Check your CSS code without leaving the IDE by using CssCop, which brings the CSS Lint functionality to the Visual Studio environment.

Simplest tip ever: Use Visual Studio's Go To Definition with CSS classes to get from your HTML to the relevant CSS rule. First click on the name of a class in your HTML ...

It is also available for Mac, which makes it easy to deal with HTML/JS/CSS, i.e. client-side technologies. Most developers using Windows and developing for Windows will use Visual Studio IDE ...