custom background color

[warmiak38]

 I set use a custom background color for websites, does anyone know how to get rid of what I marked with an arrow from the chrome-search: //local-ntp/local-ntp.html page, on other sites it's ok only on this particular one I get something like this .

[Admini]

This can only be changed by custom.css

[warmiak38]

This can only be changed by custom.css

You could do it for me because I have no idea about it.