Fix Custom Font Fallback Overrides in Yahoo Mail — HubSpot Guide for WCAG Accessibility Violations
Accessibility failures prevent screen readers from navigating templates, isolating disabled subscribers and increasing unsubscribe rates. Below is the targeted integration guide to fix Custom Font Fallback Overrides inside Yahoo Mail templates when using HubSpot.
Technical Breakdown
Yahoo Mail uses the WebKit / Blink Web Wrapper which lacks support for standard rendering rules. This causes Custom Font Fallback Overrides 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. Inject correct table roles (role='presentation') and keep color pairings above the WCAG AA contrast threshold of 4.5:1.
Remediation Code Block
To prevent Outlook's Times New Roman fallback override, wrap your custom font declarations inside an @media block that Outlook ignores, or use MSO conditional statements to override font-families specifically for Microsoft Word rendering engines. In your HubSpot campaign manager, make sure you configure your links to run via {{ unsubscribe_link }}.
<!--[if mso]>
<style type="text/css">
body, table, td { font-family: Arial, sans-serif !important; }
</style>
<![endif]-->
<style>
@import url('https://fonts.googleapis.com/css2?family=Montserrat&display=swap');
</style>Live Code Sandbox Test
How to Deploy inside HubSpot
Copy the fixed VML or table wrapper code block from the remediation box above.
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.