Test information available from the nightly build of the CSS 2.1 Test Suite.
Gecko test details
9251 pass, 249 fail, 6 untested
Adjacent sibling selectors have the following syntax: E1 + E2, where E2 is the subject of the selector. The selector matches if E1 and E2 share the same parent in the document tree and E1 immediately precedes E2, ignoring non-element nodes (such as text nodes and comments).
Thus, the following rule states that when a P element immediately follows a MATH element, it should not be indented:
math + p { text-indent: 0 }
The next example reduces the vertical space separating an H1 and an H2 that immediately follows it:
h1 + h2 { margin-top: -5mm }
The following rule is similar to the one in the previous example, except that it adds a class selector. Thus, special formatting only occurs when H1 has class="opener":
h1.opener + h2 { margin-top: -5mm }
Adjacent sibling selectors have the following syntax: E1 + E2, where E2 is the subject of the selector. The selector matches if E1 and E2 share the same parent in the document tree and E1 immediately precedes E2, ignoring non-element nodes (such as text nodes and comments).
Thus, the following rule states that when a P element immediately follows a MATH element, it should not be indented:
6 untested, please test
math + p { text-indent: 0 }
The next example reduces the vertical space separating an H1 and an H2 that immediately follows it:
h1 + h2 { margin-top: -5mm }
The following rule is similar to the one in the previous example, except that it adds a class selector. Thus, special formatting only occurs when H1 has class="opener":
h1.opener + h2 { margin-top: -5mm }