This 9-minute video from Juxtopposed on blurring is a great watch. There are an awful lot of ways to blur things on the web, from filter, backdrop-filter, <feGaussianBlur>, to WebGL. I particularly like the idea of masking an element with a backdrop-filter with a gradient so, for instance, a header can fade out how much blur is being applied.
Featured
Staggered Animation with CSS sibling-* Functions
The new CSS sibling-index() (and -count()) functions are perfect for staggered timing affects. This goes a little step further staggering both before and after a selected element.