Emailens
Web App

Dark Mode Simulation & Contrast

Preview client-specific dark mode transformations across WebKit, Blink, and Gecko engines with contrast warnings.

Different email clients handle dark mode with completely divergent rendering models. Emailens simulates the exact transformation logic used by each client so you can prevent illegible text or unreadable logos before sending.

Client Transformation Models

ClientTransformation ModelBehavior & Strategy
Apple Mail (iOS / macOS)Standards-Compliant (No Inversion)Honors @media (prefers-color-scheme: dark) and [data-ogsc] selectors. Leaves content untouched unless you supply custom dark styles.
Gmail WebNo InversionDarkens application chrome, leaving email body unchanged.
Gmail AndroidPartial InversionDetects light backgrounds and inverts them to dark; darkens text. Leaves elements with already-dark backgrounds alone.
Gmail iOSFull InversionForces full color inversion across the entire DOM tree, including elements that were already dark.
Outlook Web (OWA)Attribute InversionConverts inline styles to custom [data-ogsc] and [data-ogsb] attributes.
Outlook Windows (Classic)MSO InversionApplies Word rendering engine background swaps, occasionally leaving white borders around tables.
Samsung MailPartial InversionInverts light containers; respects prefers-color-scheme in modern versions.
ThunderbirdMedia Query FirstFull support for @media (prefers-color-scheme: dark) with fallback color shifting.

Automated Contrast Validation

Under the Dark Contrast audit tab, Emailens measures WCAG 2.1 AA/AAA compliance against inverted backgrounds. Common issues caught:

  • Dark logos on transparent PNGs: Disappear on inverted black backgrounds (fix: add subtle white outer glow or stroke).
  • Hardcoded white table cells: Clashing against inverted dark text.
  • Low-contrast muted text: #888888 fading below 4.5:1 ratio when client alters container luminosity.

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