:root {

    --var-fs: 0.75vw;
    font-size: var(--var-fs);
}

@media screen and (max-width: 1279px) {
    :root {
        --var-fs: 1.5vw;
    }
}

@media screen and (max-width: 767px) {
    :root {
        --var-fs: 2vw;
    }
}

@media screen and (max-width: 639px) {
    :root {
        --var-fs: 2.75vw;
    }
}

* {
    box-sizing: border-box;
    padding: 0;
    margin: 0;
}