July 14, 2020: Added this changelog :) Also cleaned up some mobile/tablet styling.
June 22, 2020: Fixed the bug caused by adding/removing time while the timer was running. Added basic error checking for no time entered. Added an alarm that plays when the timer is done.
June 19, 2020: Fixed an issue with the time display, where it would skip seconds or display ":60". I'm still working on fixing the bug caused by adding time while it's running.
June 12, 2020: Added some credit and disclaimer text. Made the time user-adjustable with Add/Subtract buttons. The user now also has control over the timer's pause, play, and stop behaviors.
May 21, 2020: Original version published.