阴影 */
  --shadow-card: 0 2px 6px rgba(59, 130, 246, 0.08), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-card-hover: 0 8px 24px rgba(59, 130, 246, 0.18), 0 2px 6px rgba(0, 0, 0, 0.04);
  --shadow-soft: 0 1px 2px rgba(0, 0, 0, 0.04);

  /* 尺寸 */
  --topbar-h: 60px;
  --sidebar-w: 210px;
  --footer-h: 56px;
  --radius: 10px;

  /* 字体（12px 为主） */
  --font-body: 12px;
  --font-sm: 11px;
  --font-md: 13px;
  --font-lg: 14px;
  --font-title: 18px;
  --font-h1: 22px;
}

/* ========== Reset ========== */
* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: var(--font-body);
  color: var(--c-text);
  line-height: 1.6;
  background: var(--c-bg);
  min-height: 100vh;
}
a { color: var(--c-primary); text-decoration: none; transition: color .15s; }
a:hover { color: var(--c-primary-dark); }
img { max-width: 100%; display: block; }
button { font-family: inherit; }

/* ========== 页面整体布局 ========== */
/* 顶部固定导航 */
#userTopBar {
  height: var(--topbar-h);
  background: var(--c-bg-topbar);
  color: #fff;
  display: flex;
  align-items: center;
  padding: 0 24px;
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.35);
}
#userTopBar .brand {
  font-size: var(--font-lg);
  font-weight: 700;
  letter-spacing: 2px;
  display: flex;
  align-items: center;
  gap: 8px;
  margin-right: 32px;
  flex: none;
}
#userTopBar .brand span {
  background: linear-gradient(90deg, #fde68a, #fff);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.15);
}
#userTopBar .nav {
  display: flex;
  align-items: center;
  gap: 4px;
  flex: 1;
  overflow-x: auto;
  scrollbar-width: none;
}
#userTopBar .nav::-webkit-scrollbar { display: none; }
#userTopBar .nav a {
  color: rgba(255, 255, 255, 0.92);
  padding: 8px 14px;
  border-radius: 8px;
  font-size: var(--font-md);
  white-space: nowrap;
  transition: background .2s, transform .2s;
  position: relative;
}
#userTopBar .nav a:hover {
  background: rgba(255, 255, 255, 0.18);
  transform: translateY(-1px);
  text-decoration: none;
}
#userTopBar .nav a.active {
  background: #fff;
  color: var(--c-primary-dark);
  font-weight: 600;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.12);
}
#userTopBar .nav-right { flex: none; display: flex; gap: 8px; align-items: center; }
#userTopBar .nav-right a {
  color: #fff;
  font-size: var(--font-md);
  padding: 6px 14px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.14);
  transition: background .2s, transform .2s;
}
#userTopBar .nav-right a:hover {
  background: rgba(255, 255, 255, 0.26);
  transform: translateY(-1px);
  text-decoration: none;
}

/* ========== 布局包裹 ========== */
.user-layout {
  display: flex;
  padding-top: var(--topbar-h);
  min-height: 100vh;
}

