A design approach that starts with the mobile experience and progressively enhances for larger screens. Mobile-first forces prioritization and ensures the smallest screens get the best experience, not a squeezed afterthought. This approach often results in cleaner, more focused designs at all screen sizes.

A CSS unit equal to 1% of the browser viewport width, enabling fluid sizing relative to screen width. Vw units are useful for responsive typography and full-width elements. Combine with max-width constraints for practical maximum sizes. See Relative, fixed, and viewport Sizing in Framer.

The horizontal measurement of an element, definable as fixed pixels, percentages, or content-based sizing. Responsive designs often use percentage or max-width rather than fixed widths for flexibility. Framer's sizing controls support fixed, relative, and content-based width options.

The point at which content becomes hidden until the user scrolls, varying by device and browser window size. The fold isn't fixed—a laptop, phone, and tablet all have different fold positions for the same page. Design for common viewport sizes while ensuring content below the fold is still discoverable and engaging.

The positioning of elements relative to each other or a container to create visual order and clarity. Strong alignment improves scanability and perceived quality. In Framer, layoutauto layout and constraints help maintain consistent alignment across breakpoints.

AGENTS.md is a project instruction file that gives AI coding agents task context, workflow rules, and constraints so agent behavior aligns with team standards.