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It’s a topic that’s been keeping email geeks up at night for years now... Dark mode email design and development. As if you didn’t have enough to deal with when it comes to email rendering.

Dark mode throws yet another wrench in the gears of email development. However, if you know what you’re doing, you can optimize the inbox experience for both light and dark mode emails.

If you’re ignoring dark mode, it’s likely that some of your subscribers are opening your HTML email designs only to find an unreadable mess. So, let's shed some light on this shadowy subject and explore how to create emails that look great, no matter the mode.

What is dark mode anyway?

Dark mode is a display setting that can be turned on and off for many devices, applications, and operating systems. Essentially, it changes the user interface so that instead of seeing the traditional dark text on a light background, there’s light text on a dark background.

So a background with hex code #FFFFFF and text color hex code of #000000 switches.

In dark mode, the background hex code becomes #000000 and the text hex code switches to #FFFFFF.

Here’s how that might look when viewing an email in light or dark mode on a mobile device:

Dark mode UI was the norm back in the ‘70s not long after email was invented. Picture those old, boxy PCs with black screens and glowing green text. Light mode eventually became the standard along with LCD screens in the ‘90s.

Twitter and YouTube were among the first popular services to offer dark mode. In 2019, Microsoft, Google, and Apple followed the trend and began offerring dark or “night mode” options for their programs and operating systems.

In 2023, Twitter/X made the move to make its dark mode UI the default. At first, Elon Musk said it would be the only option. Apparently, he believes dark mode is “better in every way.” But backlash from users prompted the company to bring back a light mode setting for the platform.

Once Gmail, Apple Mail, and Outlook started offering dark mode, email marketers began paying attention too. Here’s how an old Email on Acid newsletter looked when we first started testing our own stuff in dark mode four years ago. It’s not terrible. But it’s not ideal either.

Why dark mode matters in email

Remember when dark mode was just a niche preference? Those days are long gone. Dark mode has rapidly become a mainstream feature, with recent studies showing that a significant portion of users prefer dark mode for at least some of their digital interactions.

Of course, those studies on consumer usage of dark mode settings vary. What you really want to know is how many of the contacts on your list are opening messages in dark mode. Advanced Email Analytics from Sinch Email on Acid let you do exactly that. Find out more about tracking dark mode opens on our platform.

But we digress... Why do people love dark mode so much? Let's break it down:

1. Eye comfort: Many users find dark mode easier on the eyes, especially in low-light conditions. This can be particularly beneficial for those who check their emails late at night or first thing in the morning.
2. Reduced blue light exposure: Some studies suggest that reducing exposure to blue light, especially in the evening, can help with sleep patterns. Dark mode is one way users try to achieve this.
3. Battery life: For devices with OLED screens, dark mode can significantly extend battery life. This is because OLED screens can turn off individual pixels when displaying black, consuming less power.
4. Aesthetic preference: Let's face it, some people just think dark mode looks cool. It can give a sleek, modern feel to interfaces.
5. Reduced screen glare: In certain lighting conditions, dark mode can help reduce screen glare, making it easier to read content.

Whatever the reason, there's a good chance a significant portion of your subscribers are viewing your emails in dark mode. As email professionals, it's our job to ensure our messages look great in both light and dark environments.

The challenges of dark mode emails

Before we jump into solutions, let's break down the main challenges of dark mode emails. Understanding these hurdles is the first step in overcoming them:

Color inversion in dark mode: When your design flips

One of the primary challenges with dark mode is color inversion. Many email clients automatically invert colors when switching to dark mode, turning light backgrounds dark and dark text light. While this sounds simple in theory, in practice it can lead to some unexpected results:

• Your carefully chosen color scheme might be completely altered, affecting the overall look and feel of your email.
• Important design elements, like buttons or call-to-action areas, might lose their impact or become difficult to distinguish.
• Subtle color differences that worked well in light mode might become indistinguishable in dark mode.

