Mac Calculator App

To design a calculator was the prompt for day 4 of the Daily UI challenge.

I decided to venture off into desktop apps, and quickly realized users with keyboards would rather type in their mathematical queries than press buttons on the screen like in the traditional Mac OS calculator app.

This also allowed me to design an app that could do much more than traditional simple calculators, as there was nothing stopping me from allowing them to input Wolfram Alpha style mathematical questions.

Please give me your feedback on this design. It's not my first calculator, but it is my first attempt to design a native desktop application.