Susy
Susy: un-obtrusive grid system for designers, built on Compass and Sass
12 Alternatives To Susy
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Bootstrap
Simple and flexible HTML, CSS, and JS for popular UI components and interactions
Element UI
Element, a Vue 2.0 based component library for developers, designers and product managers.
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Foundation
The most advanced responsive front-end framework in the world
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GenesisUI
Bootstrap Admin Templates on steroids! Collection of premium bootstrap admin templates.
GroundworkCSS
Responsive HTML5, CSS and JavaScript Framework
Material Design Lite
Material Design Lite Components in HTML/CSS/JS
MediaLoot
Thousands of fonts, icons, graphics, templates, & interfaces
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Picnic CSS
Lightweight and beautiful library. Unpack your meal and start coding.
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Purecss
A set of small, responsive CSS modules that you can use in every web project.
Semantic UI
A UI Component library implemented using a set of specifications designed around natural language
Spectre
Spectre is a web application to diff screenshots.
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UIKit
A lightweight and modular front-end framework for developing fast and powerful web interfaces