One of the core concepts in CSS is that of selectors. A selector determines which element(s) a CSS rule applies to. There are several ways an element can be targeted with a selector, which we will cover in this chapter.
CSS selectors can target multiple elements on the page. That is, a single CSS rule can apply to multiple elements. An element or class selector can select multiple different elements that have that class or element name.
Similarly, a single HTML element can be affected by multiple CSS rules. An element will have the properties from all applicable CSS rules applied to it.