二级垂直菜单在悬停时消失-Secondlevelverticalmenudisapperaswhilehovering

Remove margin-left: 25px; from .dropdown-submenu > .dropdown-menu

删除margin-left:25px;来自.dropdown-submenu> .dropdown-menu

It disappears because when you try to hover into the second menu you run into that margin so you leave the initial element that maintains the hover state. Use padding instead.

它会消失,因为当您尝试将鼠标悬停在第二个菜单中时会遇到该边距,因此您将保留维持悬停状态的初始元素。改用填充。

Inspect the element with developer tools (right-click > Inspect) to better visually see the area around the element.

使用开发人员工具检查元素(右键单击> Inspect)以更好地直观地查看元素周围的区域。