Tip calculator app

Making the tip calculator accessible for screen readers was definitely the hardest part. I originally wrapped the right section in a live region, so that the updated tip amount and total price would be properly announced. However, for some reason the screen reader would announce "Tip amount per person Total per person $4.28 $32.79" instead of "Tip amount per person $4.28 Total per person $32.79". So I ended up including the live regions inside of the dl in order to get the correct announcement. In order to test this, I used VoiceOver along with Safari, but I'm not sure about other screen readers. As always, feedback and suggestions are welcome.