Hi @Cedric,
It is indeed explained here how to add a background color to a table.
This code defines your table with “detail kosten” in it :
|-------#+
|**{% t "Detail van de kosten" %}**
So if you change that to this for example :
|-------#+5f5f5f
|**{% t "Detail van de kosten" %}**
you should be able to get the result you want.
BUT the background color will only be displayed in export (not in input-mode). So if you export it to a PDF, you’ll see what the code does (perhaps that’s why you couldn’t get it ? )
Can you give it a go?
If it works, then I’ll be gladly to explain your second question. Make sure to post the whole code then again, thanks!