Mobile-first design means building websites and apps to work great on phones...

https://www.save-bookmarks.win/mobile-first-design-means-creating-apps-and-websites-that-work-great-on-your

Mobile-first design means building websites and apps to work great on phones first. It focuses on fast loading, easy-to-tap buttons, and simple menus that fit small screens. This makes browsing quick and smooth, even on the go