Mobile Responsive

Every piece of web UI this skill touches must (1) work flawlessly from 320px to large desktop, (2) never overflow horizontally, (3) look deliberately designed, and (4) stay visually consistent with the rest of the project, both past and future.

Work mobile-first: the base, unprefixed styles target the smallest screen, then you add complexity upward. Never start from desktop and shrink down.

Step 0: Learn the project's conventions first (do not skip)

Before writing or changing any UI, read what already exists so new work blends in instead of clashing. Beautiful and consistent beats clever and isolated.