当文本到达右边框时，向下移动侧边栏中的“a”代码段中的文本

<div id="sidebar">
  <!-- 这里是侧边栏中的文本 -->
  Lorem ipsum dolor sit amet, consectetur adipiscing elit.
</div>

#sidebar {
  position: fixed;
  top: 0;
  right: 0;
  width: 200px;
  height: 100%;
  background-color: #f1f1f1;
  overflow-y: scroll;
}

window.addEventListener('scroll', function() {
  var sidebar = document.getElementById('sidebar');
  var sidebarRect = sidebar.getBoundingClientRect();
  var sidebarBottom = sidebarRect.top + sidebarRect.height;
  var windowBottom = window.innerHeight;

  if (sidebarBottom > windowBottom) {
    sidebar.style.transform = 'translateY(-' + (sidebarBottom - windowBottom) + 'px)';
  } else {
    sidebar.style.transform = 'translateY(0)';
  }
});