LESS : Less is a CSS pre-processor, meaning that it extends the CSS language, adding features that allow variables, mixins, functions and many other techniques that allow you to make CSS that is more maintainable, themable and extendable.
SASS : Sass is the most mature, stable, and powerful professional grade CSS extension language in the world.
Framework
Front-end Frameworks : A collection of best front-end frameworks for faster and easier web development.
BootStrap : Bootstrap is the most popular HTML, CSS, and JS framework for developing responsive, mobile first projects on the web.
Foundation : The most advanced responsive front-end framework in the world.
Semantic UI : Semantic is a UI component framework based around useful principles from natural language.
Normalize.css : A modern, HTML5-ready alternative to CSS resets
Cutestrap : A sassy, opinionated CSS Framework. A tiny alternative to Bootstrap.
Pure.CSS : A set of small, responsive CSS modules that you can use in every web project.
uikit : A lightweight and modular front-end framework
for developing fast and powerful web interfaces.
Material-UI : A Set of React Components that Implement Google's Material Design
Materialize : A modern responsive front-end framework based on Material Design
Material framework : Material Framework is a simple responsive CSS framework made by Tim Nguyen that allows you to integrate Material Design in any web page or web app.
Leaf : A CSS framework based on Google's material design
Simple : Minimal CSS framework for flat and clean designs.
Unique gradient generator : This tool helps you to generate beautiful blurry background images that you can use in any project. It doesn't use CSS3 gradients, but a rather unique approach. It takes a stock image, extracts a very small area (sample area) and scales it up to 100%. The browser's image smoothing algorithm takes care of the rest.
CSS Peeper : Smart CSS viewer tailored for Designers
Google Web Designer: Create engaging, interactive HTML5-based designs and motion graphics that can run on any device.
JS库
JSpreadSheets : JavaScript Open-Source Spreadsheets and Data Grids