/* 左侧菜单 */
#userSidebar {
  width: var(--sidebar-w);
  background: var(--c-bg-side);
  position: fixed;
  top: var(--topbar-h);
  bottom: 0;
  left: 0;
  overflow-y: auto;
  padding: 16px 12px 20px;
  border-right: 1px solid var(--c-divider);
  box-shadow: 2px 0 10px rgba(59, 130, 246, 0.04);
}
#userSidebar .sb-group { margin-bottom: 16px; }
#userSidebar .sb-group.collapsed { margin-bottom: 8px; }
#userSidebar .sb-group-title {
  font-size: var(--font-sm);
  color: var(--c-text-mute);
  padding: 8px 12px 6px;
  letter-spacing: 1px;
  text-transform: uppercase;
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  user-select: none;
  border-radius: 6px;
  transition: background .15s;
}
#userSidebar .sb-group-title:hover { background: #f1f5f9; }
#userSidebar .sb-group-title .sb-toggle {
  font-size: 10px;
  color: var(--c-text-mute);
  transition: transform .25s;
}
#userSidebar .sb-group.collapsed .sb-group-title .sb-toggle {
  transform: rotate(-90deg);
}
#userSidebar .sb-group .sb-items {
  overflow: hidden;
  max-height: 500px;
  transition: max-height .3s ease, opacity .25s ease;
  opacity: 1;
}
#userSidebar .sb-group.collapsed .sb-items {
  max-height: 0;
  opacity: 0;
}
#userSidebar .sb-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border-radius: 8px;
  color: var(--c-text-sub);
  font-size: var(--font-md);
  margin-bottom: 2px;
  position: relative;
  transition: all .2s;
  cursor: pointer;
}
#userSidebar .sb-item .ic {
  width: 22px;
  height: 22px;
  border-radius: 6px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  background: linear-gradient(135deg, #dbeafe, #e0e7ff);
  color: var(--c-primary-dark);
  flex: none;
  transition: transform .3s;
}
#userSidebar .sb-item:hover {
  background: linear-gradient(90deg, #eef2ff, #ecfeff);
  color: var(--c-primary-dark);
  transform: translateX(2px);
}
#userSidebar .sb-item.active {
  background: linear-gradient(90deg, #3b82f6, #06b6d4);
  color: #fff;
  font-weight: 600;
  box-shadow: 0 6px 14px rgba(59, 130, 246, 0.35);
}
#userSidebar .sb-item.active .ic {
  background: rgba(255, 255, 255, 0.28);
  color: #fff;
}
#userSidebar .sb-item.active::before {
  content: "";
  position: absolute;
  left: -12px;
  top: 50%;
  transform: translateY(-50%);
  width: 4px;
  height: 18px;
  background: var(--c-accent);
  border-radius: 0 4px 4px 0;
}

/* 主区 */
#userMain {
  margin-left: var(--sidebar-w);
  flex: 1;
  padding: 24px 28px;
  min-width: 0;
  min-height: calc(100vh - var(--topbar-h) - var(--footer-h));
}

/* 底栏 */
#userFooter {
  margin-left: var(--sidebar-w);
  background: #fff;
  border-top: 1px solid var(--c-divider);
  padding: 16px 28px;
  text-align: center;
  color: var(--c-text-mute);
  font-size: var(--font-body);
}
#userFooter .footer-content { display: inline-flex; gap: 0; align-items: center; }
#userFooter a { color: var(--c-text-mute); transition: color .15s; }
#userFooter a:hover { color: var(--c-primary); }

/* ========== 页面头部 ========== */
.page-head {
  background: linear-gradient(135deg, #fff 0%, #eef2ff 60%, #ecfeff 100%);
  border: 1px solid var(--c-divider);
  border-radius: var(--radius);
  padding: 22px 26px;
  margin-bottom: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  box-shadow: var(--shadow-soft);
  position: relative;
  overflow: hidden;
}
.page-head::before {
  content: "";
  position: absolute;
  top: -40px;
  right: -40px;
  width: 180px;
  height: 180px;
  background: radial-gradient(circle, rgba(249, 115, 22, 0.25), transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}
.page-head h1 {
  font-size: var(--font-h1);
  color: var(--c-text);
  margin-bottom: 4px;
  font-weight: 700;
  letter-spacing: 1px;
}
.page-head h1::before {
  content: "";
  display: inline-block;
  width: 4px;
  height: 18px;
  background: linear-gradient(180deg, var(--c-primary), var(--c-accent2));
  margin-right: 10px;
  vertical-align: middle;
  border-radius: 2px;
}
.page-head p { color: var(--c-text-mute); font-size: var(--font-md); }
.page-head .head-stats {
  display: flex;
  gap: 18px;
  font-size: var(--font-md);
  color: var(--c-text-sub);
}
.page-head .head-stats strong {
  color: var(--c-primary-dark);
  font-size: var(--font-title);
  display: block;
  font-weight: 700;
}

/* ========== 卡片 ========== */
.card {
  background: var(--c-bg-card);
  border: 1px solid var(--c-border-soft);
  border-radius: var(--radius);
  padding: 22px 26px;
  box-shadow: var(--shadow-card);
  margin-bottom: 18px;
  transition: box-shadow .2s;
  position: relative;
  overflow: hidden;
}
.card:hover { box-shadow: var(--shadow-card-hover); }
.card::before {
  content: "";
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 3px;
  background: linear-gradient(180deg, var(--c-primary), var(--c-accent2));
  opacity: 0;
  transition: opacity .2s;
}
.card:hover::before { opacity: 1; }

