changing background color

Hello,

I’m quite inexperienced with wp-I’m using the twenty-thirteen theme & added your blank slate plugin…which works great & did exactly what I wanted which was have a page without all of the menus on the top. I’ve tried a number of other plugins that haven’t helped me to change the background color, I’m assuming because you load the file temporarily. I’ve attempted to add this code:

.postid-2811 { background-color: #ccc; }

to the: blank-slate/blank-slate-template.php file & the background color doesn’t change

Please help if you can, I’d really appreciate it, thanks

https://wordpress.org/plugins/blank-slate/