Dark mode isn't just a passing trend.Every year, more and more users read their email in dark interfaces:

  • in Gmail,
  • Apple Mail,
  • Outlook,
  • mobile clients.

If your design isn't adapted for dark mode, the email can end up looking broken or hard to read.In this article, we'll cover how to prepare emails for dark mode, even if you're not a coder.

Why does dark mode matter?

✔ Over 50% of users have dark mode turned on on their smartphone.✔ An unprepared design can:— "break" (the text blends into the background),— lose your brand colors,— look unprofessional.

How do email clients handle dark mode?

Email clients adapt emails in different ways:

  • Inverting the background and text (for example, a light background becomes dark).
  • Partial color replacement (system elements turn dark, but the image stays as is).
  • Ignoring CSS styles.

Important: you can't just trust the code — you need to test it.

Step 1. Use transparent images

✅ PNGs with a transparent background look better.❌ A JPG with a white background can stick out awkwardly in dark mode.

Step 2. Set the background explicitly

In the Letteros editor:

  • set a block's background explicitly (background-color),
  • avoid a "default white" background — dark mode might repaint it black.

Step 3. Check contrast

  • Text needs to be readable against a dark background.
  • Avoid gray text on a gray background.
  • The minimum contrast is 4.5:1 (per the WCAG standard).

Step 4. Test across different clients

  • Gmail (mobile and desktop),
  • Outlook,
  • Apple Mail.

Letteros has a preview feature, and you can also send a test email to your own inbox.

Step 5. Use safe colors

✅ Black (#000), white (#fff), and saturated brand colors.❌ Complex light shades often get distorted.

Step 6. Add fallback solutions

For example:

  • text alternatives for images,
  • backup styles (for example, !important for key colors).

Conclusion

Supporting dark mode isn't just a "nice to have" — it's the standard for good email design in 2025.With Letteros, you can prepare dark-mode-ready emails even without a coder, just by using ready-made modules.