The Spark Team 
Smart. Focused. Email.
Fast, cross-platform email designed to filter out the noise - so you can focus on what's important.
Definition
💡 Dark mode is the display setting that flips your inbox from a bright white background to a dark one, usually black or charcoal, with light-colored text. It's the same idea as dark mode on your phone, just applied to your email client.
The real reason dark mode is worth turning on
Ever check email in bed at 11 p.m. and get blasted by a white screen?
Dark mode isn't about looking cool (though, fine, it does). It reduces the glare that comes from a bright screen in a dark room, and it can meaningfully ease eye strain if you're someone who reads a lot of email late at night or early morning. On OLED phone screens, it also saves a bit of battery, since black pixels use less power than white ones.
None of this changes how your email works. It's purely visual. Your inbox, your threads, your attachments, all the same, just recolored. And if you switch between Gmail, Outlook, and Spark throughout the day, you'll notice each one handles the toggle a little differently.
Where the dark mode toggle lives in each app
Dark mode is a setting inside each app, not something that syncs automatically between them just because your phone is in dark mode.
Gmail lets you pick a theme (Default or Dark) independently of your device settings, and Google's help page covers every platform.
Outlook gives you a proper Dark mode toggle plus a separate "Black" Office theme, detailed on Microsoft's Dark Mode support page, and on iOS or Android it can follow your system setting if you choose "System Default."
Spark keeps things simple with three options: Light, Dark, or "As in System," on desktop and “system” for mobile, which is the default and just mirrors whatever your phone or computer is already set to.
One thing worth knowing: dark mode can occasionally change with how a sender's email renders. If someone sent you a white-background logo or an image with transparent edges, it might look odd against a dark background. That's on the sender's design, not something you can fix from your end. Annoying, but rare.
Some extra tips for using dark mode
Use "As in System" if you want it to just work.
Manually flipping dark mode on and off every time the sun goes down gets old fast. Let your device handle it when you are using Spark.
Turn it off temporarily if you're proofreading something visual.
Dark mode can shift how colors and contrast read, which matters if you're checking a signature, a template, or an image-heavy HTML email before sending it.
Match your composer to your reading pane.
Some clients apply dark mode to reading but not composing, or vice versa. If the mismatch annoys you, check your app's settings for a separate composer toggle.
Watch for logos that vanish in dark mode.
A transparent-background PNG designed for a white page can turn invisible, or show a faint white box, against a dark inbox. Worth checking your own signature logo in both modes, not just other people's.
Screen-sharing during a call? Switch to light mode first.
If you're walking someone through your inbox on a video call, dark mode can look muddy or hard to read on a shared screen, especially if the room lighting is bright. Small thing, but it's an easy save before a client call.