::part and ::theme, an ::explainer

Monica Dinculescu on ::part and ::theme, two pseudo-elements that are very likely to gain traction and receive more attention in the new year. They're designed to help us create and style web components, as Monica explains:

The current new proposal is ::part and ::theme, a set of pseudo-elements that allow you to style inside a shadow tree, from outside of that shadow tree. Unlike :shadow and /deep/, they dont allow you to style arbitrary elements inside a …

::part and ::theme, an ::explainer is a post from CSS-Tricks