/* Custom filter button base */
  .filter-btn {
    display: inline-flex;
    align-items: center;
    padding: 0.375rem 0.75rem;
    font-size: 0.95rem;
    font-weight: 500;
    line-height: 1.5;
    border-radius: 0.375rem;
    border: 1px solid transparent;
    background-color: #f8f9fa;
    color: #495057;
    cursor: pointer;
    transition: none; /* ← disables all transitions */
    text-decoration: none;
    user-select: none;
  }

  /* Prevent Bootstrap focus ring */
  .filter-btn:focus {
    outline: none !important;
    box-shadow: none !important;
  }

  /* Subject: soft blue */
  .filter-btn-subject {
    border-color: #cfe2ff;
    background-color: #e7f1ff;
    color: #0d6efd;
  }

  /* Level: soft green */
  .filter-btn-level {
    border-color: #d1e7dd;
    background-color: #e8f5e9;
    color: #198754;
  }

  /* Hover: keep it subtle — just darken background slightly */
  .filter-btn-subject:hover {
    background-color: #daeaff;
  }
  .filter-btn-level:hover {
    background-color: #d9f0db;
  }

  /* Active / Open Dropdown */
  .dropdown.show .filter-btn-subject {
    background-color: #cfe2ff;
    color: #0a58ca;
  }
  .dropdown.show .filter-btn-level {
    background-color: #d1e7dd;
    color: #146b3a;
  }