There are two ways to tackle the problem.
##Decoration from margin to margin
Insert a 1-row × 2-coumn table in header and footer and just select the desired cell background colour.
##Decoration from edge to edge (assuming your printer can do it)
Create a graphics image, e.g. in Draw, with the target dimensions, one for the header, one for the footer.
In the header, paste the image and review its properties (right-click on it and Properties):
- anchor To paragraph
- wrap does not matter because you don’t put any text in the header
- in
Type tab, Position section, center it horizontally to Entire page and vertically From top by xx cm to Entire page
Do the same in the footer.
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