Reminder: make sure to update to the latest version of the Activity Manager component.
The new Activity Manager card aims to be more flexible and easier to interact with.
First, the card applies more of a Material theme to be consistent with the rest of the Home Assistant dashboard:
Next, the add screen was completely re-worked into a dialog. When creating the activity, you can set when you last did it and you now get an icon picker:
Finally, you can set the date and time when updating an activity so you can log it correctly: