Due to the existence of bugs in browsers' rendering engines, it is sometimes necessary to use CSS hacks to conditionally apply special styles only in specific browsers to mitigate such bugs. This repository/website houses research on some CSS hacks, including testcases and thorough compatibility test results.
For comparison, Browserhacks.com covers a greater number of hacks, including JavaScript hacks too, but as of this writing unfortunately isn't very actively maintained, and the data for a few hacks is outdated. Particularly unfortunately, there is no easy way to ascertain how up-to-date the information on each hack is. In the meantime, CSS Hacks Lab aims to be an improvement in this regard by including clear "Last updated" datestamps and by being very explicit about what browser versions have and haven't been tested.
CSS Hacks Lab is a project of the Browser Bugs Working Group.
This project is dual-licensed under the disjunction of the MIT License and the Creative Commons Attribution 4.0 International Public License.
Note that the browser logos are utilized under fair use and are not licensed. Also note that the site's theme CSS, by virtue of being a derivative work of an MIT-licensed work, is not available under the aforementioned Creative Commons license.