制作具有两层和下拉列表的导航栏在第二层处于水平位置

So, basically, i have a navbar. I want a second "navbar" beneath, which is always visible, but without users interaction, it displays nothing. But, when you hover over a tab in the main bar, a dropdown bar starts at a given point, and goes horizontally along the second tier.So, basically, i have a navbar. I want a second