Question about paper color in PDF Viewer

Hello dear developers!
HTML Executable lets you integrate a stand-alone PDF viewer.

The documentation states:
When the PDF viewer engine loads a PDF document, it triggers the [OnPDFDisplay] event.
In list of available commands and description / parameter value for [PDFViewerCommand]:
Command ID – 54
Select the paper color. Param is a RGB value.

I write to the UserMain script
Trying options 1 or 2
I get the error

procedure OnPDFDisplay(PDFPath: String);
begin

• 1. Code:

     PDFViewerCommand(54, (255, 255, 255));*

• 1. Code:

     PDFViewerCommand(54, rgb (255, 255, 255));*

end;

Please tell me - how to do it right?
Thank you so much!

RGB is not known. You must pass an integer value that is computed with rgb (255, 255, 255): you get 16777215.
rgb = 65536 * r + 256 * g + b;