Apple Working on Redesigned iCloud Mail for Web

Apple has begun testing a major redesign to the iCloud Mail experience on the web, bringing its webmail service more in line with recent design changes made in macOS Big Sur.
The new design, currently in beta, reported first by 9to5mac, features a cleaner overall design and feel than the current public experience of ‌iCloud‌ Mail for the web. The current, soon-to-be previous version features thin typography, lighter colors, and design elements from iOS 7. Additionally, the new design a