[sibling-function-if-style-query.html]
  [sibling-index() in an if() style() comparison]
    expected: FAIL

  [sibling-index() inside mod() in an if() style() comparison]
    expected: FAIL

  [sibling-index() compared against a registered custom property]
    expected: FAIL

  [sibling-count() in an if() style() comparison]
    expected: FAIL