What Is Dark Mode?

Dark Mode is a feature on mobile devices that allows your user interface to invert light colors to dark and dark colors to light. Light design elements and text are displayed against dark backgrounds.

Dark Mode was introduced to smartphones as a way to increase battery life by changing the required brightness of a screen. Some users turn to Dark Mode to make things easier on the eyes in low-light environments. Others simply prefer the aesthetics of dark color schemes.

It’s also an important change for increased accessibility to reduce eye strain and provide an improved user experience for those that have a visual impairment.

Dark mode is available on many popular apps and as an optional theme on several smartphones.

With 80% of American adults using digital devices for more than 120 minutes each day and 67% using more than two devices simultaneously, Dark Mode got popular as it allows the users to relax their eyes and work with better concentration.

Whatever your audience’s reasons for using Dark Mode, it’s important to respect their choice and provide them with a good email experience.

Clients That Let You Control Dark Mode Styles:

·      Outlook (iOS + Android)

·      Apple Mail

·      iOS Mail

·      Outlook 2019 (Mac)

·      Outlook.com

·      Superhuman

How Dark Mode Can Improve Your Deliverability

When a user configures their inbox in Dark Mode and receives an email not optimized for Dark Mode, a couple of things can happen depending on the inbox and email:

– The inbox may automatically adjust your email to be compatible with Dark Mode. This can get

messy and invert colors to the point where the email is no longer legible.

– Nothing will happen. Some inboxes only allow users to change their user interface to Dark Mode, but it doesn’t have any impact on how the actual emails render.

Your email will appear with its original light rendering, causing a poor user experience in contrast to the Dark Mode user interface. Imagine the user lying in bed at night reading their emails to suddenly be blasted in the face with bright light from your non-optimized email.

Imagine how your recipients might react to these negative inbox experiences. They might:

·      Mark your message as spam

·      Unsubscribe from your email list

·      Stop opening future emails from you

·      Delete your messages without opening them

Your deliverability is tied to recipient engagement signals like these. When inbox providers see these red flags, they may begin filtering your future email into the spam folder or completely block your messages.

However, if you design Dark-Mode-friendly emails that drive opens, clicks, and forwards, you’ll boost your sender reputation. When inbox providers notice these types of positive engagement, they’ll know your messages are wanted, increasing the likelihood they end up in the inbox.

How to Use Dark Mode Correctly

Include Transparent Images

At present, ESPs allowing for Dark Mode settings will change the colors in CSS automatically. This, however, is not true for the colors within images. Therefore, the safest bet is to have transparent backgrounds which will cause the image to change based on the background color set by the theme.

Don’ts Mix Images and Background Colors

More often than not, designers combine images and background colors in order to display buttons and design elements. This is not a good practice when it comes to dark and light optimization because background colors might change when you switch between the Dark and Light Modes, but images will not.

Have a White Stroke around the Dark Fonts

As far as fonts are concerned, it’s recommended that you add a white stroke around the darker fonts. The white stroke will be hardly visible in the lighter settings, but it will make the text more readable in Dark Mode.


Email clients are constantly changing, so whether it’s for Dark Mode or something else, it’s important to make testing your emails a routine task before you send them.

You can do this either by sending test versions of your email to each of these clients and viewing them, utilizing an email testing tool such as Litmus, or by testing email clients within your marketing tool (HubSpot’s email testing is powered by Litmus).

Advancements will come to allow for reporting on Dark Mode, and additional preview options will become available in email QA tools.

It’s ideal to start optimizing your emails for Dark Mode now, just as you would optimize your email for other elements of email accessibility.

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