Theme Horse

@myzhang Select the narrow layout for the site layout options. Then in the dashboard, go to Appearance->Theme Options->Design Options Tab->Custom CSS. Paste the following css and click on ‘Save all Changes’.

#main {
background-color: transparent;
}
.narrow-layout {
max-width: none;
}

Now, set the background from Appearance->Background. Now, after all this it will be all similar to the free version background setting. Hope this helps.