tinymighty / booty

A modern theme for MediaWiki, built on Bootystrap 3 and Skinny.
MIT License
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Issue with media queries in CSS #4

Open andru opened 10 years ago

andru commented 10 years ago

Reported by Daniel....

I had to comment out a few lines of core MediaWiki code to get bootstrap to work with IE, even IE 11. It appears that ResourceLoader does some strange stuff, and I am not sure if this is a bug in Skinny/Booty or just a bad idea in the way the MediaWiki devs are handling CSS resources.

Here, in a nutshell, is the issue.

ResourceLoader.php has a function called makeCombinedStyles() that merges CSS files into one big glob. And if the CSS file are intended for "screen" display, it wraps all of the CSS definitions in a media query, like this:

"@media screen {" + all_my_css +"}"

For most browsers, this is not a problem. However, IE, even the most recent versions of IE, do not support nested media queries, so this doesn't work:

"@media screen { @media foo { } }"

So, if your CSS already has media queries in it, then the act of makeCombinedStyles() wrapping the CSS in a media query actually breaks the CSS for all versions of IE, because it turns all of bootstrap's intentionally non-nested media queries into nested media queries, which IE then ignores.

There are some workarounds:

1) Make sure the CSS resource has a media value of '' or 'all' -- that way, it is not wrapped in a media query when makeCombinedStyles() is called. 2) Comment out the core MediaWiki CSS code that wraps 'screen' resources in a media query.

I am not sure what the "right" solution is. If we should expect ResourceLoader.php to be able to serve arbitrary CSS and have it work in all browsers, then it is simply not okay to wrap the CSS in a media query.

If the current MediaWiki behavior is the "correct" behavior, then any CSS marked for "screen" display must not have embedded media queries, or it will end up broken for all IE users.

I am not sure if this is a MediaWiki bug/oversight or a Booty/Skinny bug, so I wanted to get your opinion on it.