Pseudo Elements

This pulls from the userinterface-wiki skill, specifically the CSS pseudo-elements section covering ::before, ::after, ::marker, and View Transitions API patterns. You'd use it when reviewing or generating code that uses pseudo-elements for decorative effects, hit target expansion, or native browser transitions. The guidelines are opinionated but practical, like preferring pseudo-elements over extra DOM nodes and making sure you set position: relative on parents. It's part of a larger 152-rule UI/UX system, so you're getting a slice focused on CSS implementation details rather than broader animation principles. Helpful if you want consistent pseudo-element patterns without digging through MDN every time.