retina-dom-to-image/spec/resources/scroll/style.css

A fork of the dom-to-image library that outputs an image for higher DPI screens

#dom-node {
    width: 50px;
    height: 50px;
    overflow: auto;
}
#scrolled {
    width: 100px;
    height: 100px;
    background-color: blue;
}