How to give scrollbars a custom style?

Design help General
4

I pasted this in the head code, and oddly it doesn’t do anything. Is there something more one would need to know to use this?

I usesd following code, just pasted it into the head code and it works fine.

<style>
::-webkit-scrollbar
{
  width: 12px;  /* for vertical scrollbars */
  height: 12px; /* for horizontal scrollbars */
}

::-webkit-scrollbar-track
{
  background: rgba(0, 0, 0, 0.1);
}

::-webkit-scrollbar-thumb
{
  background: rgba(0, 0, 0, 0.5);
}
</style>