Fix Padding & Margin Collapsing in Mozilla Thunderbird — Brevo (Sendinblue) Guide for Retail & Consumer Brand Campaigns
Retail campaigns rely on high-fidelity visual assets, coupon borders, and clear promotional layouts. Default image blocking or button collapses disrupt the visual journey. Below is the targeted integration guide to fix Padding & Margin Collapsing inside Mozilla Thunderbird templates when using Brevo (Sendinblue).
Technical Breakdown
Mozilla Thunderbird uses the Gecko which lacks support for standard rendering rules. This causes Padding & Margin Collapsing elements to break or collapse when rendering templates.
Brevo (Sendinblue) Behaviors
Brevo's rendering system injects inline spacing helpers to support their responsive editor, which can cause column overlaps in Outlook. Using explicit table alignments is required. Always define ALT descriptions for retail product shots, and base64-encode your brand logo so the email headers render cleanly even when images are blocked.
Remediation Code Block
To ensure spacing works reliably, apply all structural paddings directly to HTML td elements inside tables. Do not apply paddings or margins to raw divs, as Outlook will strip them. For vertical spacing, use explicit spacer tables or empty rows. In your Brevo (Sendinblue) campaign manager, make sure you configure your links to run via {{ unsubscribe }}.
<table role="presentation" border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td height="20" style="font-size: 1px; line-height: 1px;"> </td>
</tr>
<tr>
<td style="padding: 15px; background-color: #f1f1f1;">
Content with padding and margin
</td>
</tr>
<tr>
<td height="20" style="font-size: 1px; line-height: 1px;"> </td>
</tr>
</table>Live Code Sandbox Test
How to Deploy inside Brevo (Sendinblue)
Copy the fixed VML or table wrapper code block from the remediation box above.
Open Brevo's template canvas, select the element you wish to configure, click 'Edit HTML' or insert a standalone 'HTML' content block, and paste the code.