/* =============================================
 * 响应式适配
 * 断点：768px 平板 / 480px 手机
 * ============================================= */

/* 中等屏幕 - 平板竖屏 / 小窗口 */
@media (max-width: 1024px) {
  .sidebar {
    width: 200px;
  }
  .main-content {
    margin-left: 200px;
  }
}

/* 平板 & 小屏 */
@media (max-width: 768px) {
  .sidebar {
    width: 60px;
    overflow: hidden;
  }
  .sidebar .nav-text,
  .sidebar .group-list {
    display: none;
  }
  .main-content {
    margin-left: 60px;
    padding: 12px;
  }
  .stats-cards {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }
  .modal-content {
    width: 95vw;
    max-height: 90vh;
    margin: 5vh auto;
    border-radius: var(--radius-md);
  }
  .table-wrapper {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
  table {
    min-width: 600px;
  }
  .group-card {
    width: calc(50% - 8px);
  }
  h1 { font-size: 1.6rem; }
  h2 { font-size: 1.3rem; }
  h3 { font-size: 1.1rem; }
}

/* 手机 */
@media (max-width: 480px) {
  .sidebar {
    width: 100%;
    height: 56px;
    position: fixed;
    bottom: 0;
    left: 0;
    flex-direction: row;
    overflow-x: auto;
    z-index: 100;
  }
  .sidebar .nav-item {
    flex-shrink: 0;
    padding: 4px 10px;
  }
  .main-content {
    margin-left: 0;
    margin-bottom: 56px;
    padding: 8px;
  }
  .stats-cards {
    grid-template-columns: 1fr 1fr;
    gap: 6px;
  }
  .stat-card {
    padding: 10px;
  }
  .stat-card .value {
    font-size: 1.2rem;
  }
  .action-bar {
    flex-wrap: wrap;
    gap: 5px;
  }
  .action-bar .btn {
    font-size: 0.85rem;
    padding: 6px 10px;
  }
  .modal-content {
    width: 100vw;
    max-height: 100vh;
    margin: 0;
    border-radius: 0;
  }
  .group-card {
    width: 100%;
  }
  .student-avatar {
    width: 32px;
    height: 32px;
    font-size: 0.75rem;
  }
  h1 { font-size: 1.4rem; }
  h2 { font-size: 1.15rem; }
  h3 { font-size: 1rem; }
  .tooltip {
    display: none !important;
  }
  .btn-group {
    flex-wrap: wrap;
  }
  .theme-toggle {
    top: 8px;
    right: 8px;
    width: 32px;
    height: 32px;
    font-size: 14px;
  }
}

/* 大屏优化 */
@media (min-width: 1600px) {
  .stats-cards {
    grid-template-columns: repeat(4, 1fr);
  }
}