How to make two versions of html / css code display, desktop and mobile devices?

Question

css

Wrote responsive html/css, but it's hard to read in the mobile version, you have to zoom in. What and how to enter in order to display briefly written text instead of all html when opened on a mobile device.
*html/css in one .html file
Thanks!

Answer 1

Good afternoon.
I always dump these things on Bootstrap.
Once it also hid the blocks, now the framework itself neatly places them on any platform.
On the question of how to hide - bootstrap-4.ru/docs/4.1/utilities/display

Answer 2

With the help of media queries on the resolution of mobile devices, increase the font size and generally fit everything you need.

Answer 3

Agree with previous comment. Viewport 1. Next, media queries specify what will happen with a certain range of pixels of the browser window width.