Mobile-first means writing your base CSS for small screens, then layering on styles for larger ones with min-width media queries. You build up from a lean foundation instead of stripping a heavy desktop layout down. This cheatsheet gathers the core patterns on one page, each snippet annotated line by line. Keep it open while you build, or save the image and pin it nearby.
For the full background, read why you should design for mobile-first.
[…] Mobile-First Design Cheatsheet […]