Tests the language selectors, :lang(c).
Note that a less specific language (such as fr) also matches a more specific language (such as fr-CA) but a more specific language (such as en-GB) does not match a less specific language (such as en). Also note that language tags,and thus language selectors are case-insensitive.
Run the test. No interaction required.
The phrase "Good morning!" should be in green. The phrase "Bon avant-midi!" should be in blue; in addition, the "avant-midi" should be italic because its Canadian French.