This report was prepared to document the current implementation status of the CSS Basic User Interface Module Level 3 (CSS User Interface 3) specification as of 23 October 2017 and is based on current test results available in the W3C Conformance Test Harness.
Eight user agents, built from five rendering implementations, were tested across five operating systems.
The 23 October 2017 revision of the CSS User Interface 3 test suite was used. The test suite consists of 234 tests, 31 of which test for optional behavior.
These tests are available in several host language variants:
Some tests only apply to certain language variants; the results for each tested implementation are reported for each tested language variant. Also, not all tests are applicable to each implementation; for example, a browser which implements HTML but not XHTML is not tested for XHTML.
In summary, the results show that all 203 tests for required behavior were passed by at least two of the tested implementations. In addition, 11 of 31 tests for optional behavior were passed by at least two of the tested implementations.
Results were gathered from implementation reports submitted by user agent vendors as well as the general public via the W3C Conformance Test Harness.