#arrow-up {
    position: fixed;
    bottom: 50px;
    right: -50px;
    text-decoration: none;
    width: 50px;
    height: 50px;
    background: rgb(2, 0, 36);
    background: linear-gradient(
        90deg,
        rgba(2, 0, 36, 1) 0%,
        rgba(0, 0, 0, 1) 100%
    );
    color: white;
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    border: 1px white solid;
    opacity: 0;
    transition: opacity 0.5s;
    z-index: 996;
}

#arrow-up.show {
    right: 50px;
    opacity: 1;
    transition: opacity 0.5s;
}

@media (max-width: 500px) {
    #arrow-up {
        bottom: 25px;
    }

    #arrow-up.show {
        right: 25px;
    }
}