Hi @rickardp,
Assuming the query outputs the correct data, I think the problem lies in the way you are trying to access {{rows.[0].color}} in the fill argument.
Fill is expecting a hex code, so it won't understand the handlebars template you are trying to give it; it's probably just thinking you provided a malformed color string, and falls back to black.
In order to get the correct hex code, you'll want to use the getCell function as a subexpression to pull the cell from the correct place:
fill={getCell column="color" r=0}
This is going to take the color value from the first row of results and pass it as the fill, which (I think) is what you are trying to do.
Hope this helps!