Modify Broswer Scrollbar Design or Css

Modify Broswer Scrollbar Design or Css:

#Pseudo ::scrollbar element

::-webkit-scrollbar {
    width: 12px;
    background-color: #F5F5F5;
}

#Pseudo ::scrollbar-thumb element

::-webkit-scrollbar-thumb {
    -webkit-box-shadow: inset 0 0 6px rgba(0,0,0,.3); */
    background-color: #555;
}

#Pseudo ::scrollbar-track element

::-webkit-scrollbar-track {
    -webkit-box-shadow: inset 0 0 6px rgba(0,0,0,0.3);
    background-color: #F5F5F5;

}