.btn_quiz_controls a.disabled {
            pointer-events: none;
            cursor: default;
        }
        div#quiz_container {
            position: relative;
        }
        .lds-facebook {
            margin: auto;
            display: block;
            position: relative;
            width: 80px;
            height: 80px;
        }
        .lds-facebook div {
            display: inline-block;
            position: absolute;
            left: 8px;
            width: 16px;
            background: red;
            animation: lds-facebook 1.2s cubic-bezier(0, 0.5, 0.5, 1) infinite;
        }
        .lds-facebook div:nth-child(1) {
            left: 8px;
            animation-delay: -0.24s;
        }
        .lds-facebook div:nth-child(2) {
            left: 32px;
            animation-delay: -0.12s;
        }
        .lds-facebook div:nth-child(3) {
            left: 56px;
            animation-delay: 0;
        }
        @keyframes lds-facebook {
            0% {
                top: 8px;
                height: 64px;
            }
            50%, 100% {
                top: 24px;
                height: 32px;
            }
        }