SonarSource provides a static code analyzer for CSS. Based on our own CSS analyzer, it can find bugs, security vulnerabilities and code smells. As for any product we develop at SonarSource, it was built on the following principles: depth, accuracy and speed.
SonarCSS has a great coverage of well-established quality standards. The SonarCSS capability is available throughout the development chain for automated code review with self-hosted SonarQube or on-line SonarCloud.