New UI feedback

[tenax66]

Hi, I have some feedback on the new UI:

The "JWT Decoder" and "JWT Encoder" elements look too flat, and it took me a while to realize they were clickable buttons. This made the user experience a bit confusing.

Separating the Decoder and Encoder makes it impossible to edit the JSON directly and see the JWT update in real time. This has significantly reduced my workflow efficiency.

Thanks for your hard work—looking forward to future improvements!