Very simple site – Homepage & text area stuff

Hi,

All that is kind of new for me bu it may be easy for someone who know what he’s doing.

I understood the theme i use has a “Homepage” that hasnt the same code than the others ( Text area is larger, padding are diferent …) but i can’t find where it come from (the diference).

Also, I don’t know how to set a larger text area (.content?), same for this homepage and the others pages.

So my problem is :
-> how can i set the homepage to be as the others,
-> how can i change the width of the text area, without hurting the phone/tablet compatibility.

Thanks a lot for your participation !

ps: sorry for my english, i get better everyday.