Change Background color

Dear developers, I need your help in SequenceServer settings.

I need to configure the background colour in order to fit SequenceServer with my website’s background colour, precisely, I need the colour can be changed between black and white, but I don’t know how to do this in your code.

Here is what I did to change the background color:
In the file views/layout.erb:
Change the body tag to:

The markdown didn’t see my code:
Here is what I meant to write:
<body style='background:#BFD4DB;'>