How do people make good websites with px?

Question

This jas absolutely confused me, looking on sites. like google and creations from others, but how do they do it? You can inspect element something on a PC and it will say 100 pixels wide, than you go on a phone 300 pixels wide and it looks just as good, and how people do such great typography confuses me even more. How do they do this?

Answer 1

This is named responsive web-design

https://en.m.wikipedia.org/wiki/Responsive_web_design