.main-content {
      padding: 2rem;
      background-color: #f8f9fa;
      min-height: calc(100vh - 60px);
      margin-top: 60px;
      margin-left: 200px;
      font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
    }
    .page-header {
      margin-bottom: 2rem;
      border-bottom: 1px solid #dee2e6;
      padding-bottom: 1rem;
    }
    .page-title {
      font-size: 1.75rem;
      font-weight: 600;
      color: #2c3e50;
      margin: 0;
      letter-spacing: 0.5px;
    }
    .card {
      border: none;
      box-shadow: 0 0 20px rgba(0, 0, 0, 0.05);
      border-radius: 10px;
    }
    .form-label {
      font-weight: 600;
      color: #2c3e50;
      font-size: 1rem;
      margin-bottom: 0.5rem;
    }
    .form-label span {
      font-weight: normal;
      color: #adb5bd;
      font-size: 0.75rem;
      margin-left: 0.5rem;
      display: block;
      margin-top: 0.25rem;
    }
    .sort-label span {
      display: inline !important;
      margin-top: 0 !important;
      font-size: 0.65rem !important;
    }
    .form-control {
      font-size: 0.95rem;
      padding: 0.75rem 1rem;
      border-radius: 8px;
      border: 1px solid #ced4da;
      transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
    }
    .form-control:focus {
      border-color: #80bdff;
      box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
    }
    .form-text {
      color: #6c757d;
      font-size: 0.875rem;
      margin-top: 0.25rem;
    }
    .btn-primary {
      background-color: #007bff;
      border-color: #007bff;
      padding: 0.5rem 1.5rem;
      font-weight: 500;
      letter-spacing: 0.5px;
    }
    .btn-secondary {
      background-color: #6c757d;
      border-color: #6c757d;
      padding: 0.5rem 1.5rem;
      font-weight: 500;
      letter-spacing: 0.5px;
    }
    .alert {
      font-size: 0.95rem;
      border-radius: 8px;
    }
    .invalid-feedback {
      font-size: 0.875rem;
      margin-top: 0.25rem;
    }