Animation in pseudo-element

dabblet.css

/**
 * Animation in pseudo-element
 */
div { 
height: 100px;
background: #eee;
}
div:before {
content:" ";
display:inline-block;
width: 200px; height: 100px;
background: #fff;
vertical-align: middle;
transition: width 1s;
}
div:hover:before {
width: 240px;
}

dabblet.html

<div>Hello World!</div>

settings.json

{"view":"split","prefixfree":"1","page":"css"}