Three ways apps handle dark mode
Litmus, which tests email across clients for a living, sorts mail apps into three groups. Its February 2025 chart gives these examples:
| What the app does | Litmus's examples |
|---|---|
| No colour change: the email looks the same in light and dark mode | Apple Mail, Gmail on a desktop, AOL, Yahoo Mail |
| Partial invert: light backgrounds are made dark, and dark areas are generally left alone | Outlook.com |
| Full invert: light backgrounds are made dark, and dark backgrounds are changed too | The Gmail app on iPhone, Outlook 2021 and Office 365 on Windows, Windows Mail |
Apps change from one version to the next, and other testers place some of them differently, so read this as what can happen rather than a promise of what will.
What happens to a signature
In an app that changes nothing, a signature looks exactly as you made it, however dark the app around it. In a partial invert, a light card is turned dark and its dark text light, so a white card with black text can arrive as a dark card with white text. In a full invert, dark parts can change too, so a navy card or a coloured banner may not keep the colour you chose for it. What usually moves is the brand colour, which is why a signature should not depend on it.
Logos that disappear
The one thing dark mode breaks outright is a dark logo on a transparent background. On white it looks fine; on a dark background, the background shows through around a dark mark and the mark all but vanishes. Litmus suggests giving a transparent picture with dark text a translucent outline so it stays legible. The other cure is a logo with a solid background of its own, a light tile or a coloured square, which keeps the mark visible whatever is behind it.
Why a signature cannot switch itself
A web page can ask whether its reader prefers dark mode and change its colours to suit, through a style block. A signature cannot: it sits in the body of an email, and Can I email records that Gmail does not support a style block inside the body. So a signature has one set of colours, and it is the set every reader gets. Choose them to look right on a white page and a dark one.
Light and dark designs
Eleven of Animated Signature's twelve designs come in a light and a dark scheme, and the Brand panel sets each scheme's colours. The scheme you choose is the one everyone sees: it does not follow the reader's mode, for the reason above. A dark scheme suits a brand that is dark already.
How to test yours
- Send an email with your signature to an address of your own on another service.
- Switch your phone to dark mode and open it in the phone's mail app, then in another app if you have one.
- Do the same on a computer, in a browser's webmail and in a desktop app.
- Look for a logo that has vanished, text that has lost its contrast, and a banner that has changed colour.