Change newsletter view background colour

How do I change the newsletter view background colour? The webpage I'm trying to change is here: http://www.despectus.co.uk/index.php/newsletter?layout=newsletterview&nid=1

I want to change the colour to beige. I have tried the following in my custom.css file without luck.

.nsprotable #nspro_preview_message {
background: beige;
}

Regards
Ben

Hello Ben and thank you for posting.
I am sorry for the late response, but due to a recent relocation I am out of an internet connection, temporarily.

You should be able to change it the way you mention. Have you tried to add !important ?
Maybe that would help.

Thanks again.

Hi,
I added !important now, but still no luck.

This is the block of code added to the custom.css file.

#nsprotable .nspro_preview_message {
color: #000;
margin: 0px;
padding: 0px;
font-size: 100%;
font-style: normal;
font-weight: normal;
background: beige !important;
}

Hi again Ben.
Sorry for the late response. All is back to normal now, after the relocation.
I just visited your page and I can see the background being beige. I'm using Chrome on Windows 10.
Do you still have this problem? If yes, which browser are you using?