One of the lesser-known features of CSS2.1 is the ability to define fonts and colors that are in use by the underlying Operating System theme. This can be useful in situations when you require tighter OS integration, e.g. HTML help files, Adobe AIR or perhaps offline web applications.

Before we begin, there are a few caveats:

• Do not rely on these properties working in all OS/browser combinations. If your application must work in Opera on BeOS, then I’d recommend you test it first!
• The properties have been deprecated in CSS3 in favor of the appearance value type (although browser support is extremely limited at this time).
• There is nothing to prevent the user defining unusual, clashing, or ugly color schemes in their OS. Pages will reflect their choices — not your designer’s.

System Fonts

System fonts are assigned using the ‘font’ property. Note that the family, size, and style are all assigned as appropriate, e.g.

body
{
	font: caption;
}

The following font values are available. The ‘Example’ column shows the current font set by your OS.

System Colors

System colors can be assigned to to any property that expects a color value, e.g.

body
{
	color: WindowText;
	background-color: Window;
	border: 2px solid ActiveBorder;
}

The following color values are available. They are shown in CamelCase for legibility, but any casing is valid. The ‘Example’ column shows the color set by your OS.

Would these properties be useful in your next project?

Written By:

Craig Buckler

Craig is a Director of OptimalWorks, a UK consultancy dedicated to building award-winning websites implementing standards, accessibility, SEO, and best-practice techniques.

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