What are the three CSS-wide keywords (values) and what do they do?

  • Keyword: initial

The initial CSS keyword applies the initial (or default) value of a property to an element. It can be applied to any CSS property. This includes the CSS shorthand all, with which initial can be used to restore all CSS properties to their initial state.

  • Keyword: inherit

The inherit CSS keyword causes the element for which it is specified to take the computed value of the property from its parent element. It can be applied to any CSS property, including all the CSS shorthands.

For inherited properties, this reinforces the default behavior, and is only needed to override another rule.

  • Keyword: unset

The unset CSS keyword resets a property to its inherited value if the property naturally inherits from its parent, and to its initial value if not. In other words, it behaves like the inherit keyword in the first case, when the property is an inherited property, and like the initial keyword in the second case, when the property is a non-inherited property.