The major UI style changes to the Symbian Belle release since the Symbian Anna release are:
Supported display resolutions updated
Renewed layout introduced
Status bar
Status panel
Toolbar with graphical softkeys: Back button on left and Options on right (when softkeys are placed inside a pop-up, the softkeys are textual, as in the previous releases)
Toolbar buttons, when available, are placed between graphical softkeys
Home screen interaction and widgets
Hardware variant updates
Split-view inputs as a default input method
Flat Application menu structure