.card h1 { font-size: var(--font-title); margin-bottom: 14px; color: var(--c-text); font-weight: 700; }
.card h2 { font-size: var(--font-lg); margin-bottom: 12px; color: var(--c-text); font-weight: 600; }

/* ========== 工具条 / 搜索 ========== */
.toolbar {
  display: flex;
  gap: 10px;
  align-items: center;
  margin-bottom: 18px;
  flex-wrap: wrap;
}
.toolbar input, .toolbar select {
  padding: 8px 12px;
  border: 1px solid var(--c-border);
  border-radius: 8px;
  font-size: var(--font-md);
  background: #fff;
  outline: none;
  transition: border-color .15s, box-shadow .15s;
  font-family: inherit;
}
.toolbar input:focus, .toolbar select:focus {
  border-color: var(--c-primary);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}
.toolbar input { min-width: 220px; flex: 1; }

/* ========== 按钮（炫亮特效） ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 8px 18px;
  min-height: 34px;
  background: linear-gradient(135deg, #3b82f6, #06b6d4);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: var(--font-md);
  cursor: pointer;
  font-weight: 500;
  letter-spacing: 1px;
  transition: all .2s;
  box-shadow: 0 3px 8px rgba(59, 130, 246, 0.3);
  text-decoration: none;
  line-height: 1;
  position: relative;
  overflow: hidden;
}
.btn::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.3);
  transform: translate(-50%, -50%);
  transition: width .4s, height .4s;
}
.btn:hover::after { width: 300px; height: 300px; }
.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(59, 130, 246, 0.45);
  color: #fff;
  text-decoration: none;
}
.btn:active { transform: translateY(0); box-shadow: 0 2px 6px rgba(59, 130, 246, 0.35); }

.btn.btn-ghost {
  background: #fff;
  color: var(--c-primary-dark);
  border: 1px solid var(--c-primary);
  box-shadow: 0 2px 6px rgba(59, 130, 246, 0.12);
}
.btn.btn-ghost:hover {
  background: linear-gradient(135deg, #eef2ff, #ecfeff);
  box-shadow: 0 6px 14px rgba(59, 130, 246, 0.22);
}
.btn.btn-ghost::after { background: rgba(59, 130, 246, 0.08); }

.btn.btn-orange { background: linear-gradient(135deg, #f97316, #ef4444); box-shadow: 0 3px 8px rgba(249, 115, 22, 0.35); }
.btn.btn-orange:hover { box-shadow: 0 6px 18px rgba(249, 115, 22, 0.5); }
.btn.btn-green  { background: linear-gradient(135deg, #10b981, #06b6d4); box-shadow: 0 3px 8px rgba(16, 185, 129, 0.3); }
.btn.btn-green:hover { box-shadow: 0 6px 18px rgba(16, 185, 129, 0.45); }
.btn.btn-danger { background: linear-gradient(135deg, #ef4444, #dc2626); box-shadow: 0 3px 8px rgba(239, 68, 68, 0.3); }
.btn.btn-danger:hover { box-shadow: 0 6px 18px rgba(239, 68, 68, 0.45); }

.btn[disabled] { opacity: 0.6; cursor: not-allowed; transform: none !important; }

/* ========== 表单 ========== */
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px 18px; }
.form-grid .full { grid-column: 1 / -1; }
.form-section-title {
  grid-column: 1 / -1;
  font-size: var(--font-md);
  font-weight: 600;
  color: var(--c-primary-dark);
  padding-bottom: 8px;
  margin-top: 6px;
  border-bottom: 2px solid var(--c-divider);
  position: relative;
}
.form-section-title::before {
  content: "";
  display: inline-block;
  width: 6px; height: 6px;
  background: var(--c-accent);
  border-radius: 50%;
  margin-right: 8px;
  vertical-align: middle;
}
.form-item label {
  display: block;
  font-size: var(--font-body);
  color: var(--c-text-sub);
  margin-bottom: 6px;
  font-weight: 500;
}
.form-item input, .form-item select, .form-item textarea {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid var(--c-border);
  border-radius: 8px;
  font-size: var(--font-md);
  background: #fff;
  outline: none;
  transition: border-color .15s, box-shadow .15s;
  box-sizing: border-box;
  font-family: inherit;
  color: var(--c-text);
}
.form-item textarea { resize: vertical; min-height: 80px; line-height: 1.7; }
.form-item input:focus, .form-item select:focus, .form-item textarea:focus {
  border-color: var(--c-primary);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.upload-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 6px; }
.upload-box {
  background: linear-gradient(135deg, #f8faff, #ecfeff);
  border: 1px dashed var(--c-border);
  border-radius: var(--radius);
  padding: 14px;
  transition: border-color .2s, background .2s;
}
.upload-box:hover { border-color: var(--c-primary); background: #eef2ff; }
.upload-box label {
  display: block;
  font-size: var(--font-body);
  color: var(--c-text-sub);
  margin-bottom: 10px;
  font-weight: 500;
}
.upload-area { display: flex; flex-direction: column; gap: 8px; align-items: flex-start; }
.upload-area img {
  max-width: 100%;
  max-height: 180px;
  border: 1px solid var(--c-divider);
  border-radius: 8px;
  background: #fff;
}
.upload-area .upload-empty {
  width: 100%;
  padding: 20px;
  border: 2px dashed var(--c-divider);
  border-radius: 8px;
  text-align: center;
  color: var(--c-text-mute);
  font-size: var(--font-sm);
}

