CSS3

One of the interesting things about Acid 3 is that it tests parts of the CSS3 Colour and CSS3 Selectors modules, that are a part of the 2007 CSS snapshot. Now that both Opera and WebKit pass the standards part of the Acid 3 test, the support for the snapshot has now also improved. The CSS 2007 snapshot is the state of play in CSS at the end of 2007.

WebKit used to lack support for many CSS3 selectors, but now passes the CSS3 Selectors test on this site, and supports all of these selectors. Opera already supported these, but didn’t support HSLA, RGBA and the CSS3 values for transparent. These were added to pass Acid 3 in a post Kestrel build (which may or may not be back ported). Due to these improvements, support in these two browsers for the CSS 2007 snapshot looks healthy.

Ignoring CSS2.1 for now (which Opera has very good support for), both browsers fully support the Selectors Level 3 spec and the CSS Namespaces spec. For CSS3 Colour, the support isn’t quite as clear cut. Everything is supported in Opera, except the flavor keyword and the various related colour profile properties. These properties are at risk of being dropped by the spec however. WebKit has the same support except it doesn’t support currentColor yet, and has some bugs with allowing mixed values in RGB and RGBA. Firefox has had similar CSS3 Colour support to Opera for a while now

Away from the 2007 snapshot, ACID3 also tests Media Queries. These were already supported in Opera and WebKit, but are not yet supported in Gecko or the IE engine. Web Fonts (@font-face) are in the test and were already supported by WebKit, while Opera was developing support, but speeded up development to pass the test. Finally cursor from CSS3 Basic User Interface was added by Opera to pass Acid 3. I’m unsure if this was already supported by WebKit or not.

Although CSS3 UI is not part of the CSS 2007 snapshot, the spec is close to being complete–apart from lacking an editor or a test suite–and support in one or more browsers exists for many of the properties. The features supported by one or more browsers now includes box-sizing (Opera, Safari, Firefox and IE8), resize (Safari), outline-offset (Opera, Safari and Firefox), nav-up, nav-down, nav-right and nav-left (Opera) and cursor (Opera, Safari and Firefox).