The holmes.css is useful for checking the quality of your code (up to W3C HTML5 standards), nitpicking over ensuring markup is valid and semantic and accessility guidelines are met, and when you are tasked to fix up and debug an old, OLD website.

The holmes.css file will display either an error (red outline), a warning (yellow outline), or a deprecated style (dark grey outline) for flags such as: Missing required attributes on tags, Potentially improvable markup, Deprecated and Non-W3C Elements and Non-W3C Attributes.

Requirements: -
Demo: http://www.red-root.com/sandbox/holmes/
License: License Free