:root {
    --header-height: 154px;
    --body-border: 5px; /* no idea why there is a 5px border on the body */
}

main {
    padding-top: calc(var(--header-height) - var(--body-border));
}

.site-header {
    position: fixed;
    width: 100%;
    top: 0;
    left: 0;
    z-index: 10;
    transition: top 0.2s ease-in-out;
    background-color: #fff;
}

.site-header--nav-up {
    top: calc(var(--header-height) * -1);
}