comma (,)[css selector: h1, h2, h3, h4, h5, h6]
Groups of selectors on one rule
Descendant Selector ( space ) [ #myList ol li ]Decedent Selectors allow you to apply styles to elements that are contained within another.
Ways to Apply CSS
Child Selector (>) [ div > p ]If you want to choose only direct children, we can use the child selector with the greater than symbol (>). This selects child elements that are directly under the parent element.
Second Hello Mars!
Adjacent Sibling Selector (+) [ #sibling3+li ]Sibling elements are those that have the same parent, and adjacent siblings are those that are right next to each other.
General Sibling Selector (~) [ #sibling22~li ]To broaden our scope to all siblings proceeding the selection, we use a tilde (~). This will select all elements that are of a sibling that come after the selected item.
CSS Specificity Hierarchyhttps://www.w3schools.com/css/css_specificity.asp