#theme-switcher {
    position: fixed;
    top: 10px;
    right: 10px;
    opacity: 0;
    transition: opacity 0.3s;
    z-index: 1000;
    background: #fff;
    padding: 5px;
    border-radius: 4px;
    border: 1px solid #ccc;
}

#theme-switcher:hover,
#theme-switcher.active {
    opacity: 1;
}