#installer {
    position: fixed;
    opacity: 0;
    bottom: 0;
    left: 0;
    text-align: center;
    transition: opacity 300ms ease-in-out;
}

#installer.available {
    opacity: 1;
}

#installer .button {
    border: white 1px solid;
    margin:10px;
    padding: 10px;
    color: white;
    background-color: transparent;
}