Styles
Typed CSS-ish styles, checked at compile time, plus things CSS doesn't have.
A typo in a property or value is a compile error with the list of what is accepted. when covers hover, focus, active, dark, light, reduced-motion, viewport and container sizes, and appear for scroll reveals.
Beyond CSS
corner: squircle | cut | scoop | round: the shape of rounded corners, and everything (borders, shadows, clipping) follows it.
grain: 0.4: film grain, because your landing page needed to feel more analog.
sketch: 2px #222: hand-drawn, wobbly borders that stay still between frames.
spring and bounce easings: transition: transform 500ms spring.
Fonts
Ship a font file from public/, or take one from Google Fonts. Styles then use the family by name: font: "Space Grotesk", sans-serif.