Fix CSS Flexbox Collapse in Yahoo Mail — MJML Framework Guide for Financial Services & Banking
Financial emails carry high-compliance requirements. Layout collapses, overlapping text, or accessibility failures can lead to compliance audits and client confusion. Below is the targeted integration guide to fix CSS Flexbox Collapse inside Yahoo Mail templates when using MJML Framework.
Technical Breakdown
Yahoo Mail uses the WebKit / Blink Web Wrapper which lacks support for standard rendering rules. This causes CSS Flexbox Collapse elements to break or collapse when rendering templates.
MJML Framework Behaviors
The MJML transpilation compiler parses dynamic columns and wraps them in custom HTML conditional tags. If you paste direct tables or VML code blocks inside an MJML layout without proper escaping, the MJML compiler will try to clean the code, resulting in stripped Outlook namespaces and broken layouts. Enforce strict WCAG color contrast standards across your statement tables and summary grids to ensure legibility and regulatory compliance.
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 MJML Framework 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="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 MJML Framework
Copy the fixed VML or table wrapper code block from the remediation box above.
Wrap the entire RenderOps corrected table block inside an '<mj-raw>' tag block. This tells the MJML compiler to bypass parsing on this segment, exporting the exact conditional statements into the final HTML output.