it can be any color — black, blue, magenta — except for brown.
Making Emails Not-So-Scary Looking
Really Good Emails
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It couldn’t actually be any color. Brown is not the only exception to create the email white space. Do you think that red is the good color to use for the email background? Red or orange will probably not give the breathing room between elements but irritate and distract attention from the content. Plus, in this case email may fall into the spam folder easily as it would be ‘read as promotional’ by email clients.

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