Fix CSS Grid Broken Columns in Mozilla Thunderbird — Brevo (Sendinblue) Guide for Editorial & Content Newsletters
Editorial newsletters rely on content layout readability and structural text spacing. If fonts default to Times New Roman or layout borders break, subscriber engagement metrics suffer. Below is the targeted integration guide to fix CSS Grid Broken Columns inside Mozilla Thunderbird templates when using Brevo (Sendinblue).
Technical Breakdown
Mozilla Thunderbird uses the Gecko which lacks support for standard rendering rules. This causes CSS Grid Broken Columns 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. Keep your editorial body clean. Strip redundant CSS class definitions using Vaporize to ensure the newsletter stays under Gmail's 102KB clipping ceiling.
Remediation Code Block
Always compile grid layouts using standard percentage-width or pixel-width nested tables aligned with the align='left' attribute. This acts as a responsive grid block that floats and adapts naturally to any viewport size. 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 width="48%" align="left" valign="top" style="padding-bottom:10px;">Col 1</td>
<td width="4%"></td>
<td width="48%" align="left" valign="top" style="padding-bottom:10px;">Col 2</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.