#sfs-button {
    position: fixed;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    cursor: pointer;
    border: none;
    opacity: 0;
    pointer-events: none;
    transition: opacity .25s ease, transform .25s ease;
    z-index: 9999;
}

#sfs-button.show {
    opacity: 1;
    pointer-events: auto;
}

#sfs-button:hover {
    transform: scale(1.08);
}

.sfs-icon {
    font-size: 18px;
    line-height: 1;
}

/* Positions */
body[data-sfs-pos="right-bottom"] #sfs-button {
    right: 20px;
    bottom: 20px;
}
body[data-sfs-pos="left-bottom"] #sfs-button {
    left: 20px;
    bottom: 20px;
}
body[data-sfs-pos="top-right"] #sfs-button {
    right: 20px;
    top: 20px;
}
body[data-sfs-pos="top-left"] #sfs-button {
    left: 20px;
    top: 20px;
}