The first Dark Mode theme is what I like to call a “Partial Color Inversion”. It only detects areas with light backgrounds and inverts them so that light backgrounds are dark, while dark text becomes light. It usually leaves areas that already have dark backgrounds alone, resulting in an entirely dark mode design. Luckily, most email clients that use this method also support dark mode targeting, so you can override the client's default dark theme. Outlook.com is an email client that partially inverts colors, as you can see in this screenshot: side by side comparison of emails Default dark modes: color inversion Full Color Invert is the most invasive color scheme: it not only inverts areas with light backgrounds, but also impacts dark backgrounds.
So if you've ever designed your emails to have a dark theme, this scheme will ironically force them to go light . Unfortunately, this is currently the tactic used by some of the most popular email clients, such as the Gmail app (iOS) and Outlook 2019 (Windows). In the examples below you can see that the light backgrounds have been converted to dark Image Masking Service versions of the original colors and areas that previously had a dark background with light text are now light with dark text. side by side email example Not only does this Full Color Invert scheme dramatically change your email, but email clients that use this logic also don't allow dark mode targeting at this time .
Email clients are always looking to implement dark mode as best they can and can be open to user feedback, especially since not allowing developers to target dark mode with their own styles can negatively impact readability and accessibility. In the interest of advocating for better dark mode targeting support and less invasive dark mode theme logic, you can submit your thoughts directly to Gmail's accessibility team, and you can also contribute your screenshots of Gmail dark mode breaking your email. How do I target dark mode users with my own styles? As noted above, how dark mode email clients handle your regular HTML emails varies. But what if you want to apply your own dark mode styles that could very well differ from the default email client color schemes?