Mobile-first design means building a website or app starting with phones in...

https://mike-wiki.win/index.php/How_to_Prioritize_Content_on_a_Small_Screen_Without_Cutting_Features

Mobile-first design means building a website or app starting with phones in mind. It makes pages load faster, so you don’t get stuck waiting. Buttons and links are big and easy to tap, perfect for your thumbs