When trying to add the class feat gained from Natural Ambition I am unable to scroll passed the first page to select the desired feat.
Over all first impressions: It is clean and very easy to understand. The character sheet output looks clean as well which is better than Hero Lab’s output. It is a little slow in transition from page to page but given this is an Alpha I would consider it understandable.
Having formerly used DnD Beyond I can say it is easier to understand at first impressions so keep up the good work. Simple and clean seem to be your focus and it will work for you!