body{
    margin:0;
    background:#000000;
    font-family:Arial;
}

#toolbar{
    position:fixed;
    top:0;
    width:100%;
    background:#000;
    padding:10px;
    text-align:center;
}

#viewer{
    margin-top:60px;
    display:flex;
    flex-direction:column;
    align-items:center;
}

.page{
    position:relative;
    margin-bottom:40px;
}

canvas{
    filter: invert(1) hue-rotate(180deg);
}