Email signatures in dark mode
Many people read email in dark mode, and some mail apps recolor your message, signature included, to match. You can't control exactly how each app does it, but you can make a signature that stays readable whatever happens. Here's what the major apps do, as far as it is documented, and how to prepare for it.
What mail apps do to your signature
There are broadly three behaviors: the app leaves the message alone, it darkens light backgrounds while keeping dark colors (“partial inversion”), or it inverts light and dark colors throughout (“full inversion”). Google doesn't document how the Gmail apps recolor messages, and Microsoft and Apple describe only the settings, not the color rules. The table below combines the vendors' help pages with the client-by-client chart published by the email testing company Litmus (as of February 2025). Behavior can change with app updates, so treat it as a guide and test with your own accounts.
| Mail app | What happens to the email | Notes |
|---|---|---|
| Gmail on the web (desktop) | No change to the message | The Gmail interface can be dark, but the email itself keeps its colors. |
| Gmail app for Android | Partial inversion | Light backgrounds become dark; colors that are already dark are mostly kept. |
| Gmail app for iPhone and iPad | Full inversion | Light and dark colors are both inverted. |
| Outlook.com, Outlook for iOS and Android | Partial inversion | Microsoft documents a “Turn on the lights” button (web) to show the original formatting. |
| Classic Outlook for Windows (Microsoft 365) | Full inversion | Microsoft documents a sun/moon button to switch the message background, and a setting to never change it. |
| Apple Mail (Mac, iPhone) | Usually no change | Apple documents a setting to show messages with a dark background; how it treats an email depends on the email's own code. |
Readers can also switch it off. In Outlook, Microsoft documents a sun/moon button (classic Outlook) and a “Turn on the lights” button (new Outlook and Outlook on the web) that show a message on a light background. In Apple Mail on the Mac, “Use dark backgrounds for messages” in Mail's Viewing settings controls it, and it's only available when the Mac's appearance is set to Dark.
See the problem: a rough simulation
The previews below imitate a full-inversion app with a CSS filter: every color in the HTML is inverted, while images are left as they are. It's an illustration, not a screenshot of any real app, but it shows what goes wrong and what survives.
 | Elena Petrova Head of IT Polar Systems | |
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| Made with Fairsig | ||
| Elena Petrova Head of IT Polar Systems | |
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| Made with Fairsig | ||
| Elena Petrova Head of IT Polar Systems | |
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| Made with Fairsig | ||
Partial-inversion apps (which only darken light backgrounds) are kinder to the second version, but you can't choose which kind of app your readers use. That's why a background inside the image file itself is the most predictable fix.
Transparent logos: three fixes
- Flatten the logo onto a background. Export the PNG or JPG with a white (or brand-colored) background and a little padding around the mark. In dark mode it becomes a neat light tile; in light mode it looks the same as before. This is the most predictable option.
- Add a thin light outline or glow. If you want to keep transparency, a subtle white stroke or glow around dark lettering keeps it readable on a dark background. Litmus recommends this approach for transparent PNGs with dark text.
- Use a mid-tone logo color. Very dark navy or black marks vanish on dark backgrounds, and pure white marks vanish on light ones. A mid-tone version of your logo reads on both.
Leave enough padding around the mark (a few pixels at display size) so the light tile doesn't look cramped. Upload the logo at twice its display width for sharpness: see the size guide.
Text and colors
- Avoid pure black text and pure white backgrounds in the signature. Mid-gray text survives darkening and inversion better than #000000.
- Pick an accent color that has contrast on both light and dark backgrounds. Medium blues, teals and purples usually do; very pale or very dark accents don't.
- Don't put text in images. A slogan baked into a banner won't be recolored with the rest and may clash with a dark background. Real text adapts.
- Prefer gray social icons if you use icons: they read on both backgrounds. See social media icons.
Dark-mode friendly examples
All three use Fairsig's “Dark-mode friendly” option. Open one in the generator and replace the details (and the logo address) with yours.
Logo flattened onto a light tile
| Elena Petrova Head of IT Polar Systems | |
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| Made with Fairsig | ||
The logo file has its own white background and padding, so there's no transparency for a dark theme to expose. In dark mode it shows as a neat light tile.
Dark-mode friendly, with photo
 | Owen Price Customer Success Lead Polar Systems  |
| Made with Fairsig | |
Mid-tone text, a photo with its own background (no transparency to lose) and gray icons that read on both light and dark backgrounds.
Dark-mode friendly
| Elena Petrova Head of IT Polar Systems | |
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| Made with Fairsig | ||
Mid-tone text survives the color inversion that dark-mode mail apps apply, and the dark logo gets a light pad so it doesn't vanish on a black background.
Why signatures can't switch images like newsletters do
Marketing emails sometimes swap a light logo for a dark one with a prefers-color-scheme media query in a <style> block. A signature is pasted into your mail app's signature editor as inline HTML; Fairsig signatures use inline styles only, with no <style> block, because they need to survive that editor. So the practical approach is a single design that's readable in every mode.
How to test
- Paste your signature into your mail app (guides: Gmail, Outlook, Apple Mail).
- Send a test email to an account you can open on a phone and on a computer.
- Turn dark mode on in the phone's system settings and in the mail app, and look at the logo, the accent color and the small print.
- If something disappears, apply one of the fixes above and send again.
Questions
Can I make my signature look the same in light and dark mode?
Not completely. Each mail app decides how to recolor messages, and a signature can't carry the style rules that newsletters use to switch colors. What you can do is make it readable in every mode: mid-tone text, a logo that has its own background or outline, and no information that exists only in an image.
Why does my logo disappear in dark mode?
It's probably a transparent PNG with dark lettering. When the mail app turns the background dark, the dark letters sit on a dark background. Give the logo a light background inside the image file, or add a thin light outline or glow around the dark parts.
Should I use a white or a transparent background for my logo?
A background baked into the image is the most predictable: the logo looks the same everywhere, as a light tile in dark mode. Transparent PNGs look more elegant in light mode but need an outline or glow to survive dark mode.
What does Fairsig's “Dark-mode friendly” option do?
It switches the text to mid-gray tones that stay readable whether the app keeps, darkens or inverts the colors, and places logos on a small white pad. Apps that fully invert colors may darken that pad too, so a logo file with its own background is still the safest choice.
Sources
- Microsoft Support, Dark Mode in Outlook.
- Apple Support, Change Viewing settings in Mail on Mac.
- Litmus, The Ultimate Guide to Dark Mode for Email Marketers (support chart as of February 2025).
All checked in October 2026. We found no Google help page that describes how Gmail recolors received messages.
Ready? The free Fairsig generator builds a signature that works in Gmail, Outlook and Apple Mail, in your browser, with no sign-up. Create a dark-mode friendly signature →