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USE CASE Target

Fix CSS Flexbox Collapse in Apple Mail (Desktop) — SendGrid 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 Flexbox Collapse inside Apple Mail (Desktop) templates when using SendGrid.

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.

SendGrid Behaviors

SendGrid's template parser automatically injects custom style tags that can override inline styles. Always use inline style definitions and define clear target widths. 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

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 SendGrid 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="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

Interactive SendGrid Custom Sandbox

Target Environment: Apple Mail (Desktop)

How to Deploy inside SendGrid

1

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

2

Open SendGrid Design Editor, toggle the view mode to Code Editor, or insert a custom 'Code' module block inside your drag-and-drop layout. Drop the corrected code inside the box.

Targeted Fixes by Use Case & Industry