How to properly use bootstrap responsiveness?

Question

css

To be honest, I could not compose a short and understandable question.
Started getting familiar with bootstrap. I'm trying to use responsive layout - columns. If when you change the screen, you only need to adjust the width of the element, then everything is fine. But what if you need, say, to measure the indents (padding or margin)? Or font size?
Start another section with media queries?

Answer 1

Yes. It's made that way from the inside.
Grab the less version from github and see how it works. It will immediately become clear.
On less and build the layout, so a bunch of goodies.

Answer 2

don't mess with the framework code. get yourself a new file. not for nothing that bootstrap gives us bootstrap-theme.less hinting that reassign everything else here