Nice job! It’s a very clean look, and it mostly behaves like a calculator should. There are two things I noticed:
When hovering over any of the buttons, the size of the whole calculator changes. It makes it dance as I’m inputing numbers.
I can input more than one operator or decimal point in a row. A challenging improvement would be to disallow more than one non-numeric character while still allowing the user to input an expression with multiple operators.
One thing I noticed was that I could have more than one symbol. So for example you could have 1++++++1 which would equal 2 correctly though.
Thanks. I’ll try to implement these.