Neat effort, but my one complaint is how much whitespace there is between and around various UI elements, especially in item lists such as in the Start menu and

Neat effort, but my one complaint is how much whitespace there is between and around various UI elements, especially in item lists such as in the Start menu and the sidebar of various configuration dialogs. Actual Windows XP hails from an era before visual designers all collectively decided that high information density was bad aesthetics.