Answer
Mobile-first CSS starts with styles for constrained viewports and adds enhancements for larger spaces. • Base rules work without a minimum-width query. • min-width media queries add layout complexity as room becomes available. • The approach does not mean ignoring desktop users.
💡 Simple Example
.nav { display: block; }
@media (width >= 48rem) { .nav { display: flex; } }
⚡ Quick Revision
Mobile-first starts simple and enhances with min-width queries.