Yes you can! Just tested this and it works great, this is awesome!
#test::before {
content: url(path/to/your.svg);
width: 200px;
height: 200px;
}
Or if you prefer to put the SVG directly in the CSS:
#test::before {
content: url("data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg"%3E%3Ccircle cx='100' cy='50' r="40" stroke="black" stroke-width="2" fill="red"/%3E%3Cpolyline points="20,20 40,25 60,40 80,120 120,140 200,180" style="fill:none;stroke:black;stroke-width:3"/%3E%3C/svg%3E ");
width: 200px;
height: 200px;
}
<div id="test"></div>
SVG URL encoder to format your own SVGs as shown here.