/* 弹窗过长时，在弹窗白色内容区域内滚动；标题和关闭按钮保持可见。 */
.ad-popup{
  max-height:calc(100dvh - 28px);
  box-sizing:border-box;
  display:flex;
  flex-direction:column;
}
.ad-popup h2{flex:0 0 auto;padding-right:52px}
.ad-content{
  min-height:0;
  flex:1 1 auto;
  overflow-y:auto;
  overscroll-behavior:contain;
  -webkit-overflow-scrolling:touch;
  touch-action:pan-y;
}