Selectors.
Type selectors:-Any CSS applied to particular element would be applied to all the occurences of that element.
Class selectors:-Elements in classes with same value allows a common set of CSS rules to be applied to the whole selestion of elements.
Id selectors:- Allows elements to be uniquely selected for any CSS rules to be applied.
Psuedo selectors:-
selectors combination:- Can select element that is a child of another element.