Using older versions of Outlook for Mac for personal email and calendar
Hello Dan,
Greetings. Thank you for posting to Microsoft community.
I understand that you had an issue with changing the reading pane between light and dark mode which you managed to resolve by using the sun or crescent icons on the top right of the reading pane. Example in screenshot below.
Thank you for sharing with our community so that anybody who finds themselves in a similar situation may use this as a reference.
Your cooperation and kindness are much appreciated. Stay Safe!
Best Regards,
Ashraf.