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 ...

Also in Visual Studio Code 1.66, the built-in CSS extension now ships with a code formatter, implemented by the js-beautify library, that works with CSS, LESS, and CSS.