/* ========== 信息行 ========== */
.info-row {
  display: flex;
  padding: 10px 4px;
  border-bottom: 1px dashed var(--c-divider);
  font-size: var(--font-md);
}
.info-row:last-child { border-bottom: none; }
.info-row .k { width: 130px; color: var(--c-text-mute); flex: none; }
.info-row .v { flex: 1; color: var(--c-text); }

/* ========== 徽章 / 状态 ========== */
.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: var(--font-sm);
  font-weight: 500;
  background: linear-gradient(135deg, #eef2ff, #ecfeff);
  color: var(--c-primary-dark);
  border: 1px solid #dbeafe;
}
.badge.green { background: linear-gradient(135deg, #d1fae5, #a7f3d0); color: #065f46; border-color: #a7f3d0; }
.badge.orange { background: linear-gradient(135deg, #ffedd5, #fed7aa); color: #9a3412; border-color: #fed7aa; }
.badge.red { background: linear-gradient(135deg, #fee2e2, #fecaca); color: #991b1b; border-color: #fecaca; }
.badge.cyan { background: linear-gradient(135deg, #ecfeff, #a5f3fc); color: #155e75; border-color: #a5f3fc; }

/* ========== Toast ========== */
.toast {
  position: fixed;
  top: 80px; right: 24px;
  background: linear-gradient(135deg, #111827, #374151);
  color: #fff;
  padding: 12px 20px;
  border-radius: 10px;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.18);
  z-index: 999;
  opacity: 0;
  transform: translateY(-8px);
  transition: opacity .25s, transform .25s;
  pointer-events: none;
  max-width: 340px;
  font-size: var(--font-md);
}
.toast.show { opacity: 1; transform: translateY(0); }
.toast.success { background: linear-gradient(135deg, #10b981, #06b6d4); }
.toast.error { background: linear-gradient(135deg, #ef4444, #f97316); }

/* ========== 加载中 ========== */
.loading {
  display: inline-block;
  width: 16px; height: 16px;
  border: 2px solid rgba(255,255,255,0.5);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ========== 课程卡片 ========== */
.course-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 18px; }
.course-card {
  background: #fff;
  border: 1px solid var(--c-divider);
  border-radius: 12px;
  overflow: hidden;
  transition: all .25s;
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
}
.course-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-card-hover); }
.course-card .cover {
  height: 130px;
  background: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 60%, #06b6d4 100%);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 36px;
  position: relative;
  overflow: hidden;
}
.course-card .cover::after {
  content: "";
  position: absolute;
  right: -30px; bottom: -30px;
  width: 120px; height: 120px;
  background: radial-gradient(circle, rgba(255,255,255,0.2), transparent 70%);
  border-radius: 50%;
}
.course-card .cover img { width: 100%; height: 100%; object-fit: cover; }
.course-card .body { padding: 14px 16px 16px; flex: 1; display: flex; flex-direction: column; }
.course-card .body h3 {
  font-size: var(--font-lg);
  color: var(--c-text);
  margin-bottom: 6px;
  font-weight: 600;
  line-height: 1.4;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
  min-height: 40px;
}
.course-card .body .desc {
  font-size: var(--font-body);
  color: var(--c-text-mute);
  margin-bottom: 10px;
  min-height: 38px;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}
.course-card .meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
  font-size: var(--font-body);
  color: var(--c-text-mute);
  margin-bottom: 10px;
}
.course-card .meta span { display: inline-flex; align-items: center; gap: 3px; }
.course-card .price { color: var(--c-danger); font-weight: 700; font-size: var(--font-md); }
.course-card .free { color: var(--c-success); font-weight: 700; }
.course-card .actions { margin-top: auto; display: flex; gap: 8px; }
.course-card .actions .btn { flex: 1; padding: 7px 0; min-height: 32px; font-size: var(--font-body); }

