HTML and CSS Reference
Chapter 2. Values
There are a variety of value types in CSS, most of which use units. Combining basic value
types (such as numbers) with units (such as pixels) makes it possible to do any number of in-
teresting things with CSS.
Keywords are defined on a per-property basis and have a meaning specific only to a given
property. For example, normal has totally unique meanings for the properties font-variant
and letter-spacing . Keywords, like property names, are not case-sensitive. A special case
is the keyword inherit , which is allowed on all properties and always has the same meaning
(get the associated property's value from the element's parent). There is a second special uni-
versal keyword, initial , which is meant to represent the initial or default value for a given
property. Thus, declaring font-family: initial would return the browser's preferences-
based default font family. (Times, for most people.) The status and application of initial is
unclear as of this writing and may be unreliable.