USS Breakpoints

Hi, is there any information about doing breakpoints for USS? For example like Bootstrap guys are doing it when the width gets lower than a certain amount, a class is applied. When the class make elements removed/etc. then the flex box automatically handles the rest.

For example a slider with number at the end could be just a slider when the width is not large enough instead of having to planning the flex-grow to push the unneeded things overflow out of the edge.