Do HTML/CSS/JavaScript define constants representing system theme colours? I mean those colours a user can define in the operating system (or a browser) control panel. Like standard window contents background and text colours etc.
The idea is to make a web site to respect the user preferences by default, showing light text on dark background in case the user uses such a theme in his system (while following the Occam's razor principle by avoiding introducing extra configuration).
Yes you can,
Open firebug and change some css declaration like color : ActiveBorder or see webdesign.about.com/od/colorcharts/l/blsystemcolors.htm or search the net for 'css system colors'
For a better reference suggested by unor about system colors
CSS 2.1 specifies "System Colors":
In addition to being able to assign pre-defined color values to text, backgrounds, etc., CSS2 introduced a set of named color values that allows authors to specify colors in a manner that integrates them into the operating system's graphic environment.
Example:
to set the foreground and background colors of a paragraph to the same foreground and background colors of the user's window, write the following:
p { color: WindowText; background-color: Window }
In CSS Color Module Level 3, these system colors are deprecated, "in favor of the CSS3 UI ‘appearance’ property". But it seems that this has been dropped, too (you can still find it in older drafts).
