Fix Gmail Line-Height Shifts in Mozilla Thunderbird — Klaviyo 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 Gmail Line-Height Shifts inside Mozilla Thunderbird templates when using Klaviyo.
Technical Breakdown
Mozilla Thunderbird uses the Gecko which lacks support for standard rendering rules. This causes Gmail Line-Height Shifts elements to break or collapse when rendering templates.
Klaviyo Behaviors
Klaviyo's drag-and-drop template parser automatically wraps all user-defined block sections in proprietary 'kl-part' class selectors. When rendering templates inside Microsoft Word engines (Outlook 2007-2021), Klaviyo's nested flex fallback blocks can cause structural tables to collapse or shift columns. You must use explicit table widths to override Klaviyo's styling wraps. Enforce strict WCAG color contrast standards across your statement tables and summary grids to ensure legibility and regulatory compliance.
Remediation Code Block
Define line-height as a unitless ratio (e.g. line-height: 1.4) or in explicit percentages (e.g. line-height: 140%). Avoid mixing em and px units, and apply the styles directly to the containing td or span tags containing typography. In your Klaviyo campaign manager, make sure you configure your links to run via {% unsubscribe %}.
<p style="font-size: 16px; line-height: 22px; margin: 0; mso-line-height-rule: exactly;">Typography Paragraph</p>Live Code Sandbox Test
How to Deploy inside Klaviyo
Copy the fixed VML or table wrapper code block from the remediation box above.
Open your Klaviyo template editor. Drag an 'HTML' block directly into your layout timeline (do not use a standard text box). Clear the default skeleton content inside the Klaviyo markup editor and paste the RenderOps corrected inline code.