LESS is a dynamic stylesheet language designed by Alexis Sellier. It is influenced by Sass and has influenced the newer "SCSS" syntax of Sass, which adapted its CSS-like block formatting syntax.

LESS is open-source. Its first version was written in Ruby,

We are happy to announce Bootstrap, a front-end toolkit for rapidly developing web applications. It is a collection of CSS and HTML conventions. It uses some of the latest browser techniques to provide you with stylish typography, forms, buttons, tables, grids, navigation andeverything else you need