If your company uses one specific Office theme for one reason or another, you can enable higher fidelity transformations from Open XML WordprocessingML to Html. You can configure the HtmlConverter class to use the styling of one of the Office themes in its generation of Html. This screen-cast walks through the pretty simple process of using any given theme in the Html generation. No code is attached - this screen-cast relies on the download of the core classes in PowerTools for Open XML.