How to modify the font of Line Numbers.

Word 2007 sets the font of the line numbers to be the same as the “Default Paragraph Font,” but you can modify the font.
To modify the line number font you need to get to the style “Line Number,” and then modify the style.

Here’s how to do this:

In Home go to Styles.
Click on the bottom right hand double arrow of Styles to open a list of Styles window (this doesn’t list all the styles used in the document!)
In the list of Styles window click Options… (bottom right hand corner) to open a “Style Pane Options” dialog box.
In the dialog box, in “Select Styles to Show” choose All Styles (NOT “In current Doc” or “In use” – neither of these get to Line Number).
Select “Line Number,” and then Modify (you have to click the symbol on the right hand side of “Line Number” to get to Modify).
This gets you to the Modify Style dialog box, which lets you change the font of the Line Numbers.

Now to my question:
I can set upper and lower margins using Top and Bottom Margins in the Page Setup dialog box.
In the Header and Footer tools (double click header/footer of document to open this), I can set the distance of the Header from Top, and the distance of the Footer from bottom.

If I set the distance of the Header from top too big, it seems to push down the upper margin text. (Same problem for footer.)

So what is the relation between the “Top Margin” setting and the “Distance of the header from top” setting? (same question for the footer.)