A guest with dark mode switched on may see your campaign with inverted colours, a logo that has vanished into a black background, or text you did not choose. This is decided by their device and email app, not by Bookboost, so you cannot switch it off for them. What you can do is design so it holds up either way.
Two different things called dark mode
These are easy to confuse, and only one of them affects your guests.
The dark mode toggle in Bookboost is a preview feature in the campaign builder. It shows you how the email might look on a dark background. Turning it on or off changes nothing about how the email is delivered.
Dark mode on the guest's device is the real one. Their phone or email app decides how your message is rendered when they open it.
So a guest with dark mode active can receive your campaign in a dark theme even though you never enabled anything.
What colour inversion does
Dark mode can invert colours unpredictably. Light or white backgrounds may become dark or black, and text and background colours can flip to their opposites. The result varies by client, which is why it is difficult to guarantee an identical result for every recipient.
Designing so it works either way
There is no setting in Bookboost that forces dark mode on or off for your guests. These are the practical steps that help.
Use logos and images with transparent backgrounds, so they do not sit in a white box on a dark background.
Avoid pure white and pure black as background colours, since those are the ones most aggressively inverted.
Keep enough contrast between text and background that the message stays readable if the two swap.
Add a visible border or outline around logos that would otherwise disappear against a dark background.
Test on a real device with dark mode on, not only in the builder preview.
What this does not do
You cannot control whether a guest sees your email in dark mode. That is their device setting.
The Bookboost preview toggle approximates the effect. It is not a guarantee of how any particular client will render the message.
Different email clients invert differently, so an email that looks right in one dark-mode client may still shift in another.
Getting help
Open Talk to Us in the left menu of the platform, or email support@bookboost.io. Tell us the campaign name, the device, and the email app where you saw the problem.