Font properties

font-size
Value: <absolute-size> | <relative-size> | <length> | <percentage>
Initial: medium
Applies to: all elements
Inherited: yes
Percentage values: relative to parent element's font size

<absolute-size>
An <absolute-size> keyword is an index to a table of font sizes computed and kept by the browser. Possible values are: [ xx-small | x-small | small | medium | large | x-large | xx-large ]. On a computer screen a scaling factor of 1.5 is suggested between adjacent indexes; if the 'medium' font is 10pt, the 'large' font could be 15pt. Different media may need different scaling factors. Also, the UA should take the quality and availability of fonts into account when computing the table. The table may be different from one font family to another.

<relative-size>
A <relative-size> keyword is interpreted relative to the table of font sizes and the font size of the parent element. Possible values are: [ larger | smaller ]. For example, if the parent element has a font size of 'medium', a value of 'larger' will make the font size of the current element be 'large'. If the parent element's size is not close to a table entry, the browser is free to interpolate between table entries or round off to the closest one. The browser may have to extrapolate table values if the numerical value goes beyond the keywords. Length and percentage values should not take the font size table into account when calculating the font size of the element.

On all other properties, 'em' and 'ex' length values refer to the font size of the current element. On the 'font-size' property, these length units refer to the font size of the parent element.

Note that an application may reinterpret an explicit size, depending on the context. E.g., inside a VR scene a font may get a different size because of perspective distortion.

If the suggested scaling factor of 1.5 is used, the last three declarations are identical.

font-family
Value: [[<family-name> | <generic-family>],]* [<family-name> | <generic-family>]
Initial: UA specific
Applies to: all elements
Inherited: yes
Percentage values: N/A

The value is a prioritized list of font family names and/or generic family names. Values are separated by a comma to indicate that they are alternatives:

<font-family>
The name of a font family of choice. In the last example, "gill" and "helvetica" are font families.

<generic-family>
In the example above, the last value is a generic family name. The following generic families are defined:

It is useful to offer a generic font family as a last alternative, in case the specified font is not available on the viewers system.

font-weight
Value: normal | bold | bolder | lighter | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900
Initial: normal
Applies to: all elements
Inherited: yes
Percentage values: N/A

The 'font-weight' property selects the weight of the font. The values '100' to '900' form an ordered sequence, where each number indicates a weight that is at least as dark as its predecessor. The keyword 'normal' is synonymous with '400', and 'bold' is synonymous with '700'. Keywords other than 'normal' and 'bold' have been shown to be often confused with font names and a numerical scale was therefore chosen for the 9-value list.

The 'bolder' and 'lighter' values select font weights that are relative to the weight inherited from the parent:

font-style
Value: normal | italic | oblique
Initial: normal
Applies to: all elements
Inherited: yes
Percentage values: N/A

The 'font-style' property selects between normal (sometimes referred to as "roman" or "upright"), italic and oblique faces within a font family.

A value of 'normal' selects a font that is classified as 'normal' in the browsers (typically, the systems) font database, while 'oblique' selects a font that is labeled 'oblique'. A value of 'italic' selects a font that is labeled 'italic', or, if that is not available, one labeled 'oblique'.

The font that is labeled 'oblique' in the UA's font database may actually have been generated by electronically slanting a normal font.

Fonts with Oblique, Slanted or Incline in their names will typically be labeled 'oblique' in the UA's font database. Fonts with Italic, Cursive or Kursiv in their names will typically be labeled 'italic'.

font-variant
Value: normal | small-caps
Initial: normal
Applies to: all elements
Inherited: yes
Percentage values: N/A

Another type of variation within a font family is the small-caps. In a small-caps font the lower case letters look similar to the uppercase ones, but in a smaller size and with slightly different proportions. The 'font-variant' property selects that font.

A value of 'normal' selects a font that is not a small-caps font, 'small-caps' selects a small-caps font. It is acceptable (but not required) in CSS1 if the small-caps font is a created by taking a normal font and replacing the lower case letters by scaled uppercase characters. As a last resort, uppercase letters will be used as replacement for a small-caps font.

The following example results in an 'H3' element in small-caps, with emphasized words in oblique small-caps:

There may be other variants in the font family as well, such as fonts with old-style numerals, small-caps numerals, condensed or expanded letters, etc. CSS1 has no properties that select those.

font
Value: [<font-style> || <font-variant> || <font-weight> ]? <font-size> [ / <line-height> ]? <font-family>
Initial: not defined for shorthand properties
Applies to: all elements
Inherited: yes
Percentage values: allowed on <font-size> and <line-height> only

The 'font' property is a shorthand property for setting 'font-style' 'font-variant' 'font-weight' 'font-size', 'line-height' and 'font-family' at the same place in the style sheet. The syntax of this property is based on a traditional typographical shorthand notation to set multiple properties related to fonts.

For a definition of allowed and initial values, see the previously defined properties. Properties for which no values are given are set to their initial value.

In the second rule, the font size percentage value ('80%') refers to the font size of the parent element. In the third rule, the line height percentage refers to the font size of the element itself.

In the first three rules above, the 'font-style', 'font-variant' and 'font-weight' are not explicitly mentioned, which means they are all three set to their initial value ('normal'). The fourth rule sets the 'font-weight' to 'bold', the 'font-style' to 'italic' and implicitly sets 'font-variant' to 'normal'.

The fifth rule sets the 'font-variant' ('small-caps'), the 'font-size' (120% of the parent's font), the 'line-height' (120% times the font size) and the 'font-family' ('fantasy'). It follows that the keyword 'normal' applies to the two remaining properties: 'font-style' and 'font-weight'.

@font-face
Value: {font-family : <font-family>; url(<url>;)
Initial: not defined
Applies to: all elements
Inherited: yes
Percentage values: n/a

The @font-face property specifies a font to embed into your HTML document. This feature allows you to use specific fonts that might not be available on your local system. The URL should point to an embedded OpenType file (.eot or .ote format). The file contains compressed, subsetted font data that is converted to a TrueType font and installed by T2embed.dll.