Precisely, a dark theme is a cool way to read your Outlook mails if you are the kind that prefers interfaces that are less bright or if you are in a low-light environment. It is apparently available on the new Outlook.com experience only.

How do you turn on Dark Mode in Outlook?

To turn on Dark Mode, open the Quick Settings panel by selecting the Gear icon at the top of your screen. The option to enable Dark Mode is near the top of the panel, immediately under Theme selection. If your browser is unable to support Dark Mode, you should consider using Microsoft Edge. Similary, you can enable the mode in Microsoft Edge, within its settings to dial down the brightness. Open Edge and click on the menu button in the top right corner. Select Settings and under Choose a theme, select Dark from the drop-down box. You can see any email message that you receive in the original formatting by using the “Turn on the lights” button. Related Article: How to run your Windows PC in dark mode

Dark Mode is not a theme

Microsoft designed Dark Mode with an analogy that the way most people expect themes to work is different from the way the mode works. There are plans to have a dark experience for all available themes in the future, but the primary focus has been put on having something separate. Outlook’s Dark Mode only supports the default blue theme currently. There is also an explanation on why the reading pane has a dark background for email messages received.

Outlook Dark Mode vs Halloween Theme

2017’s Halloween Theme had a light gray background in the reading pane, specifically aiming at a decrease in eye strain. For the new Outlook, received email messages are recolored in a way that preserves the readability of the original message and preserves the intent of the original sender. Microsoft as well expanded the dark theme to also include the Windows 10 OS and all parts of File Explorer. This changes your windows to black, and turns your text and icons to lighter colors, making everything look more like shadows. Image: The Verge