Codebase

Global and local styling

Simple.css - A classless CSS framework

Superkube

ChartsCSS/charts.css

Skeleton: Responsive CSS Boilerplate

daveberning/griddle: A CSS Grid Framework

new.css

mono/color

Halfmoon - Front-end framework with a built-in dark mode and full customizability using CSS variables; great for building dashboards and tools

Cirrus - Typography

MVP.css - Minimalist stylesheet for HTML elements

turretcss - A Responsive Front-end Framework for Accessible and Semantic Websites

Spectre.css CSS Framework

UIkit

TACHYONS - Css Toolkit

Knopf.css - Open source button system leveraging CSS variables

holiday.css - a minimalist classless CSS theme

Milligram - A minimalist CSS framework.

swlkr/ridgecss

Basscss

Documentation - Materialize

kognise/water.css

Bulma: Free, open source, & modern CSS framework based on Flexbox

MUI - Material Design CSS Framework

DesignRevision - Free & Premium Bootstrap Templates and Themes