26480 2014-07-31 13:04:35 +0000 Author style max-width/height can interfere with style 2014-08-01 07:24:35 +0000 1 1 1 Unclassified WebAppsWG Fullscreen unspecified PC Linux RESOLVED FIXED P2 normal --- 1 philipj annevk bzbarsky cpearce jackalmage mike public-webapps roc public-webapps-bugzilla oldest_to_newest 109643 0 philipj 2014-07-31 13:04:35 +0000 http://fullscreen.spec.whatwg.org/#user-agent-level-style-sheet-defaults <!DOCTYPE html> <meta name="viewport" content="width=device-width"> <style> body { background: pink; margin: 0; } iframe { border: 0; height: 270px; max-height: 50%; width: 100%; } </style> <iframe src="//www.youtube.com/embed/pg5iRruqcps"></iframe> This is a minimized version of http://m.vk.com/video10345392_166569492 The author style sheet says max-height: 50% and since the user agent style sheet doesn't say differently, in fullscreen the iframe fails to fill the viewport. Unless there's some case where this makes sense, min-width, min-height, max-width and max-height should all be 100% in the UA style sheet. It fixes the problem in the wild, at least. 109648 1 annevk 2014-07-31 13:09:41 +0000 roc, WDYT? 109653 2 bzbarsky 2014-07-31 13:33:03 +0000 The Gecko styles for *|*:not(:root):-moz-full-screen are: position: fixed !important; top: 0 !important; left: 0 !important; right: 0 !important; bottom: 0 !important; z-index: 2147483647 !important; background: black; width: 100% !important; height: 100% !important; margin: 0 !important; min-width: 0 !important; max-width: none !important; min-height: 0 !important; max-height: none !important; box-sizing: border-box !important; which I suspects answers your question about what roc thinks, but also note the box-sizing and z-index bits.... 109725 3 roc 2014-07-31 23:41:21 +0000 z-index is only an artifact of the way we implement fullscreen. If we implemented it the way the spec says, with a magic extra always-on-top layer, we wouldn't need it. So I don't think that needs to be required in the UA sheet. box-sizing:border-box does need to be in the UA sheet though. 109730 4 annevk 2014-08-01 04:26:20 +0000 The specification has box-sizing. We don't have anything as !important though. Wouldn't we want to let developers override these things? 109731 5 annevk 2014-08-01 04:26:58 +0000 Also, does the CSS specification even allow !important for user agent style sheets? 109735 6 philipj 2014-08-01 06:55:06 +0000 Blink also has !important sprinkled all over its fullscreen.css UA style sheet, FWIW. 109737 7 annevk 2014-08-01 07:10:23 +0000 It seems per http://dev.w3.org/csswg/css-cascade/ user agent style sheets can do this. Okay. 109739 8 annevk 2014-08-01 07:24:35 +0000 https://github.com/whatwg/fullscreen/commit/134cdeb6d6d3f7c3bdb3c9df754185c24a59353f