View.PageColor (Word)

Returns and sets the page color in Reading mode. Possible return values are wdPageColorInverse - Inverse page color. Renders the document content in a manner that resembles high-contrast black, although not necessarily exactly so. Some figures are rendered in full color on a black background, wdPageColorNone - No page color, the default. The page background is rendered in white. Any assigned page background colors are ignored, wdPageColorSepia - Sepia page color, RGB (112, 66, 20) at 80% transparency. Makes no changes to the contents of the document.

ActiveWindow.View.PageColor = wdPageColorInverse