Google's John Mueller was asked if Google "looks at "CSS .Class" to comprehend the structure of a page; or a section of content that clarifies its SERP Features." John responded on Twitter saying ...

e1 > e2 -- (immediate decendant selector) selcts e2 in the case e1 is its parent. e1 + e2 -- (adjacent sibling selector) selects e2 when it directly follows e1 and e1&e2 have a common parent.