Check out example codes for "w3 scroll bar". It will help you in understanding the concepts better.

Code Example 1

/* 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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