how to create a moving and flashing star

Hi, everyone.
  I just started using react spring，I'm not familiar with its usage.
  I have a question. I don't know what to do

  demo: https://codesandbox.io/s/hardcore-rosalind-0tjvf?file=/src/App.js

  when not moving, it flashing, but when moving, flashing(opacity) not work

