.header {

    position: absolute;

    width: 100vw;

    height: 4rem;

    display: flex;

    align-items: center;

    justify-content: center;

    z-index: 1;

}



.header a div {

    height: 1.5rem;

    opacity: .7;

    font-size: min(3.5vw, 1rem);

    border-bottom: 2px solid transparent;

    transition-duration: 250ms;

}



.header a div:hover, .header a div:active {

    border-bottom: 1px solid #eee;

}