/* ========== 学习进度 / 列表（我的课程） ========== */
.learning-row {
  background: #fff;
  border: 1px solid var(--c-divider);
  border-radius: var(--radius);
  padding: 14px 18px;
  margin-bottom: 10px;
  display: flex;
  gap: 16px;
  align-items: center;
  box-shadow: var(--shadow-card);
  transition: all .2s;
}
.learning-row:hover { transform: translateY(-1px); box-shadow: var(--shadow-card-hover); }
.learning-row .thumb {
  width: 96px; height: 64px;
  border-radius: 8px;
  background: linear-gradient(135deg, #3b82f6, #06b6d4);
  color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 28px; flex: none;
  overflow: hidden;
}
.learning-row .thumb img { width: 100%; height: 100%; object-fit: cover; }
.learning-row .info { flex: 1; min-width: 0; }
.learning-row .info h3 { font-size: var(--font-lg); margin-bottom: 6px; font-weight: 600; }
.learning-row .info .desc { font-size: var(--font-body); color: var(--c-text-mute); margin-bottom: 8px; }
.learning-row .progress-wrap {
  display: flex; align-items: center; gap: 10px;
  font-size: var(--font-body);
  color: var(--c-text-mute);
}
.progress-bar {
  flex: 1;
  height: 8px;
  background: #eef2ff;
  border-radius: 999px;
  overflow: hidden;
  position: relative;
}
.progress-bar span {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, #3b82f6, #06b6d4);
  border-radius: 999px;
  transition: width .4s;
  position: relative;
}
.progress-bar span::after {
  content: "";
  position: absolute;
  top: 0; right: 0; bottom: 0;
  width: 30px;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.6));
  animation: shine 1.6s infinite;
}
@keyframes shine {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

/* ========== 题库 / 考试 / 证书通用列表 ========== */
.list-item {
  background: #fff;
  border: 1px solid var(--c-divider);
  border-radius: var(--radius);
  padding: 14px 18px;
  margin-bottom: 10px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: center;
  box-shadow: var(--shadow-card);
  transition: all .2s;
}
.list-item:hover { transform: translateX(2px); box-shadow: var(--shadow-card-hover); border-color: #c7d2fe; }
.list-item .main { flex: 1; min-width: 0; }
.list-item h3 { font-size: var(--font-lg); margin-bottom: 4px; font-weight: 600; }
.list-item p { font-size: var(--font-body); color: var(--c-text-mute); }
.list-item .meta { margin-top: 6px; display: flex; gap: 12px; color: var(--c-text-mute); font-size: var(--font-body); flex-wrap: wrap; }

/* ========== 空状态 ========== */
.empty-state {
  padding: 50px 20px;
  text-align: center;
  color: var(--c-text-mute);
  font-size: var(--font-md);
}
.empty-state::before {
  content: "📭";
  display: block;
  font-size: 44px;
  margin-bottom: 12px;
  opacity: 0.7;
}

/* ========== 课时学习页 ========== */
.lesson-card {
  background: #fff;
  border: 1px solid var(--c-divider);
  border-radius: var(--radius);
  padding: 16px 20px;
  margin-bottom: 12px;
  box-shadow: var(--shadow-card);
  transition: all .2s;
}
.lesson-card:hover { box-shadow: var(--shadow-card-hover); transform: translateY(-1px); }
.lesson-card h3 { font-size: var(--font-lg); margin-bottom: 6px; color: var(--c-text); font-weight: 600; }
.lesson-card h3::before {
  content: "🎬";
  margin-right: 8px;
}
.lesson-card p { font-size: var(--font-body); color: var(--c-text-mute); margin-bottom: 8px; }
.lesson-card .lesson-meta {
  display: flex;
  gap: 14px;
  font-size: var(--font-body);
  color: var(--c-text-mute);
  flex-wrap: wrap;
}

