Tweening gradients in CSS is easy. In canvas its a little harder. This sample uses the TweenJS ColorFilter to tween colors, and then applies them as a gradient to get the desired effect
Some op art for fun. Reproducing oldschool c64 raster effects with css gradients and animation, then taking it a bit further.
Stroke with linear-gradient
Not tested on 'Safari'. :)
Animated and expandable gradient sidebar created with React and SCSS.