A mobile-first approach in design prioritizes the development of websites or applications for mobile devices before desktop versions. This strategy recognizes the growing prevalence of mobile browsing and allows for an optimized user experience on smaller screens. Benefits include improved performance, enhanced user engagement, and better accessibility. Additionally, it encourages developers to focus on essential features, reducing clutter and increasing usability. Overall, adopting a mobile-first mindset leads to more responsive designs that cater to the needs of users accessing content on the go.