Summary
To help reduce eye strain Outlook for mobile now has a dark mode option.
To enable this, make sure you have the latest version of the app.
Then in the app select your profile icon to get to the folder selector, you should then be able to see a cog/gear icon for settings, select that.
Towards the bottom of the settings there is a toggle switch for dark mode.
Further Information
If you have any questions about or need assistance then please contact the GCC Group Support Team on 0845 260 1151 or servicedesk@gccgroup.co.uk