The document describes the CSS structure for an education application called InterSIS. It shows the folder structure for stylesheets, with main files like application.css and modules/_all.scss. Entries are the main style files for each page. Partials contain shared and page-specific styles. The entry for the student profile page is _student_profile.css. It also discusses using Ruby on Rails helpers and a grid system for layout. Examples demonstrate integrating styles into views. The document warns against bad practices like duplicating styles.