font-sizeFor scalable fonts, the font-size is a scale factor applied to the EM unit of the font. (Note that certain glyphs may bleed outside their EM box.) For non-scalable fonts, the font-size is converted into absolute units and matched against the declared font-size of the font, using the same absolute coordinate space for both of the matched values.

]]> | | | ;]]>]]>An <absolute-size> keyword refers to an entry in a table of font sizes computed and kept by the user agent.

]]>]]>A <relative-size> keyword is interpreted relative to the table of font sizes and the font size of the parent element.

]]>]]>A length value specifies an absolute font size (that is independent of the user agent's font table). Negative lengths are illegal.

]]>]]>A percentage value specifies an absolute font size relative to the parent element's font size. Use of percentage values, or values in ems, leads to more robust and cascadable style sheets.

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