Fix CSS Grid Broken Columns in Mozilla Thunderbird — ActiveCampaign Guide for B2B Cold Outreach
B2B cold outreach templates demand maximum deliverability and a plain-text appearance. Heavy, broken CSS structures or HTML syntax issues trigger spam filters instantly. Below is the targeted integration guide to fix CSS Grid Broken Columns inside Mozilla Thunderbird templates when using ActiveCampaign.
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.
ActiveCampaign Behaviors
ActiveCampaign's editor parses HTML template imports and automatically cleans inline attributes, which can break VML tags. Always use absolute styles and avoid relying on classes. For cold sales outreach, minimize VML structures and prioritize light, standard text blocks to maximize inbox placement on corporate enterprise filters.
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 ActiveCampaign campaign manager, make sure you configure your links to run via %UNSUBSCRIBELINK%.
<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 ActiveCampaign
Copy the fixed VML or table wrapper code block from the remediation box above.
Insert an 'HTML block' from the layout builder panels. Avoid standard text boxes, as the ActiveCampaign parser might strip conditional MSO comment strings on saving.