Best practices for dark mode optimization
Joey Lee
October 13, 2025
Dark mode is more than a UI trend. It’s an inbox reality. As more users prefer darker interfaces for visual comfort, your emails need to be just as effective in the dark as they are in the light.
In this guide, we’ll explore why dark mode matters in email marketing, the challenges it brings, and the best practices your team should follow to ensure every email looks polished, on-brand, and accessible regardless of how it’s viewed.
Why dark mode matters in email
It’s everywhere: Most modern email clients support dark mode, including Apple Mail, Outlook, Gmail, and mobile apps.
It’s preferred: Up to 82.7% of mobile users now use dark mode in some form, with many defaulting to it full time.
It affects your design: Not optimizing for dark mode can lead to broken logos, unreadable text, or misaligned brand visuals.
🔍 Bottom line: If you’re not designing for dark mode, you’re not designing for your full audience.
What happens when emails render in dark mode
Dark mode rendering isn’t just a simple color inversion. Different email clients handle it in different ways:
Client | Dark mode behavior |
Apple Mail | Preserves your HTML and CSS but switches UI to dark |
Gmail (mobile) | May force color inversion on backgrounds and text |
Outlook | Often overrides styles with high-contrast themes |
Yahoo Mail | Partial inversion depending on user settings |
This inconsistency means your email might look perfect in one inbox and completely off-brand in another.
7 best practices for dark mode optimization
1. Use transparent PNGs for logos and icons
Solid white logos can disappear on dark backgrounds. Instead:
Use transparent PNGs
Add a subtle outline or shadow to maintain visibility
Avoid hardcoded white fills on SVGs
✅ Bonus: Consider adding a dark mode version of your logo if your brand allows.
2. Avoid pure black or pure white
Use soft neutrals to avoid harsh contrast:
Instead of #000000, try #121212
Instead of #FFFFFF, opt for #F1F1F1
These choices reduce eye strain and feel more natural in both light and dark environments.
3. Set background colors explicitly
Email clients that invert colors will only do so if backgrounds aren’t clearly defined.
Always define both background and text colors in your CSS
Example: <body style="background-color: #ffffff; color: #000000;">
Don’t rely on defaults, be specific and deliberate
4. Test for inversion behavior
Since every client handles dark mode differently, testing is critical. Some platforms force color inversion, while others respect your code.
At Scalero, we use Email on Acid to preview emails across dark mode environments before launch. It helps catch:
Unintended background inversions
Invisible text or logos
Layout shifts or CTA visibility issues
🧪 Tip: Always test in both desktop and mobile environments. Some clients behave differently even on the same device.
5. Use inline styles for maximum control
Dark mode overrides often ignore external stylesheets. That’s why we recommend:
Using inline styles like <td style="background-color: #ffffff; color: #000000;">
Setting fallback font colors to avoid unexpected overrides
6. Balance imagery with mode-neutral design
Background images can clash with inverted text or buttons.
Use image slices only when necessary
Favor solid-color HTML blocks with live text for readability
Always test your CTA buttons—what looks great in light mode may be unreadable in dark
7. Prioritize accessibility
Ensure your email is readable in every environment:
Maintain at least a 4.5:1 contrast ratio between text and background
Avoid relying on image-only emails; text may invert, but images won’t
Don’t place important copy directly over images unless you provide a strong HTML fallback
Pro tips for workflow integration
Use Email on Acid during QA to preview dark mode rendering across clients before launch
Add dark mode checks to your email QA checklist
Document your approach in your email design system for consistency across teams
Final thoughts
Dark mode isn’t a trend, it’s the new standard. By optimizing your emails for both light and dark viewing experiences, you reduce friction and increase readability, deliverability, and brand consistency.
Designing for dark mode takes effort, but the payoff is real. Your audience and your metrics will thank you.
Need help building dark mode-ready templates or testing your emails in Email on Acid? Reach out to our team. We’d be happy to help.
