If for some reason the text editor box refuses to change the color of your background, there are a few things that can be done to change the color both in the HTML editor.
Source Code Editor:
There are multiple places you can change the background image in the editor, let’s start with the full width of the email.
As stated in the “Snippet Structure” blog post, the snippet contents is wrapped in a 600px table. The <table></table> itself sets the 600px width but the outer <td></td> is the full width of the email. Therefore to change the color of the full width background you need to edit the hex ref inside bgcolor=”” on the <td></td>. You also need to search the <td></td> for background-color:# which will be inside style=””. They both need changing to your preferred hex code.
For example: if you want to change a red background color (hex code #ff0000) to grey (hex code #444444) you need find the first <td></td> of the snippet and change bgcolor=”#ff0000″ to bgcolor=”#444444″ and change background-color:#ff0000 to background-color:#444444.
To change the background color of the 600px width table you need to do the exact same as above but to the first table of the snippet (the one that sets the 600px width):
When changing the padding of the snippet, the background of the td will be extended with the padding but the background of the 600px width table will not.