Main css template(s)

Hi folks,
For customizing conferences Indico provides an example of a css style sheet through ~/css/confTemplates/standard.css. Is there a similar example to customize the whole Indico site? is there a repo where people share their css files? Or, in alternative, can someone provide such an example and/or her/his css file(s)?

Using the browser’s dev tools is painful and extremely time-consuming (and not leading me very far), at least for people like me who are not proficient with css.