In this example, purple may be a primary brand color you use for calls-to-action in emails. But the inverted green button may not fit your brand at all.

Brand consistency in dark mode: Logo visibility issues

Your brand's visual identity is crucial in email marketing. However, dark mode can mess up your email branding efforts:

• Logos designed to stand out on a light background might suddenly become invisible on a dark background.
• Brand colors carefully chosen for light backgrounds might clash or become unreadable when inverted.
• The overall "feel" of your email might shift dramatically, potentially disconnecting it from your brand's usual aesthetic.

Here's what can happen if your logo isn't optimized for viewing emails in dark mode:

For a bunch of options on how to handle this, check out our tips on fixing dark mode logo problems.

Accessibility and dark mode: Unexpected contrast issues

While dark mode can benefit some users with visual impairments, it can also create unexpected email accessibility issues:

• Color contrasts that worked perfectly in light mode might become problematic in dark mode.
• Text that was easily readable on a light background might become strained on a dark background, especially if the font weight isn't adjusted.
• Important visual cues or separators might disappear or become less noticeable in dark mode.

Email clients and dark mode rendering

Like usual in the world of email development, it’s never as simple as having a dark mode and non-dark mode, all email clients that feature dark mode will handle it slightly differently.

As explained in this excellent article from our friends at Parcel, you can break down the different dark modes to three different modes; full inversion, partial inversion and no change.

Full inversion will change both your font colors and your backgrounds, partial inversion is very similar but will largely leave your backgrounds untouched, no change won’t inverse any of your content.

Email Client	Auto-Inverts Colors?	Common Dark Mode Challenge
Apple Mail (iPhone/iPad)	Yes	Auto inverts when the background is transparent or pure white (#ffffff).
Apple Mail (macOS)	Yes	Auto inverts when the background is transparent or pure white (#ffffff).
Outlook (iOS)	Partially	May make background color darker.
Outlook (macOS)	Partially	The only Outlook option that does support @media (prefers-color-scheme). May make background color darker.
Outlook (Windows)	Yes	The only Outlook option that consistently auto-inverts colors.
Outlook.com (webmail)	Partially	The only Outlook option where image swap works. May make background color darker.
Gmail (Android)	Yes (when not already dark)	Does not support the query @media (prefers-color-scheme).
Gmail (webmail)	No	Does not support the query @media (prefers-color-scheme).
AOL (webmail)	No	No current dark mode user interface.
Yahoo! (webmail/app)	No	Does not support the query @media (prefers-color-scheme).

Apple Mail and dark mode

In Apple Mail's dark mode, it tends to invert pure black (#000000) and pure white hex (#FFFFFF) codes. Apple Mail will completely disregard contrast or other-such rules if you have those hex codes and invert them regardless.

We advise to choose slightly different hex codes, such as #000001 or #FFFFFE, the difference in color is not noticeable and it’ll help you avoid any surprises.

Gmail and dark mode

As is often the case, Gmail can often throw a bit of a curveball when it comes to how it handles our dark mode emails, simply because there are so many versions of Gmail, ranging from iOS to Android to regular old Gmail, nailing down a solution can be quite tough. Previewing your campaigns in dark mode on Gmail helps you understand how to build the best experience for those subscribers.

If you’re struggling with Gmail on iOS dark mode, you can try this insanely clever solution by Rémi Parmentier, utilizing blends (which are supported in Gmail) to control how your email looks when dark mode has its way.

Outlook and dark mode

Ahh, now we get to it, the elephant in the room; Outlook. One significant issue is how Outlook handles color inversions. In dark mode, where backgrounds become dark and text becomes light, Outlook might struggle to accurately invert colors, leading to unexpected and sometimes undesirable outcomes. This can result in poor readability, visual inconsistencies, and an overall less-than-ideal user experience.

