LESS is open-source. Its first version was written in Ruby, however in the later versions, use of Ruby has been deprecated and replaced by JavaScript. The indented syntax of Less is a nested metalanguage, as valid CSS is valid Less code with the same semantics.
LESS provides the following mechanisms: variables, nesting, mixins, operators and functions.LESS can run on the client-side (Internet Explorer 6+, WebKit, Firefox) and server-side, with Node.js or Rhino (JavaScript engine).
