All HTML Templates has one main file of styles called style.css.
CSS Code for the mobile devices, and some fix for desctop/mobile devices you may see in other file called responsive.css or this code inluded in style.css
Main file of CSS code – style.css include content, so you could quickly navigate.
It looks like this:
style.css – the main file to change the appearance of the template. To have all of your actions have been applied styles write your code (if necessary) in this section:
/* Your CSS Code */, after that comment, that is at the end of the CSS file.