Can’t see new incoming email since upgrading to Thunderbird 78.4

Upgraded my Thunderbird from 68xx to 78.4 yesterday. When opening Thunderbird today I cannot see any of my new email. Thunderbird is properly downloading them from Comcast POP3 and when I mouse-over any of the new emails I can see them very faintly in white font on white background. As expected I get my visual/audio pop-up warning when new email comes in but the entire incoming mail pane in the inbox is white space. I can see previously read email in my inbox I received before the “upgrade”, however, the email I am viewing used to be highlighted and now the highlighting is gone as well. I tried doing the “repair” on the inbox to no avail. Am running Windows 10. Have spent hours trying to figure this out. Would appreciate any help available. Thanks. John