topnav {
    position: sticky;
    width: 100%;
    top: 0;
    background-color: #111;
    display: flex;
    justify-content: space-around;
    user-select: none;
    font-size: large;
    padding: 1vh 0;
    color: white;
    z-index: 10;
    white-space: nowrap;
}

topnav a {
    cursor: pointer;
    color: white;
    text-decoration: none;
    transition: all 150ms;
    border: 1px solid #111;
    padding: 1vw 1vw;
}

topnav a:hover {
    color: #aaa;
    border: 1px solid #aaa;
}

@media (max-aspect-ratio: 1/1) {
    topnav {
        display: none;
    }
}