Hello mercedescarter23,
Hope you’re well! 🙂
The main and sidebar section are separate by default. It is just their parent element was the one use to set the background color. I suggest you use a child theme http://codex.ww.wp.xz.cn/Child_Themes or use css custom plugin like this: https://ww.wp.xz.cn/plugins/simple-custom-css/ if you will customize your theme.
Here is the code ( I left comment for better explanation ) you can put on your child theme’s style.css or use the plugin mentioned above:
/*
remove the bg color - this is the parent of main and sidebar element so if you put a color on this the two will be affected
you can also put a color on this element while main and sidebar have their own color. RESULT: http://prntscr.com/5pg7ng
*/
.container {
background-color: none;
}
/* this element can have its own bg color */
#content {
background-color: red
}
/* this element can have its own bg color */
#sidebar {
background-color: green
}
Hope it helps! 🙂
Take care,
Calvin