I will clone fiver, with simple SASS and without any framework.
/ | |– abstracts/ | |– variables.css # SASS Variables | |– mixins.css # SASS Mixins | |– functions.css # SASS Functions | |– placeholders.css # SASS Placeholders | |– base/ | |– reset.css # Reset/normalize | |– typography.css # Typography rules | |– base.css # Base styles | |– components/ | |– buttons.css # Buttons | |– cards.css # Cards | |– nav.css # Navigation | |– layout/ | |– header.css # Header | |– footer.css # Footer | |– sidebar.css # Sidebar | |– grid.css # Grid system | |– pages/ | |– home.css # Home specific styles | |– about.css # About specific styles | |– themes/ | |– theme.css # Default theme | |– admin.css # Admin theme | |– vendors/ | |– bootstrap.css # Bootstrap | |– jquery-ui.css # jQuery UI | |– main.css # Main SASS file