Why is the em font different for different screens?

Question

Adaptive design

On a small resolution - large, and on large - small? How to set the font once for different screens so that it doesn't "run"?

Answer 1

There are several types of units of measure in CSS. Like, px, em, % and rem. There are probably more, but these are the main ones.
Moreover, there are 27-inch screens with a resolution of 1280x720 pixels. And there are screens of 27 inches with a resolution of 1920x1080. On the second, the text will be smaller than on the second simply because of the number of pixels on the screen available.
On phones, browsers usually take 1 pixel as 2-4-8 real pixels. How to "enlarge" the page for a more convenient human perception.
Related articles:
https://getinstance.info/articles/css/css-font-sizing/
https://developer.mozilla.org/ru/docs/Web/CSS/@media

Answer 2

1) use media queries in CSS for example And, yes. Not the extensions are different, but the permissions are different. The monitor has a resolution. The file has an extension. @media (max-width: 768px)