Change color of dropdown arrow?

Question

If you look at my code below, I am trying to change the color/style of the arrow on the dropdown but unable to get it working.
https://code.sololearn.com/Wn91VusN7rMl/?ref=app

Answer 1

check that, may it work:
https://stackoverflow.com/questions/611482/change-color-and-appearance-of-drop-down-arrow