Segue o script para deixar sua barra de rolagens colorida.
<style type="text/css">
body{
scrollbar-face-color: #003366;
scrollbar-highlight-color: #000000;
scrollbar-shadow-color: #000000;
scrollbar-3dlight-color: #666666;
scrollbar-arrow-color: #000000;
scrollbar-track-color: #999999;
scrollbar-darkshadow-color: #999999
}
</style>