Additionally, Outlook's dark mode implementation might not fully align with standard development practices, introducing quirks and challenges for email developers. These issues can range from the rendering of background images to the handling of certain styles, making it crucial for email designers to employ specific strategies to ensure their emails look as intended in Outlook's dark mode.

If you’re struggling to get text readable in Outlook, Nicole Merlin has an amazing guide on tackling font colors in Outlook’s Dark Mode, includin

Illuminating solutions for dark mode emails

Now that we've outlined the challenges, let's dive into some strategies to help you navigate the murky waters of dark mode email design:

Setting the stage for dark mode: Meta tags and CSS

The first step in creating dark mode-friendly emails is to tell email clients that your email supports both light and dark modes. You can do this by adding specific meta tags to the <head> section of your email:

<meta name="color-scheme" content="light dark">
<meta name="supported-color-schemes" content="light dark">

These meta tags essentially say, "Hey, email client! This email is designed to work in both light and dark modes."

To complement these meta tags, you should also include the following in your CSS:

<style type="text/css">
  :root {
    color-scheme: light dark;
    supported-color-schemes: light dark;
  }
</style>

This CSS reinforces the message that your email supports both color schemes.

Detecting and adapting to dark mode: Media queries

Once you've set the stage, you can use CSS media queries to detect when dark mode is active and adjust your styles accordingly. Here's an example:

@media (prefers-color-scheme: dark) {
  body {
    background-color: #1a1a1a !important;
    color: #ffffff !important;
  }
  h1, h2, h3, p {
    color: #f1f1f1 !important;
  }
}

This media query says, "If dark mode is on, use these colors instead." It's a powerful tool that allows you to create a tailored dark mode experience.

However, it's important to note that not all email clients support this feature. It works great in email clients that support media queries, like Apple Mail and Outlook for Mac. But some clients, like Gmail, don't support this feature, so you'll need to have fallback options.

Making your logo visible in dark mode: Image swapping techniques

Your logo is a crucial part of your brand identity. So, ensuring it's visible in both light and dark mode is essential. Here are some strategies:

• Use transparent PNGs: This can work well, but be cautious of dark text or elements disappearing against a dark background.
• Add a light outline or glow: This can help your logo stand out in both modes but be sure it doesn't affect the logo's appearance in light mode.
• Create a dark mode version of your logo: This is often the best solution. You can use image swapping techniques to show different versions based on the mode.

Here’s how the code might look if we wanted to display different logos in dark and light mode:

CSS:

  @media (prefers-color-scheme:dark) {
          .dark-mode-hide{
              display:none!important;
     }
     .dark-mode-show{
  display:block!important;
  }
        } 

HTML

  <img src="https://marketing.emailonacid.com/hubfs/NORMAL-EoA-Logo.png" width="150" alt="Email on Acid" border="0" style="display:block;max-width:150px;font-family:Arial,sans-serif;font-size:9px;line-height:12px;color:#ffffff;font-weight:bold;" class="dark-mode-hide">

  <!--[if !mso]><!-->
  <img src="https://marketing.emailonacid.com/hubfs/images/logos/DARK-MODE-EOA-Logo.png" width="150" alt="Email on Acid" border="0" style="display:none;max-width:150px;font-family:Arial,sans-serif;font-size:9px;line-height:12px;color:#ffffff;font-weight:bold;" class="dark-mode-show">
  <!--<![endif]-->  

Note: the code under <!–[if !mso]><!–> is Microsoft Office conditional code that tells Outlook to ignore the dark mode logo. With Outlook,  you can also use the tag “mso-hide:all” to keep elements hidden in dark or light modes.

This code tells email clients to use the dark mode logo when dark mode is active, and the light mode logo when it's not. You can use this same technique for other important graphics in your email design.

Of course, there are simpler solutions, like the glow or outline trick.