/* ========== 题库 / 答题卡片 ========== */
.quiz-box {
  background: linear-gradient(135deg, #fff 0%, #eef2ff 100%);
  border: 1px solid var(--c-divider);
  border-radius: var(--radius);
  padding: 22px 26px;
  box-shadow: var(--shadow-card);
}
.quiz-box .tag {
  display: inline-block;
  font-size: var(--font-body);
  color: var(--c-primary-dark);
  margin-bottom: 10px;
  padding: 2px 10px;
  background: #eef2ff;
  border-radius: 999px;
}
.quiz-box h3 { font-size: var(--font-lg); color: var(--c-text); margin-bottom: 16px; font-weight: 600; }
.quiz-box label.opt {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  background: #fff;
  border: 1px solid var(--c-divider);
  border-radius: 8px;
  margin-bottom: 8px;
  cursor: pointer;
  font-size: var(--font-md);
  transition: all .15s;
}
.quiz-box label.opt:hover { border-color: var(--c-primary); background: #eef2ff; transform: translateX(3px); }
.quiz-box label.opt input { margin: 0; }

/* ========== 证书卡 ========== */
.cert-card {
  background: linear-gradient(135deg, #fffbeb 0%, #ecfeff 50%, #eef2ff 100%);
  border: 2px solid transparent;
  border-radius: var(--radius);
  padding: 22px;
  margin-bottom: 14px;
  box-shadow: var(--shadow-card);
  position: relative;
  background-clip: padding-box;
}
.cert-card::before {
  content: "";
  position: absolute;
  inset: -2px;
  border-radius: var(--radius);
  padding: 2px;
  background: linear-gradient(135deg, #f97316, #06b6d4, #3b82f6);
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
          mask-composite: exclude;
  pointer-events: none;
}
.cert-card h3 {
  font-size: var(--font-title);
  color: #b45309;
  margin-bottom: 8px;
  font-weight: 700;
}
.cert-card .cert-meta {
  display: flex;
  gap: 18px;
  font-size: var(--font-body);
  color: var(--c-text-sub);
  flex-wrap: wrap;
  margin-top: 8px;
}
.cert-card .cert-meta span {
  background: rgba(255,255,255,0.7);
  padding: 3px 10px;
  border-radius: 999px;
  border: 1px solid var(--c-divider);
}

/* ========== 公告 ========== */
.ann {
  background: #fff;
  border: 1px solid var(--c-divider);
  border-radius: var(--radius);
  padding: 14px 18px;
  margin-bottom: 10px;
  box-shadow: var(--shadow-card);
  position: relative;
  transition: all .2s;
}
.ann:hover { transform: translateY(-1px); box-shadow: var(--shadow-card-hover); }
.ann h3 { font-size: var(--font-lg); color: var(--c-text); margin-bottom: 6px; font-weight: 600; }
.ann .time { font-size: var(--font-sm); color: var(--c-text-mute); margin-bottom: 6px; }
.ann p { color: var(--c-text-sub); font-size: var(--font-body); }

/* ========== 统计小卡（首页概览） ========== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 14px;
  margin-bottom: 20px;
}
.stat-card {
  background: #fff;
  border: 1px solid var(--c-divider);
  border-radius: var(--radius);
  padding: 18px 18px;
  box-shadow: var(--shadow-card);
  position: relative;
  overflow: hidden;
  transition: all .25s;
}
.stat-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-card-hover); }
.stat-card .stat-icon {
  position: absolute;
  right: 12px; top: 12px;
  width: 36px; height: 36px;
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px;
  color: #fff;
}
.stat-card.blue   .stat-icon { background: linear-gradient(135deg, #3b82f6, #6366f1); }
.stat-card.orange .stat-icon { background: linear-gradient(135deg, #f97316, #ef4444); }
.stat-card.green  .stat-icon { background: linear-gradient(135deg, #10b981, #06b6d4); }
.stat-card.cyan   .stat-icon { background: linear-gradient(135deg, #06b6d4, #3b82f6); }
.stat-card .num {
  font-size: 26px;
  font-weight: 700;
  color: var(--c-text);
  line-height: 1;
  margin-bottom: 6px;
  background: linear-gradient(135deg, #1f2937, #3b82f6);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.stat-card .label { color: var(--c-text-mute); font-size: var(--font-body); }

