html - 如何在没有重叠阴影的情况下进行导航

Question

这是代码的 JSFiddle:https://jsfiddle.net/93pwfrt8/

我现在的菜单是这样的:

我正在努力实现这样的目标:

由于某种原因，投资组合子菜单的阴影没有到达子菜单周围，而主菜单的阴影与子菜单重叠。

这是侧边栏的 html:

<aside>
    <nav>
        <ul>
        <li><a onclick = "$(#content).load(selector.php?content='about'); return false">About</a></li>
        <li>Portfolio
            <ul>
                <li><a onclick = "$(#content).load(selector.php?content='about'); return false">About</a></li>
                <li><a onclick = "$(#content).load(selector.php?content='about'); return false">About</a></li>
            </ul>
        </li>
        </ul>
    </nav>
</aside>

还有CSS:

html,
body {
  height: 100%;
  width: 100%;
}

nav {
  text-align: center;
}

nav ul {
  padding: 0px;
  text-align: center;
  list-style: none;
  width: 100%;
  -webkit-box-shadow: 0px 0px 25px 0px rgba(0, 0, 0, 0.9);
  -moz-box-shadow: 0px 0px 25px 0px rgba(0, 0, 0, 0.9);
  box-shadow: 0px 0px 25px 0px rgba(0, 0, 0, 0.9);
}

nav ul li {
  color: #000;
  padding: 20px;
  font: bold 12px/18px sans-serif;
  display: block;
  position: relative;
  background-color: #FFF;
  cursor: pointer;
  -webkit-transition: all 0.2s;
  -moz-transition: all 0.2s;
  -ms-transition: all 0.2s;
  -o-transition: all 0.2s;
  transition: all 0.2s;
}

nav ul li:hover {
  background: #EBEBEB;
  color: #F00;
}

nav ul li ul {
  position: absolute;
  top: 0px;
  right: -60%;
  width: 60%;
  display: none;
  opacity: 0;
  visibility: hidden;
  -webkit-transiton: opacity 0.2s;
  -moz-transition: opacity 0.2s;
  -ms-transition: opacity 0.2s;
  -o-transition: opacity 0.2s;
  -transition: opacity 0.2s;
}

nav ul li ul li {
  background: #EBEBEB;
  display: block;
  color: #fff;
  width: 100%;
}

nav ul li ul li:hover {
  background: #ABABAB;
}

nav ul li:hover ul {
  display: block;
  opacity: 1;
  visibility: visible;
  z-index: -1;
}

nav ul li>a {
  text-decoration: none;
  color: #000;
}

nav ul li:hover >a {
  color: #F00;
}

aside {
  float: left;
  position: fixed;
  width: 15%;
  clear: both;
}

我正在寻找一个解决方案，并解释我做错了什么，这样我就不会再搞砸了。

Answer 1

虽然回答晚了....但我更喜欢有点老派的方法，z-index!! :)

demo

nav ul {
  z-index:1;/*added*/
  position:relative;/*added*/
  padding: 0px;
  text-align: center;
  list-style: none;
  width: 100%;
  -webkit-box-shadow: 0px 0px 25px 0px rgba(0, 0, 0, 0.9);
  -moz-box-shadow: 0px 0px 25px 0px rgba(0, 0, 0, 0.9);
  box-shadow: 0px 0px 25px 0px rgba(0, 0, 0, 0.9);
}


nav ul li ul {
  position: absolute;
  top: 0px;
  right: -60%;
  width: 60%;
  display: none;
  opacity: 0;
  z-index:999; /*added*/
  visibility: hidden;
  -webkit-transiton: opacity 0.2s;
  -moz-transition: opacity 0.2s;
  -ms-transition: opacity 0.2s;
  -o-transition: opacity 0.2s;
  -transition: opacity 0.2s;
}