Can i make responsive websites without bootstrap?

Answer 1

yes u can..
u needed firstly the viewport mtea tag
and media queries of standard CSS
and if want to use grid layouts then CSS grids as well

Answer 2

All you need for a responsive website is HTML and CSS. Bootstrap has no part in websites being responsive or not. Responsive websites are those that fit to the device’s they’re viewed on’s dimensions. Read this for more info: https://ux.stackexchange.com/questions/50499/what-is-the-meaning-of-responsive-design