Need feedback for my basic calculator

Hi guys,

I need your feedback to my basic calculator web page exercise. I still need time to lay it out in CSS. I need time because I have not tried laying out in CSS. At the moment, it is just in text and button elements that are not aligned yet. The calculator also support typing the input.

Codepen: https://codepen.io/claive-alvin-polo-acedilla/pen/wvBJENg
Github: https://github.com/cabpacedilla/boyet/blob/master/calculator