Check out example codes for "how to change style of scrollbar in html". It will help you in understanding the concepts better.

Code Example 1

::-webkit-scrollbar{width:6px;border-left:1px solid #E6ECF8;}
::-webkit-scrollbar-thumb{background-color:#d6872c;}

Code Example 2

/* width */
::-webkit-scrollbar {
  width: 10px;
}

/* Track */

  ::-webkit-scrollbar-track {
  background: #f1f1f1; 
}

/* Handle */

  ::-webkit-scrollbar-thumb {
  background: #888; 
}

  
/* Handle on hover */
::-webkit-scrollbar-thumb:hover {
  
  background: #555; 
}

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