/* ============================================
   个人题库管理系统 - 统一设计系统
   Design System v1.0
   ============================================ */

/* ---- 设计令牌 ---- */
:root {
  /* 主色调 */
  --primary: #2f80ed;
  --primary-hover: #1b5fbf;
  --primary-light: rgba(47,128,237,.12);
  --primary-subtle: #e8f0fe;

  /* 语义色 */
  --success: #1e874b;
  --success-light: rgba(30,135,75,.12);
  --warning: #b26a00;
  --warning-light: rgba(243,156,18,.16);
  --danger: #c0392b;
  --danger-light: rgba(231,76,60,.14);
  --info: #2f80ed;
  --info-light: rgba(47,128,237,.12);

  /* 中性色 */
  --text: #1f2d3d;
  --text-secondary: #6b7b8c;
  --text-muted: #9caab8;
  --border: #e9eef5;
  --border-light: #f0f3f8;
  --surface: #ffffff;
  --surface-alt: #f5f7fa;
  --surface-raised: #ffffff;

  /* 圆角 */
  --radius-sm: 8px;
  --radius: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-pill: 9999px;

  /* 阴影 */
  --shadow-sm: 0 2px 8px rgba(31,45,61,.04);
  --shadow: 0 10px 30px rgba(31,45,61,.06);
  --shadow-lg: 0 20px 50px rgba(31,45,61,.08);
  --shadow-glow: 0 0 0 1px rgba(47,128,237,.1), 0 8px 24px rgba(31,45,61,.08);

  /* 字体 */
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;

  /* 间距 */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;

  /* 导航栏 */
  --navbar-bg: #1a2634;
  --navbar-text: #c8d6e5;
  --navbar-active: #ffffff;
  --navbar-hover-bg: rgba(255,255,255,.06);
  --navbar-height: 52px;

  /* 背景 */
  --body-bg: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  --body-bg-attachment: fixed;

  /* 过渡 */
  --transition-fast: .15s ease;
  --transition: .2s ease;
  --transition-slow: .3s ease;
}

/* ---- 基础样式 ---- */
html { height: 100%; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background: var(--body-bg);
  background-repeat: no-repeat;
  background-size: cover;
  background-attachment: var(--body-bg-attachment);
  min-height: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ---- 滚动条美化 ---- */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: #c8d6e5;
  border-radius: var(--radius-pill);
}
::-webkit-scrollbar-thumb:hover { background: #a0b4c8; }

/* ---- 主容器 ---- */
.app-container {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  margin: 68px auto 30px;
  padding: 0;
  overflow: hidden;
  max-width: 1400px;
  width: calc(100% - 60px);
  transition: box-shadow var(--transition);
}

@media (max-width: 768px) {
  .app-container {
    margin: 60px 12px 20px;
    width: calc(100% - 24px);
    border-radius: var(--radius-sm);
  }
}

@media (min-width: 1600px) {
  .app-container { max-width: 1500px; }
}

/* ---- 页面内容区域 ---- */
.page-content {
  padding: 20px 24px 28px;
}

@media (max-width: 768px) {
  .page-content { padding: 14px 14px 20px; }
}

/* ---- 页面标题 ---- */
.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: 14px 18px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  margin-bottom: 14px;
}

.page-header h2 {
  margin: 0;
  color: var(--text);
  font-weight: 800;
  font-size: 18px;
  letter-spacing: -.01em;
}

.page-header h2 i {
  color: var(--primary);
  margin-right: 8px;
}

/* ---- 版块标题 ---- */
.section-title {
  margin: 16px 2px 10px;
  color: var(--text);
  font-weight: 800;
  font-size: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.section-title::before {
  content: "";
  width: 10px;
  height: 10px;
  border-radius: 3px;
  background: var(--primary-light);
  border: 1px solid rgba(47,128,237,.28);
}

/* ============================================
   导航栏组件
   ============================================ */
.navbar-custom {
  background: var(--navbar-bg) !important;
  box-shadow: 0 2px 12px rgba(0,0,0,.15);
  height: var(--navbar-height);
  padding: 0 16px;
}

.navbar-custom .navbar-brand,
.navbar-custom .navbar-brand:hover,
.navbar-custom .navbar-brand:focus {
  color: #fff !important;
}

.navbar-custom .navbar-nav .nav-link {
  color: var(--navbar-text);
  font-weight: 500;
  font-size: 14px;
  padding: 14px 12px;
  transition: all var(--transition-fast);
  border-radius: 6px;
  position: relative;
  white-space: nowrap;
}

.navbar-custom .navbar-nav .nav-link:hover,
.navbar-custom .navbar-nav .nav-link:focus {
  color: var(--navbar-active);
  background: var(--navbar-hover-bg);
}

.navbar-custom .navbar-nav .nav-link.active {
  color: var(--navbar-active);
}

.navbar-custom .navbar-nav .nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 3px;
  background: var(--primary);
  border-radius: 2px 2px 0 0;
}

