Bootstrap

vs

OpenUserCSS

Tailwind CSS is a customizable, low-level HTML & CSS framework. With Tailwind CSS you can create unique UIs without having to write any CSS. The framework comes with pre-written CSS classes that you can add to HTML elements to build bespoke UI components, your way.

Semantic UI is a free and open-source framework for HTML and CSS. The framework treats words and classes as exchangeable concepts. Classes use syntax from natural languages like noun/modifier relationships, word order, and plurality to link concepts intuitively. Semantic UI provides similar benefits to that of BEM or SMACSS style guidelines.

Foundation is a free and open-source HTML & CSS framework that can be used to build and design websites and web applicaitons in a structured way.

A modern responsive front-end framework based on Material Design. With Materialize CSS you can speedup your design and development process as most of the heavy lifting is done for you with default stylings that incorporate custom components. All principles of Material Design is incorporated into the framework and can be easily utilized with components and animations that provide better feedback to the users of your websites and applications.

Charts.css is a modern CSS data visualization framework. It utilizes CSS utility classes to style HTML elements as charts. Allowing developers to build interactive charts and data visualization components with CSS instead of JavaScript.

PureCSS is a free and open-source CSS framework with a minimal footprint. The entire framework and its modules weighs in at just 3.7KB minified and gzipped. With PureCSS web developers can craft responsive UI for websites that works for mobile as well as desktop. Since every line of the framework was carefully considered, you can rest assured that your page size will be kept to a minimal, and your website loads fast.