There are two things you always have to do when building a website or web application: use a CSS preprocessor and bundle and minify your style/script resources. Using a preprocessor makes writing CSS not so horrible and bundling and minification gives you great performance advantages when you minimize your request amount and size.
Bundling and minification is usually done with grunt or gulp.js but in .NET environment you can take advantage of Microsoft ASP.NET Web Optimization Framework.

This guide will tell you how to use LESS as the CSS preprocessor along with bootstrap‘s LESS source and .NET bundling and minification. Read more…