Mobile-first design means creating apps and websites that work best on your...

https://www.newpelican.com/articles/why-mobile-first-design-has-become-the-standard-for-modern-digital-services/

Mobile-first design means creating apps and websites that work best on your phone. It focuses on speed, making sure pages load fast so you don’t wait around. Buttons and links are big and easy to tap with your finger