Cannot change Footer Background and text color

Hi there

We bought your theme to create a new business homepage.
So far only minor problems came up which i could fix on my own.

Now I am trying to change the background and the text color of the footer.
I already found replies to the same questions here, but your provided CSS code does not work.
It is just ignored.
I tried it in Theme Options -> Custom CSS
and in Simple Custom CSS plugin (the one I am using to change the active page color in the header).

The code i tried is this one:

#footer {
background: #461000;
}
.footer_btm {
background: #003131;
}

and

#footer {
color: #fff;
}

Both codeline are not working…

URL is:

http://web50.server57.webgo24.de/bau-cooperation.com