.collapsible {
          background-color: #777;
          color: white;
          cursor: pointer;
          padding: 18px;
          width: 100%;
          border: none;
          text-align: left;
          outline: none;
          font-size: 15px;
        }
        
        .active, .collapsible:hover {
          background-color: #555;
        }
        
        .collapsible:after {
          content: '\002B';
          color: white;
          font-weight: bold;
          float: right;
          margin-left: 5px;
        }
        
        .active:after {
          content: "\2212";
        }
        
        .collapsibleContent {
          padding: 0 18px;
          max-height: 0;
          overflow: hidden;
          transition: max-height 0.2s ease-out;
          background-color: #f1f1f1;
        }