If you can devote all of your weekends in a month into engineering CSS3 and the structural nature of XF2 default templates, then you might not need a framework to do it.which framework has used for xenforo responsive design
for example if i want to edit responsive theme or making new theme which framework i should know?
this is different question and also at this time i didn't get my answer by a simple knowledge i can make a whole theme?!!Pretty much the same answers as you received here, https://xenforo.com/community/threads/program-language-for-front-end.179536/
I forgot to say one more language, still:You need to know the previous mentioned programming languages and familiarize yourself with the template syntax.