I created a new Articulate community skin that improves the functionality in my first effort to cover up the Articulate player borders.
With this new community skin you can cover the standard Articulate player borders with a frame that is the same color as your HTML page and PowerPoint slide background allowing seamless integration of your content into your web page. The skin is setup for slide-only view and does not include any type of navigation, tabs, or other controls. You must provide all navigation control through your PowerPoint slides. The slides display at 118% of their usual size in Articulate.
To customize this skin for your project, you need to edit the colors of the slide background and HTML background in the Articulate player template and you must edit the slide background in the PowerPoint slide master. If the same color value is set for these three variables, your Articulate publication will blend seamlessly into your web page.
The player border is covered with rectangles that take on the color you set for the slide background in the Articulate player template. So you could try out some other effects by choosing different colors for the HTML background and the PowerPoint slide background. Here is a demonstration presentation in which the Articulate slide background and HTML background and the PowerPoint background are all set to the same color.
You can purchase this skin along with the complete documentation from the Shop page on this website.