• For email client compatibility, we suggest that you use inline style attributes such as <div style="color: red;"></div> instead of CSS classes. 
    <style>
    @media only screen and (max-width:600px) {
        .a-unique-class { ... }
    }
    </style>

    <div class="a-unique-class">
    ...
    </div>
  • Include target=_blank to all links
  • Use the full path URL for all links to ensure they can be opened
  • In most cases, you shouldn’t apply a background color to your plugin (unless the user is able to customize it). This is because the user might be using a custom background color on their email. By not applying a background color, your element’s background will automatically be the same as their email.