Fix CSS Flexbox Collapse in Apple Mail (Desktop) — Salesforce Marketing Cloud (SFMC) Guide for eCommerce Campaigns
In eCommerce email marketing, rendering issues directly tank conversion rates and cart recoveries. Product grids, checkout CTAs, and discount banners must display flawlessly to prevent purchase drop-offs. Below is the targeted integration guide to fix CSS Flexbox Collapse inside Apple Mail (Desktop) templates when using Salesforce Marketing Cloud (SFMC).
Technical Breakdown
Apple Mail (Desktop) uses the WebKit which lacks support for standard rendering rules. This causes CSS Flexbox Collapse elements to break or collapse when rendering templates.
Salesforce Marketing Cloud (SFMC) Behaviors
SFMC's Content Builder wraps block exports in div frames that can break conditional comments. Additionally, AMPScript calls for personalizations can trigger parsing errors if they are inside MSO conditional comments. Ensure your AMPScript tags are evaluated *outside* the VML blocks. Double-check your dynamic product feed blocks. When injecting product loops from your catalog, ensure width sizes are explicitly handled to keep columns from overlapping.
Remediation Code Block
To resolve this, modern layouts must be compiled down to Outlook-compliant nested HTML table models. Each flex container becomes a table row, and each flex child becomes a table data cell (td) with explicit pixel or percentage widths. In your Salesforce Marketing Cloud (SFMC) campaign manager, make sure you configure your links to run via %%unsubscribe_url%%.
<table role="presentation" border="0" cellpadding="0" cellspacing="0" width="100%">
<tr>
<td width="50%" valign="top" style="padding: 20px;">Column 1</td>
<td width="50%" valign="top" style="padding: 20px;">Column 2</td>
</tr>
</table>Live Code Sandbox Test
How to Deploy inside Salesforce Marketing Cloud (SFMC)
Copy the fixed VML or table wrapper code block from the remediation box above.
Create an 'HTML content' layout block in Content Builder. Paste the table structure. Enclose any custom merge tags inside standard AMPscript wrapper lines.