@import url('https://fonts.googleapis.com/css2?family=Yusei+Magic&display=swap');
html {
    font-size: calc((100vw - 320px) / 140 + 16px);
}

.center-parent {
    position: fixed;
    width: 100vw;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
}

.center-child {
    font-size: 4em;
    font-family: 'Yusei Magic', sans-serif;
    display:inline-block;
    padding:10px;
}