Changing colours in Studio theme activity panel

Hi - I'm trying to change the background colour of the activity panel (the slide out when you click "Our Community") in Studio theme.

Here's what I've done:

1. Enabled child-studio theme
2. Added the following to style.css in studio-child

#panel {
padding-top: 10px;
border-top: 1px solid #444444;
width: 100%;
padding-bottom: 10px;
color: #999999;
background: #442812; <-- this is the colour change
overflow: hidden;
position: relative;
z-index: 3;
display: none;

... but not getting any changes :slight_frown:

What am I doing wrong?

You can view site here:

I'm VERY new to BuddyPress, reasonably proficient with WordPress tho.