i can't figure out way of selecting nth element, last element, or first element in cases don't know parent element. nth-child exists, children, example: <div> <p>one</p> <p>two</p> </div> p:last-child selects "two" paragraph, , p:first-child selects "one" paragraph. when have dynamic code , have no idea parent name is, or parent (may div, span, anchor, ul, etc.)? for example: <youdontknowwhat!> <p class="select-me">one</p> <p class="select-me">two</p> </youdontknowwhat!> how select second paragraph here? (i'm unable select youdontknowwhat! since don't know element (it's hypothetical name). why there first-child , last-child , , nth-child selectors , no :first , :last , :nth (like .select-me:first )? how :first different :first-child ? every html element child of other element in dom except <html> root e...