Here's how the Sinch Email on Acid logo would display in dark mode with a white stroke that outlines text and fills in gaps (Note: Graphic designers often hate this technique):

Optimizing images for dark mode emails

Images play a crucial role in many email campaigns, but they can be tricky to handle in dark mode. Here are some tips, many of which are similar to handling dark mode logos:

• Use transparent backgrounds: This allows your images to blend seamlessly with both light and dark backgrounds. Otherwise, you could get an unsightly white background around images in dark mode.
• Add a subtle outline: For images that might get lost on a dark background, consider adding a light outline.
• Create dark mode versions: For key images, you might want to create dark mode-specific versions and use the image swapping technique we discussed for logos.

Ensuring accessibility in dark mode emails

Email accessibility should always be a priority in your design choices, and dark mode adds an extra layer to consider:

• Check contrast ratios: Use tools to ensure your text meets WCAG guidelines for contrast in both light and dark modes.
• Use sufficient font sizes: Smaller text can be harder to read in dark mode, so err on the side of larger, clearer fonts.
• Don't rely solely on color: Use other visual cues (like icons or underlines) to convey information, not just color differences.
• Test with screen readers: Ensure your dark mode optimizations don't interfere with screen reader functionality.

Handling dark mode across different email clients

Given the inconsistent implementation of dark mode across email clients, it's crucial to have a strategy:

• Design for the lowest common denominator: Ensure your email looks good in clients that don't support dark mode or advanced CSS.
• Use progressive enhancement: Layer on dark mode optimizations for clients that support them.
• Test extensively: Use tools like Sinch Email on Acid to preview your email across different clients and modes.
• Have fallback options: For elements crucial to your message, consider providing alternatives that work in all scenarios.

Best practices for dark mode email design

Now that we've covered the technical aspects, let's look at some overall best practices for designing dark mode emails:

• Start with dark mode in mind: Don't treat dark mode as an afterthought. Consider it from the beginning of your design process. If you have an email design system, dark mode should be part of it.
• Use a dark mode color palette: Develop a set of colors that work well in dark mode and align with your brand.
• Avoid pure black backgrounds: Very dark greys are often easier on the eyes than pure black.
• Be careful with shadows: Shadows that look great in light mode might disappear in dark mode.
• Test, test, test: Always preview your emails in both light and dark mode across various clients and devices.

Testing: The key to dark mode email success

Here's where we put on our problem-solving hat. Testing your emails in dark mode across different clients is crucial. That's where Sinch Email on Acid comes in handy. Our email quality assurance platform lets you test and preview your emails in dark mode across various clients and devices, helping you catch rendering issues before they reach your subscribers.

With Sinch Email on Acid, you can:

• Preview your email in both light and dark mode
• Test across multiple email clients and devices
• Identify and fix rendering issues quickly
• Ensure your emails look great for all subscribers, regardless of their mode preference

Plus, track dark mode email opens in with our analytics so you can see exactly why optimizing for dark and light mode is worth the effort.

Don't be afraid of the dark (mode)

Dark mode in email doesn't have to be a headache. With these tips, techniques, and testing strategies, you can create emails that look great whether your subscribers prefer the light side or the dark side.

Remember, the key to mastering dark mode emails is thorough testing and a willingness to adapt your design process. By considering dark mode from the start, using the right tools and techniques, and testing thoroughly, you can ensure your emails shine in any setting.

So go ahead, email pros! Embrace the challenge of dark mode and create emails that look fantastic no matter how they're viewed. And when in doubt, test it out with Sinch Email on Acid. Your subscribers (and your peace of mind) will thank you.

More dark mode email resources

Dark mode is an ever-evolving problem that email developers are tackling every day and new and exciting solutions are cropping up all the time. It’s impossible for us to cover everything about dark mode in just one article, so we have a great selection of other resources.

• Video: Email After Dark: Coding For Dark Mode
• Video: How To Prepare Your Email Design System for Dark Mode
• Webinar: Expert Advice: Designing Dark Mode Emails
• Article: Dark Mode vs. Light Mode: Which Is Better?
• Article: How to resolve issues with email dark mode