Rulesets #

A ruleset consists of a selector (or a group of selectors) paired with a declaration block.

A declaration block {} contains one or more declarations.

A declaration Property: Value; sets a value for a property.

Declarations must end with a semicolon, except for the last one. Adding a semicolon to it is recommended, though.

CSS
* {
  box-sizing: border-box;
}

h1,
h2 {
  color: black;
  font-weight: bold;
  font-size: 3rem;
}