Specifies the background for HTML documents. The background is valid for both new HTML documents and for those that you load, as long as these have not defined their own background.
བརྡ་བཀོད་འདི་འཛུལ་སྤྱོད་འབད་ནི་ལུ...
Open an HTML document, choose LibreOffice - PreferencesTools - Options - LibreOffice Writer/Web - Background.
Click a color. Click the None button to remove a background color.