html {
    --top-nav-height: 140px
}

@media screen and (min-width: 768px) {
    #top {
        height: var(--top-nav-height);
    }

    #nav-tree, #side-nav {
        height: calc(100vh - var(--top-nav-height)) !important;
    }

    #side-nav {
        top: var(--top-nav-height);
    }
}