The most important rule, as far as CSS Lint is concerned, is to ensure there are no parsing errors in the CSS. Parsing errors usually mean you mistyped a character and caused the code to become invalid CSS. These errors may cause the browser to drop a property or an entire rule. Parsing errors are always presented as errors by CSSLint, the most important issues to fix.
The following rules point out potential errors in your CSS.
The following rules flag for compatibility problems across browsers and browser settings.
The following rules are aimed at improving CSS performance, including runtime performance and overall code size.
These rules help to ensure your code is readable and maintainable by others.
These rules are designed to pick out possible accessibility issues.
These rules are based on the principles of OOCSS.