Fix background color on PDF export

[SethFalco]

The website has a background color on it which is a very light gray.
The PDF version has this color on the background, but then goes #FFFFFF at the bottom where the resume finishes.

Bring consistency here, either by finding a way to fill the page with the color used on the website, disabling the background color on the PDF export, or removing the background color entirely if required.

In theory this should be possible by using the print media query and unsetting those styles when printing, but I need to explore this.

[SethFalco]

The main issue has been resolved for now in:

• fix: white background for lightmode #38

However, I will keep this ticket open as I'd like to investigate getting print media queries to work properly, so that we have a different background color between HTML and PDF exports.