Prisma saysKnow the reference shape: properties, selectors, units, and functions — look up, don’t memorize.
CSS has hundreds of properties and many units (absolute px; relative em/rem/%/vw/vh/ch; functions like calc/clamp). Nobody memorizes it all. Know the categories and where to look (MDN). Relative units (rem, %, vw) are the backbone of responsive, accessible design.
Power-ups you unlock
Hundreds of properties — categorize, don’t memorize
Units: absolute (px) vs relative (rem, %, vw, ch)
Functions: calc, clamp, min, max, var
MDN is the canonical reference
Jank the Janitor attacks — common mistakes
Sizing everything in px (ignores zoom)
Confusing em (parent-relative) with rem (root-relative)
Reinventing values instead of checking the reference
Boss battleBuild one box using four units (px, rem, %, vw); watch each respond to resize/zoom.