Edit your HomeDirectory/.Xdefaults file by adding these resources:
application_name*DtHelpDialog*DisplayArea.foreground: color application_name*DtHelpDialog*DisplayArea.background: color application_name*DtHelpDialog*TocArea.foreground: color application_name*DtHelpDialog*TocArea.background: color application_name*DtHelpQuickDialog*DisplayArea.foreground: color application_name*DtHelpQuickDialog*DisplayArea.background: color
Substitute the name of the application whose help windows you want to change for application_name.
You can ask your system administrator for a list of colors that you can use or refer to your system documentation.
Save and close the file.
When you restart your application, it will use the new color values for the topic tree and topic display area in its help windows.
For example, these resource entries change the foreground and background colors of the topic tree (TocArea) and topic display area (DisplayArea) for an application named DtCardCatalog.
DtCardCatalog*DtHelpDialog*TocArea.foreground: yellow DtCardCatalog*DtHelpDialog*TocArea.background: blue DtCardCatalog*DtHelpDialog*DisplayArea.foreground: yellow DtCardCatalog*DtHelpDialog*DisplayArea.background: blue DtCardCatalog*DtHelpQuickDialog*DisplayArea.foreground: yellow DtCardCatalog*DtHelpQuickDialog*DisplayArea.background: blue
Quick help windows do not have a topic tree, so the TocArea resource is omitted.