<mjml>
  <mj-head>
    <mj-attributes>
      <mj-class name="green-bg" background-color="green" />
    </mj-attributes>
  </mj-head>

  <mj-body>
    <mj-section mj-class="green-bg">
      <mj-column>
        <mj-text>some text</mj-text>
      </mj-column>
    </mj-section>
  </mj-body>
</mjml>
