CSS files, that load in html <head> section of page in the current template are the
following:
<! - Theme Styles CSS -><link rel = "stylesheet" type = "text / css" href = "css / vendors / Bootstrap / bootstrap.min.css"><link rel = "stylesheet" type = "text / css" href = "css / vendors / Bootstrap / bootstrap-grid.min.css"><link href = "css / plugins / navigation.min.css" rel = "stylesheet"><link rel = "stylesheet" type = "text / css" href = "css / main.min.css"><link rel = "stylesheet" type = "text / css" href = "css / theme-font.min.css">
bootstrap.min.css - bootstrap styles
bootstrap-grid.min.css - bootstrap modular grid styles
navigation.min.css - styles of the main menu (navigation)
main.min.css - main site's stylesheet;
theme-font.min.css - font styles of the template.
IMPORTANT: if necessary, in the HTML/css folder you can find the non-minified style files and use them.