/* ========== 响应式 ========== */
@media (max-width: 900px) {
  :root { --sidebar-w: 170px; --topbar-h: 56px; }
  .page-head { flex-direction: column; align-items: flex-start; }
  #userTopBar .nav-right a { padding: 6px 10px; }
  #userTopBar .brand { margin-right: 16px; font-size: var(--font-md); }
}
@media (max-width: 720px) {
  .form-grid { grid-template-columns: 1fr; }
  .upload-grid { grid-template-columns: 1fr; }
  .user-layout { display: block; }
  #userSidebar { position: static; width: 100%; padding: 12px; border-right: none; border-bottom: 1px solid var(--c-divider); }
  #userSidebar .sb-group { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 8px; }
  #userSidebar .sb-group-title { width: 100%; padding: 6px 0; }
  #userSidebar .sb-item { padding: 6px 10px; font-size: var(--font-body); margin-bottom: 0; }
  #userSidebar .sb-item.active::before { display: none; }
  #userMain { margin-left: 0; padding: 16px; }
  #userFooter { margin-left: 0; }
}

/* ========== 兼容旧选择器（保留） ========== */
.footer { text-align: center; padding: 16px 20px; color: var(--c-text-mute); font-size: var(--font-body); }
.hint { font-size: var(--font-body); color: var(--c-text-mute); margin-top: 6px; }
.section-title { margin: 18px 0 12px; font-size: var(--font-lg); font-weight: 600; color: var(--c-text); }

/* ========== 登录 / 注册页面（auth-page） ========== */
.auth-page {
  min-height: 100vh;
  background:
    radial-gradient(circle at 15% 20%, rgba(249, 115, 22, 0.18) 0%, transparent 45%),
    radial-gradient(circle at 85% 80%, rgba(6, 182, 212, 0.22) 0%, transparent 50%),
    linear-gradient(135deg, #eff6ff 0%, #e0e7ff 50%, #ecfeff 100%);
  display: flex;
  flex-direction: column;
  padding: 0;
}
.auth-page .auth-top {
  padding: 18px 28px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: rgba(255,255,255,0.7);
  border-bottom: 1px solid rgba(59, 130, 246, 0.15);
  backdrop-filter: blur(8px);
}
.auth-page .auth-top .brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 15px;
  font-weight: 700;
  color: var(--c-text);
}
.auth-page .auth-top .brand img {
  max-height: 32px;
}
.auth-page .auth-top .nav-links a {
  font-size: var(--font-md);
  color: var(--c-text-sub);
  margin-left: 20px;
  transition: color .15s;
  text-decoration: none;
}
.auth-page .auth-top .nav-links a:hover { color: var(--c-primary); }

.auth-page .auth-main {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px 20px;
}
.auth-page .auth-wrap {
  width: 100%;
  max-width: 960px;
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 0;
  background: #fff;
  border-radius: 20px;
  overflow: hidden;
  box-shadow:
    0 20px 60px rgba(59, 130, 246, 0.18),
    0 8px 20px rgba(0, 0, 0, 0.06);
  border: 1px solid rgba(59, 130, 246, 0.08);
}
.auth-page .auth-hero {
  padding: 50px 40px;
  background: linear-gradient(135deg, #3b82f6 0%, #6366f1 50%, #06b6d4 100%);
  color: #fff;
  position: relative;
  overflow: hidden;
}
.auth-page .auth-hero::before,
.auth-page .auth-hero::after {
  content: "";
  position: absolute;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.15);
}
.auth-page .auth-hero::before { width: 260px; height: 260px; top: -80px; right: -80px; }
.auth-page .auth-hero::after  { width: 180px; height: 180px; bottom: -60px; left: -40px; background: rgba(249, 115, 22, 0.25); }
.auth-page .auth-hero-inner { position: relative; z-index: 1; }
.auth-page .auth-hero h2 {
  font-size: 28px;
  font-weight: 800;
  margin-bottom: 18px;
  line-height: 1.35;
}
.auth-page .auth-hero p {
  color: rgba(255, 255, 255, 0.9);
  font-size: 13px;
  line-height: 1.7;
  margin-bottom: 24px;
}
.auth-page .auth-hero .feature-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.auth-page .auth-hero .feature-list li {
  padding: 10px 0;
  font-size: 13px;
  display: flex;
  align-items: center;
  gap: 10px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.15);
}
.auth-page .auth-hero .feature-list li:last-child { border-bottom: none; }
.auth-page .auth-hero .feature-list li span.ico {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  color: #fff;
}
.auth-page .auth-hero .brand-lg {
  font-size: 56px;
  font-weight: 900;
  letter-spacing: 4px;
  margin-bottom: 8px;
  background: linear-gradient(135deg, #fff 0%, #fde68a 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  line-height: 1;
}
.auth-page .auth-hero .brand-sub {
  font-size: 14px;
  letter-spacing: 6px;
  opacity: 0.9;
  margin-bottom: 28px;
}
.auth-page .auth-hero .brand-badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.18);
  font-size: var(--font-md);
  margin-bottom: 14px;
  letter-spacing: 2px;
}

