body {
    margin: 0;
    padding: 0;
    font-family: sans-serif;
}
main {
    padding-top: 70px;
}

#page-top {
    position: fixed;

    right: 30px;
    bottom: 30px;

    width: 50px;
    height: 50px;

    border: none;
    border-radius: 50%;

    background-color: #60ac4f;
    color: white;

    font-size: 20px;
    cursor: pointer;

    display: none;

    z-index: 999;

    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

#page-top:hover {
    opacity: 0.8;
}