Indexhibit Support

hi, folks.

when I right click and drag, usually transparent blue box occurs.
But can I change the color of that? i don't even know how to call it though.

here is the reference website. please take a look.

wedonotsleep.com/fatboy-lights-up-the-room/

Thank you in advance,

That is a default browser behavior - it's not something we can control.