CSS3 scrollbar styling on a div

Setting overflow: hidden hides the scrollbar. Set overflow: scroll to make sure the scrollbar appears all the time.

To use the ::webkit-scrollbar property, simply target .scroll before calling it.

.scroll {
   width: 200px;
   height: 400px;
    background: red;
   overflow: scroll;
}
.scroll::-webkit-scrollbar {
    width: 12px;
}

.scroll::-webkit-scrollbar-track {
    -webkit-box-shadow: inset 0 0 6px rgba(0,0,0,0.3); 
    border-radius: 10px;
}

.scroll::-webkit-scrollbar-thumb {
    border-radius: 10px;
    -webkit-box-shadow: inset 0 0 6px rgba(0,0,0,0.5); 
}
​

See this live example