This is a test of the CSS Level 4 filter property. It works in my current versions of Firefox, Chrome and Safari. This property allows you to apply Photoshop-like filters on images or any element in the DOM.
If it is working in your browser you will see various changes to the original image (which is shown unaltered at the beginning as a point of reference).
See the Pen :matches pseudoclass by WebDevCA (@WebDevCA) on CodePen.
More information at SitePoint and Mozilla Developer Network.
