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INDUSTRY Target

Fix CSS Grid Broken Columns in Mozilla Thunderbird — HubSpot 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 CSS Grid Broken Columns inside Mozilla Thunderbird templates when using HubSpot.

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.

HubSpot Behaviors

HubSpot's COS template manager automatically wraps content blocks in dynamic div structures to support their drag-and-drop system. These extra wrappers force styling inheritances that override inline td paddings, leading to spacing collapses in Outlook. Setting explicit table element attributes is crucial. 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

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 HubSpot campaign manager, make sure you configure your links to run via {{ unsubscribe_link }}.

<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

Interactive HubSpot Custom Sandbox

Target Environment: Mozilla Thunderbird

How to Deploy inside HubSpot

1

Copy the fixed VML or table wrapper code block from the remediation box above.

2

In HubSpot's Design Manager, edit the modules section. Create a 'Rich Text' or 'HTML' module block. Double-click the block, choose 'Tools' or 'Advanced', click 'Source Code', and drop the code snippet inside.

Targeted Fixes by Use Case & Industry