LESS is a CSS PreProcessor. LESS is a short form of CSS code. You compile the code and extract the full css code for your web page. It’s easy to maintain and you can make change is very easy. Less line by line code and code can be reused. Allow variables, mixins, functions and many other techniques that allow you to make CSS that is more maintainable, themeable and extendable.
Less runs inside Node, in the browser and inside Rhino. There are also many 3rd party tools that allow you to compile your files and watch for changes.
Get the Less from here: https://lesscss.org