https://www.bleepingcomputer.com/news/microsoft/microsoft-s-dark-mode-for-outlook-on-the-web-will-launch-soon/

A dark mode for Outlook.com is one of the most highly requested features and last year at Halloween Microsoft teased a prototype version of its web mail service with a dark theme.

Microsoft has been working on a new dark mode for Outlook.com for the past few months and now the software maker is getting ready to roll it out to its web mail service users soon.