One thing that took a little investigation (and a very fast response from the developer), was how to customise the PDF output - i.e. how to change the default styling.
The answer is really simple, go to Preferences -> CSS -> Edi, and open the CSS file.
Then you just use the @print media type, so for example, the following snippet will make the output text black:
@media print { body { color: black; } }
Don't forget to reload your CSS afterwards for it to take effect !