There is nothing that you need to do here but good information to know. A table with the class .body will automatically wrap the email content and applies styles to give more consistent layout to the page. You can put classes on the <body> that will be moved onto the body table.
Input
<body class="bg-light">
...
</body>
Output
<body>
<table class="body bg-light">
...
</table>
</body>