/* Sidebar */
      #sidebar {
        background: linear-gradient(180deg, #6d28d9, #9333ea);
        min-height: 100vh;
        transition: transform 0.3s ease-in-out;
        color: #fff;
        z-index: 1050;
        width: 220px;
      }
      #sidebar a {
        color: #f3f4f6;
        font-weight: 500;
        border-radius: 0.5rem;
        padding: 0.6rem 1rem;
        display: flex;
        align-items: center;
        gap: 10px;
        transition: background 0.2s;
      }
      #sidebar a:hover {
        background: rgba(255, 255, 255, 0.2);
      }

      /* Mobile sidebar hidden by default */
      @media (max-width: 768px) {
        #sidebar {
          transform: translateX(-100%);
          position: fixed;
          top: 0;
          left: 0;
        }
        #sidebar.active {
          transform: translateX(0);
        }
        #overlay {
          display: none;
        }
        #overlay.show {
          display: block;
          position: fixed;
          top: 0;
          left: 0;
          width: 100%;
          height: 100%;
          background: rgba(0, 0, 0, 0.5);
          z-index: 1040;
        }
        #main-content {
          margin-left: 0 !important; /* mobile pe full width */
        }
      }

      /* Desktop fix */
      @media (min-width: 769px) {
        #sidebar {
          position: fixed;
          top: 0;
          left: 0;
        }
        #main-content {
          margin-left: 220px; /* sidebar ke width ke equal */
        }
      }

      /* Cards */
      .card-custom {
        border-radius: 1rem;
        background: #fff;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
        transition: transform 0.2s;
      }
      .card-custom:hover {
        transform: translateY(-3px);
      }

      /* Topbar */
      .topbar {
        background: #fff;
        padding: 0.8rem 1rem;
        border-radius: 0.75rem;
        box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
      }
      chevron {
        transition: transform 0.3s ease;
      }
      .rotate {
        transform: rotate(180deg);
      }

      /* Slide + Fade animation */
      .submenu {
        max-height: 0;
        overflow: hidden;
        opacity: 0;
        transform: translateY(-5px);
        transition: max-height 0.4s ease, opacity 0.4s ease, transform 0.3s ease;
      }
      .submenu.show {
        max-height: 500px; /* बड़ा value ताकि submenu पूरा खुल सके */
        opacity: 1;
        transform: translateY(0);
      }
      /* student Form  */
       .form-card {
      background: #fff;
      border-radius: 1rem;
      padding: 2rem;
      box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    }
    label {
      font-weight: 600;
      margin-bottom: 0.3rem;
      color: #374151;
    }
    .form-control, .form-select {
      border-radius: 0.6rem;
      padding: 0.6rem 0.75rem;
      border: 1px solid #d1d5db;
    }
    .form-control:focus, .form-select:focus {
      border-color: #6d28d9;
      box-shadow: 0 0 0 0.2rem rgba(109,40,217,0.25);
    }
    .btn-submit {
      background: linear-gradient(90deg, #6d28d9, #9333ea);
      color: #fff;
      font-weight: 600;
      border-radius: 0.75rem;
      padding: 0.75rem;
      transition: background 0.3s ease;
    }
    .btn-submit:hover {
      background: linear-gradient(90deg, #5b21b6, #7e22ce);
    }
      /* student form close */