@media screen and (max-width: 470px){

    /* Typography */
    [...]

    /* Countdown */
    [...]

    /* Buttons - Please add this code */
    .btn-group-alt {
        margin: 0;
    }

    .btn-group-alt .btn {
        margin: 0;
    }

    .btn-group-alt .btn:first-child {
        margin-bottom:15px;
    }

}