how to change the color of a dropdown menu thing!!

i couldn't find anyone that had posted how to do this (but i somehow managed to figure it out #womeninstem) but i saw other ppl asking this too so i figured id post this!! this is for the little dropdown menu thingy you can put stamps, blinkies, quiz results, whatever under - i made it white but you can change the color to whatever you want <3

<details><summary style="font-size: 13px;" class="mb8">TITLE </summary>

CONTENT