Hi

Do you mean you want the website pages to fill the whole width of the screen?

If so this not desireable - your content will not flow as you expect on wider screens and a fixed width is easier to read and experience on widescreen monitors.

The current recommended width is between 1080 and 1366 px

See the following sections in the installed PDF manual:

• Selecting a page size
   
• Automatic page resizing

HTH

John