如何制作体积阴影 css

How to make volume shadow css

如何制作这样的阴影(图片示例)。我试过 after 伪元素,带有半径和剪辑,但结果还差得远。

.page{
  width: 100%;
  display: flex;
  justify-content: center;
  min-height:100%;
  background: #ebebeb;
  padding-top: 100px;
  padding-bottom: 100px;
}

.sidebar{
  width: 260px;
  height: 500px;
  background: #ebebeb;
  position: relative;
}

.sidebar::after{
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    height: 500px;
    right: 0;
    width: 40px;
    box-shadow: 5px 0 20px 0 rgba(0, 0, 0, 0.4);
    display: block;
    border-radius: 50% / 20px;
    clip: rect(auto, 80px, auto, 40px);
}
<div class="page">
  
  <div class="sidebar">Sidebar</div>
  
  <div class="content"></div>
  
</div>

只把盒子阴影放在右边怎么样:

.page{
  width: 100%;
  display: flex;
  justify-content: center;
  min-height:100%;
  background: #ebebeb;
  padding-top: 100px;
  padding-bottom: 100px;
}

.sidebar{
  width: 260px;
  height: 500px;
  background: #ebebeb;
  box-shadow: 15px 0 15px -15px rgba(0, 0, 0, 0.8);
}
<div class="page">
  
  <div class="sidebar">Sidebar</div>
  
  <div class="content"></div>
  
</div>

如果你需要在伪元素上:

.page {
  width: 100%;
  display: flex;
  justify-content: center;
  min-height: 100%;
  background: #ebebeb;
  padding-top: 100px;
  padding-bottom: 100px;
}

.sidebar {
  width: 260px;
  height: 500px;
  background: #ebebeb;
  position: relative;
}

.sidebar:after {
  content: '';
  display: block;
  position: absolute;
  top: 0;
  bottom: 0;
  left: 100%;
  width: 50px;
  transform: translateX(-50px);
  box-shadow: 15px 0 15px -15px rgba(0, 0, 0, 0.9);
}
<div class="page">

  <div class="sidebar">Sidebar</div>

  <div class="content"></div>

</div>

有更多的曲线(但需要一个内部元素)

.page {
  width: 100%;
  display: flex;
  justify-content: center;
  min-height: 100%;
  background: #ebebeb;
  padding-top: 100px;
  padding-bottom: 100px;
}

.sidebar {
  width: 260px;
  height: 500px;
  position: relative;
}


.sidebar .inner {
  min-height:100%;
  background: #ebebeb;
  position: relative;
  z-index:2;
}

.sidebar:after {
  content:'';
  position: absolute;
  z-index:1;
  bottom: 3%;
  left:100%;
  transform: translateX(-18px);
  width: 15px;
  height: 94%;
  background: #999999;
  border-radius: 15px / 100%;   
  box-shadow: 0 0 10px 10px #999999; 
}
<div class="page">

  <div class="sidebar"><div class="inner">Sidebar</div></div>

  <div class="content"></div>

</div>

body ,html {
  height:100%;
}

.page{
  width: 100%;
  height:100%;
  background: #ebebeb;
  display:flex;
  flex-direction: row;
  justify-content: center;
}

.sidebar{
  width: 260px;
  background: #ebebeb;
  position: relative;
  left:0;
  top:0;
  height:100%;
  box-shadow:5px 0px 5px #cacaca;
}


.content {
    width: calc(100% - 260px);
    padding-left: 25px;
    background-color: #dedede;
}
<div class="page">
  
  <div class="sidebar">Sidebar</div>
  
  <div class="content">Content</div>
  
</div>