It's not offline or open source but I love Qube Money. No transactions to import because you choose category to spend from before you can swipe your Debit Card.

It's not offline or open source but I love Qube Money. No transactions to import because you choose category to spend from before you can swipe your Debit Card. For regular bills I still use a separate account/CC but this has allowed me and my SO to spend a lot less time budgeting.