Apparently this is already available in the iOS app, but not on the site or Android app.
The ability to reset rank to the order we chose is badly needed. If I delete 50 entries in a list the rank numbers should reflect that (eg 200 in a list, delete 50, new rank numbers 1-150, new entries are then 151,152,153, etc). Instead it leaves blank rank numbers somewhere in the middle and new entries get stuck in there (so rank numbers 1-200 still rather than 1-150, new entries 132,133,134, etc) . Please add the ability to reset rank or fix the bug that causes rank numbers to become out of order.
As an aside, the option to go back to the old theme please. The purple is quite literally giving me migraines