CSS has a simple syntax and uses a number of English keywords to specify the names of various style properties.
A style sheet consists of a list of rules. Each rule or rule-set consists of one or more selectors and a declaration block. A declaration block consists of a list of semicolon-separated declarations in braces. Each declaration itself consists of a property, a colon (:), a value, and a semicolon (;).
In CSS, selectors are used to declare which elements a style applies to. Selectors may apply to all elements of a specific type or only to those elements that match a certain attribute. Elements may be matched depending on how they are placed relative to each other in the markup code, or on how they are nested within DOM.