The Openlayers module comes with a default set of maps. It's possible to add layer templates, but it seems that the controls are always the same (see image). The controls exist of images that are located on a CDN such as http://cdnjs.cloudflare.com/ajax/libs/openlayers/2.13.1/img/zoom-plus-mini.png

Is there a way to style the controls of Openlayer maps? In other words to apply your own CSS or images to it?