#topBtn {
        position: fixed;
        line-height: 1;
        border:none;
        bottom: 20px;
        right: 20px;
        border-radius: 999px;
        width: 3rem;
        height: 3rem;
        background: rgb(70,70,70);
        display: none;
        align-items: center;
        justify-content: center;
        opacity: 0.5;
        z-index:99;
        &:hover {
            opacity: 1;
        }
        & svg {
            fill: white;
            width:2rem;
            height:2rem;
        }
    }

#topBtn.show {
    display: flex;
}