.navbar-custom .navbar-nav .nav-link i {
  color: var(--primary);
  margin-right: 6px;
  font-size: 14px;
  width: 18px;
  text-align: center;
}

.navbar-custom .navbar-nav .nav-link:hover i {
  color: #5faaff;
}

/* 导航下拉菜单 */
.navbar-custom .dropdown-menu {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-lg);
  padding: 6px;
  margin-top: 6px;
  border: none;
  min-width: 200px;
}

.navbar-custom .dropdown-menu .dropdown-item {
  color: var(--text);
  font-size: 13px;
  padding: 8px 12px;
  border-radius: 6px;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 8px;
}

.navbar-custom .dropdown-menu .dropdown-item:hover {
  background: var(--primary-subtle);
  color: var(--primary);
}

.navbar-custom .dropdown-menu .dropdown-item i {
  color: var(--text-muted);
  width: 18px;
  text-align: center;
  font-size: 14px;
  transition: color var(--transition-fast);
}

.navbar-custom .dropdown-menu .dropdown-item:hover i {
  color: var(--primary);
}

.navbar-custom .dropdown-menu .dropdown-divider {
  margin: 4px 0;
  border-color: var(--border-light);
}

/* 用户头像占位 */
.navbar-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--primary-light);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  font-size: 14px;
  font-weight: 700;
}

/* 危险操作项 */
.dropdown-item.is-danger {
  color: var(--danger) !important;
}
.dropdown-item.is-danger:hover {
  background: var(--danger-light) !important;
  color: var(--danger) !important;
}

/* 导航栏切换按钮 */
.navbar-custom .navbar-toggler {
  border: none;
  padding: 6px 8px;
  color: var(--navbar-text);
}

.navbar-custom .navbar-toggler:focus {
  box-shadow: none;
}

@media (max-width: 991.98px) {
  .navbar-custom .navbar-collapse {
    background: var(--navbar-bg);
    border-radius: 0 0 var(--radius-sm) var(--radius-sm);
    padding: 8px 0;
    max-height: calc(100vh - var(--navbar-height));
    overflow-y: auto;
  }

  .navbar-custom .navbar-nav .nav-link {
    padding: 10px 16px;
    border-radius: 0;
  }

  .navbar-custom .navbar-nav .nav-link.active::after {
    display: none;
  }

  .navbar-custom .navbar-nav .nav-link.active {
    background: var(--navbar-hover-bg);
  }
}

/* ============================================
   卡片组件
   ============================================ */
.card-custom {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition);
}

.card-custom:hover {
  box-shadow: var(--shadow);
}

.card-custom .card-header-custom {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
  background: linear-gradient(180deg, #f7fbff 0%, #f3f8ff 100%);
}

.card-custom .card-body-custom {
  padding: 18px;
}

/* 统计卡片 */
.stat-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition);
}

.stat-card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

/* ============================================
   统计徽标
   ============================================ */
.stats-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 8px;
}

.stat-pill {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  font-size: 12px;
  font-weight: 800;
  border: 1px solid transparent;
}

.stat-pill.correct {
  color: var(--success);
  background: var(--success-light);
  border-color: rgba(30,135,75,.25);
}

.stat-pill.partial {
  color: var(--warning);
  background: var(--warning-light);
  border-color: rgba(243,156,18,.30);
}

.stat-pill.wrong {
  color: var(--danger);
  background: var(--danger-light);
  border-color: rgba(231,76,60,.28);
}

.stat-pill.total {
  color: var(--text-secondary);
  background: #f0f3f8;
  border-color: var(--border);
}

/* 状态徽章 */
.badge-status {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  border-radius: var(--radius-pill);
  font-weight: 700;
  font-size: 12px;
  border: 1px solid transparent;
}

.badge-status.correct {
  color: var(--success);
  background: var(--success-light);
  border-color: rgba(30,135,75,.25);
}

.badge-status.partial {
  color: var(--warning);
  background: var(--warning-light);
  border-color: rgba(243,156,18,.30);
}

.badge-status.wrong {
  color: var(--danger);
  background: var(--danger-light);
  border-color: rgba(231,76,60,.28);
}

/* ============================================
   表格组件
   ============================================ */
.table-custom {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  font-size: 13px;
}

.table-custom thead th {
  background: linear-gradient(180deg, #f7fbff 0%, #f3f8ff 100%);
  font-weight: 700;
  font-size: 12px;
  color: var(--text-secondary);
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  text-align: left;
  letter-spacing: .02em;
}

.table-custom tbody td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border-light);
  vertical-align: middle;
}

.table-custom tbody tr {
  transition: background var(--transition-fast);
}

.table-custom tbody tr:hover {
  background: #f8fbff;
}

.table-custom tbody tr:last-child td {
  border-bottom: none;
}

/* ============================================
   按钮变体
   ============================================ */
.btn-ghost {
  background: #fff;
  color: var(--text);
  border: 1px solid var(--border);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  text-decoration: none;
}