.auth-page .auth-form {
  padding: 40px 44px;
}
.auth-page .auth-form .form-title {
  font-size: 22px;
  font-weight: 800;
  color: var(--c-text);
  margin-bottom: 8px;
}
.auth-page .auth-form .form-subtitle {
  color: var(--c-text-mute);
  font-size: 13px;
  margin-bottom: 26px;
}
.auth-page .auth-form .field {
  margin-bottom: 18px;
}
.auth-page .auth-form label {
  display: block;
  margin-bottom: 8px;
  color: var(--c-text-sub);
  font-size: var(--font-md);
  font-weight: 500;
}
.auth-page .auth-form .input-wrap {
  position: relative;
  display: flex;
  align-items: center;
}
.auth-page .auth-form .input-wrap .ico {
  position: absolute;
  left: 14px;
  font-size: 15px;
  color: var(--c-text-mute);
  pointer-events: none;
}
.auth-page .auth-form .input-wrap input {
  width: 100%;
  padding: 12px 14px 12px 42px;
  font-size: 14px;
  border: 1px solid #dbeafe;
  border-radius: 10px;
  background: #f8fafc;
  color: var(--c-text);
  outline: none;
  transition: all .18s;
  font-family: inherit;
}
.auth-page .auth-form .input-wrap input:focus {
  background: #fff;
  border-color: var(--c-primary);
  box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.15);
}
.auth-page .auth-form .form-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 14px 0 22px;
  font-size: 12px;
  color: var(--c-text-mute);
}
.auth-page .auth-form .submit-btn {
  width: 100%;
  padding: 12px 20px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 2px;
  background: linear-gradient(135deg, #3b82f6, #06b6d4);
  color: #fff;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  box-shadow: 0 6px 20px rgba(59, 130, 246, 0.35);
  transition: transform .15s, box-shadow .15s;
}
.auth-page .auth-form .submit-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 28px rgba(59, 130, 246, 0.45);
}
.auth-page .auth-form .alt-links {
  margin-top: 20px;
  text-align: center;
  font-size: 13px;
  color: var(--c-text-mute);
}
.auth-page .auth-form .alt-links a {
  color: var(--c-primary);
  text-decoration: none;
  margin: 0 4px;
}
.auth-page .auth-form .alt-links a:hover { text-decoration: underline; }

.auth-page .auth-footer {
  text-align: center;
  padding: 14px 28px 22px;
  font-size: 12px;
  color: var(--c-text-mute);
}

@media (max-width: 780px) {
  .auth-page .auth-wrap {
    grid-template-columns: 1fr;
    max-width: 420px;
  }
  .auth-page .auth-hero { display: none; }
  .auth-page .auth-form { padding: 32px 28px; }
}

/* ========== 用户头像小图标 ========== */
.avatar-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px 4px 4px;
  border-radius: 999px;
  background: rgba(255,255,255,0.18);
  font-size: var(--font-md);
  color: #fff;
}
.points-chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(250, 204, 21, 0.2);
  font-size: 13px;
  font-weight: 500;
  color: #fef3c7;
  margin-right: 8px;
}
.points-chip:hover { background: rgba(250, 204, 21, 0.3); }
.avatar-chip .dot {
  width: 26px; height: 26px;
  background: linear-gradient(135deg, #f97316, #fde68a);
  border-radius: 50%;
  display: inline-flex;
  align-items: center; justify-content: center;
  color: #7c2d12;
  font-weight: 700;
  font-size: var(--font-body);
}