The <number>CSS data type represents a number, either integer or fractional. Its syntax extends the one of the <integer> data value. To represent a fractional value, add the fractional part — a '.' followed by one or several decimal digits — to any <integer> data value. Like for <integer> data type, there isn't any unit associated to a <number>, which is not a CSS dimension.
The <time>CSS data type denotes time dimensions expressed in seconds or milliseconds. They consists of a <number> immediately followed by the unit. Like for any CSS dimension, there is no space between the unit literal and the number.
The unset CSS keyword is the combination of the initial and inherit keywords. Like these two other CSS-wide keywords, it can be applied to any CSS property, including the CSS shorthand all. This keyword resets the property to its inherited value if it inherits from its parent or to its initial value if not. In other words, it behaves like the inherit keyword in the first case and like the initial keyword in the second case.
The @font-faceCSSat-rule allows authors to specify online fonts to display text on their web pages. By allowing authors to provide their own fonts, @font-face eliminates the need to depend on the limited number of fonts users have installed on their computers. The @font-face at-rule may be used not only at the top level of a CSS, but also inside any CSS conditional-group at-rule.