.btn-ghost:hover {
  border-color: #cfe0ff;
  color: var(--primary);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

/* 操作按钮（表格内） */
.action-btn {
  padding: 4px 8px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 11px;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  background: transparent;
  color: var(--text-secondary);
}

.action-btn:hover {
  transform: none;
  box-shadow: none;
}

.action-btn.edit:hover {
  background: #fff3cd;
  border-color: var(--warning);
  color: var(--warning);
}

.action-btn.delete:hover {
  background: var(--danger-light);
  border-color: var(--danger);
  color: var(--danger);
}

/* ============================================
   知识点标签
   ============================================ */
.knowledge-tag {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 11px;
  font-weight: 600;
  margin: 2px 3px;
  letter-spacing: .02em;
  transition: transform .15s ease, box-shadow .15s ease;
}

.knowledge-tag:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(0,0,0,.15);
}

.knowledge-tag-sm {
  font-size: 10px;
  padding: 2px 8px;
  margin: 1px 2px;
}

/* 知识点颜色变体（通过数据属性驱动） */
.knowledge-tag[data-color="0"] { background: #2f80ed; color: #fff; }
.knowledge-tag[data-color="0"]::before { background: rgba(255,255,255,.5); }
.knowledge-tag[data-color="1"] { background: #e74c3c; color: #fff; }
.knowledge-tag[data-color="1"]::before { background: rgba(255,255,255,.5); }
.knowledge-tag[data-color="2"] { background: #27ae60; color: #fff; }
.knowledge-tag[data-color="2"]::before { background: rgba(255,255,255,.5); }
.knowledge-tag[data-color="3"] { background: #8e44ad; color: #fff; }
.knowledge-tag[data-color="3"]::before { background: rgba(255,255,255,.5); }
.knowledge-tag[data-color="4"] { background: #f39c12; color: #fff; }
.knowledge-tag[data-color="4"]::before { background: rgba(255,255,255,.5); }
.knowledge-tag[data-color="5"] { background: #1abc9c; color: #fff; }
.knowledge-tag[data-color="5"]::before { background: rgba(255,255,255,.5); }
.knowledge-tag[data-color="6"] { background: #e67e22; color: #fff; }
.knowledge-tag[data-color="6"]::before { background: rgba(255,255,255,.5); }
.knowledge-tag[data-color="7"] { background: #3498db; color: #fff; }
.knowledge-tag[data-color="7"]::before { background: rgba(255,255,255,.5); }

/* ============================================
   头像组件
   ============================================ */
.avatar-group {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  overflow: hidden;
  flex-shrink: 0;
  background: var(--surface-alt);
}

.avatar-group .avatar {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* ============================================
   加载状态
   ============================================ */
.loading-spinner {
  text-align: center;
  font-size: 14px;
  padding: 40px 20px;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.loading-spinner::before {
  content: "";
  width: 20px;
  height: 20px;
  border: 2px solid var(--primary);
  border-top-color: transparent;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ============================================
   动画工具
   ============================================ */
.fade-in {
  animation: fadeIn .3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.slide-down {
  animation: slideDown .25s ease;
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ============================================
   表单美化
   ============================================ */
.form-control-custom {
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 12px;
  font-size: 14px;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-control-custom:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-light);
  outline: none;
}

/* ============================================
   模态框美化
   ============================================ */
.modal-custom .modal-content {
  border: none;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
}

.modal-custom .modal-header {
  border-bottom: 1px solid var(--border);
  padding: 16px 20px;
}

.modal-custom .modal-footer {
  border-top: 1px solid var(--border);
  padding: 12px 20px;
}

.modal-custom .modal-body {
  padding: 20px;
}

/* ============================================
   提示框美化
   ============================================ */
.toast-container-custom {
  position: fixed;
  top: 70px;
  right: 20px;
  z-index: 99999;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.toast-custom {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  animation: slideDown .3s ease;
  min-width: 280px;
}

.toast-custom.success { border-left: 3px solid var(--success); }
.toast-custom.error { border-left: 3px solid var(--danger); }
.toast-custom.warning { border-left: 3px solid var(--warning); }
.toast-custom.info { border-left: 3px solid var(--primary); }

/* ============================================
   空状态
   ============================================ */
.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-muted);
}

.empty-state i {
  font-size: 48px;
  margin-bottom: 16px;
  opacity: .5;
}

.empty-state h4 {
  font-size: 18px;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.empty-state p {
  font-size: 14px;
  margin: 0;
}

/* ============================================
   分页
   ============================================ */
.pagination-custom {
  display: flex;
  align-items: center;
  gap: 4px;
  flex-wrap: wrap;
}

.pagination-custom .btn-page {
  padding: 6px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text-secondary);
  font-size: 13px;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.pagination-custom .btn-page:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--primary-subtle);
}

.pagination-custom .btn-page.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.pagination-custom .btn-page:disabled {
  opacity: .5;
  cursor: not-allowed;
}