:root {
    --smaller: .75;
}


/*.container {*/
/*    color: #333;*/
/*    margin: 0 auto;*/
/*    text-align: center;*/
/*}*/

.countdown li {
    display: inline-block;
    font-size: 1.5em;
    list-style-type: none;
    padding: 1em;
    text-transform: uppercase;
}

.countdown li span {
    display: block;
    font-size: 3rem;
}

@media all and (max-width: 768px) {
    .countdown li {
        font-size: calc(1.125rem * var(--smaller));
    }

    .countdown li span {
        font-size: calc(3.375rem * var(--smaller));
    }
}