sidebar {
position: fixed;
width: 200px;
height: 100%;
top: 0;
right: 0;
background-color: f9f9f9;
padding: 20px;
box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}
window.onscroll = function() {
var sidebar = document.getElementById(”sidebar”);
sidebar.style.top = window.pageYOffset + ”px”;
};