    body {
      font-family: 'Segoe UI', sans-serif;
      transition: background-color 0.3s, color 0.3s;
    }
    .sidebar {
      background: linear-gradient(135deg, #007bff 0%, #0056b3 100%);
      color: white;
      min-height: 100vh;
      padding: 0;
      transition: background 0.3s;
    }
    [data-bs-theme="dark"] .sidebar {
      background: linear-gradient(135deg, #111827, #1e293b);
    }
    .sidebar .nav-link {
      color: white;
      padding: 2rem 1.5rem;
      border-left: 4px solid transparent;
    }
    .sidebar .nav-link:hover,
    .sidebar .nav-link.active {
      background: rgba(255, 255, 255, 0.15);
      border-left-color: white;
    }
    .stat-card {
      transition: transform .2s;
    }
    .stat-card:hover {
      background: green;
      transform: translateY(-3px);
    }
    .toggle-btn {
      position: fixed;
      width: 150px;
      bottom: 0;
      right: 0;
      transform: translateX(-50%);
      background: rgba(255, 255, 255, 0.1);
      border: none;
      color: black;
      border-radius: 20px;
      font-size: 0.9rem;
      cursor: pointer;
      transition: all 0.3s ease;
      z-index: 1000;
    }
    .toggle-btn:hover {
      background: rgba(255, 255, 255, 0.3);
    }
