div.up {
    background-color: #434362;
    width: 50px;
    height: 50px;
    border-radius: 60px;
    transition: transform 0.25s ease, opacity 0.25s ease;

    position: fixed;
    right: 0px;
    bottom: 0px;
    z-index: 10;
    margin: 35px;
    display: none;
}

div.up img {
    width: 100%;
    height: auto;
}

div.up.show {
    display: block;
    opacity: 1;
    transform: scale(1);
}

div.up:hover {
    transform: scale(1.1);
    cursor: pointer;
}