In the past, I've used CSS hacks
_ as a quick and dirty way to make a few CSS changes for IE6 and IE7 only , while preferring conditional comments for larger scale adjustments.
When IE8 came out, developers used another CSS hack (
\9;) to target just IE8. But when IE9 came out, it also rendered
\9; hacks, which made it
the perfect example of an unsafe CSS hack.
Since then, things have only gotten messier for CSS hacks. There are tons of new browsers out there, and IE10 was the last IE to support conditional comments. While CSS selectors still remain fairly ugly, sometimes they're just the tool you need. Fortunately, Browserhacks has pulled all the hacks from all over the internet into one place. And it's on GitHub - so you can add to it.