| Subject: | Spaces before colons in selectors are meaningful |
Given this CSS:
#test :link, #test :visited {color: green}
The current minified CSS is:
#test:link,#test:visited{color:green}
That doesn't mean exactly the same, though - the original is "elements that are links within an element with id 'test'", while the minified only applies to an element if it has both the id 'test' and is a link.
In other words, whitespace before a colon in selectors is, sadly, meaningful (but can be collapsed to a single space).