CSS 弯曲渐变和框阴影

Question

Can CSS be used to make a left and right edges of a content container look like this image? I have been trying to figure out a way to do this without using an image, if that is possible.

Here is jsFiddle that I have been working on. The CSS for the "top" class never gets applied. The CSS for the "bottom" class seems to work ok though.

http://jsfiddle.net/kXuQY/

HTML:

<div class="drop-shadow top bottom">
  Content here.
</div>

CSS:

.drop-shadow {
/** Create container.  Box-shadow here is to color the inside of the container **/
 position:relative;
 width:50%;
 background: none repeat scroll 0 0 #FFFFFF;
 box-shadow: 0 1px 4px rgba(0, 0, 0, 0.3), 0 0 40px rgba(0, 0, 0, 0.1) inset;
 padding:3em;
 margin: 2em 20px 4em;
 text-align:center
}

.top:before,
.top:after {
  /** Generate pseudo-elements ('before' and 'after') and push them behind the container box. Position pseudo-elements ('before', and 'after') and give them dimensions **/
 content:"";
 position:absolute;
 z-index:-1;
 top:20px;
 left:0;
 width:40%;
 height:1em;
 max-width:150px;
 -webkit-box-shadow:0 15px 10px rgba(0, 0, 0, 0.7);
 -moz-box-shadow:0 15px 10px rgba(0, 0, 0, 0.7);
 box-shadow:0 15px 10px rgba(0, 0, 0, 0.7);
 -webkit-transform:rotate(70deg);
 -moz-transform:rotate(70deg);
 -o-transform:rotate(70deg);
 transform:rotate(70deg);
}

.top:after{
  /**One of the pseudo-elements then needs to be positioned on the other side of the element and rotated in the opposite direction. This is easily done by overriding only the properties that need to differ **/
 right:0;
 left:auto;
 -webkit-transform:rotate(-70deg);
 -moz-transform:rotate(-70deg);
 -o-transform:rotate(-70deg);
 transform:rotate(-70deg);
}

.bottom:before,
.bottom:after {
  /** Generate pseudo-elements ('before' and 'after') and push them behind the container box. Position pseudo-elements ('before', and 'after') and give them dimensions **/
 content:"";
 position:absolute;
 z-index:-2;
 top:90px;
 left:0;
 width:10%;
 max-width:150px;
 -webkit-box-shadow:0 15px 10px rgba(0, 0, 0, 0.7);
 -moz-box-shadow:0 15px 10px rgba(0, 0, 0, 0.7);
 box-shadow:0 15px 10px rgba(0, 0, 0, 0.7);
 -webkit-transform:rotate(99deg);
 -moz-transform:rotate(99deg);
 -o-transform:rotate(99deg);
 transform:rotate(99deg);
}

.bottom:after{
  /**One of the pseudo-elements then needs to be positioned on the other side of the element and rotated in the opposite direction. This is easily done by overriding only the properties that need to differ **/
 right:0;
 left:auto;
 -webkit-transform:rotate(-99deg);
 -moz-transform:rotate(-99deg);
 -o-transform:rotate(-99deg);
 transform:rotate(-99deg);
}

Answer 1

You can use ::before and ::after pseudo elements to achieve the effect, see here .

Example: ( Demo )

HTML:

<div id="box">
<h1>css-3-box-shadow</h1>
<p>some text</p>
</div>

CSS:

#box:before, #box:after {
    background: none repeat scroll 0 0 rgba(0, 0, 0, 0.7);
    bottom: 15px;
    box-shadow: 0 15px 10px rgba(0, 0, 0, 0.7);
    content: "";
    left: 10px;
    max-width: 300px;
    position: absolute;
    top: 80%;
    transform: rotate(-3deg);
    width: 50%;
    z-index: -1;
}

#box:after {
    left: auto;
    right: 10px;
    transform: rotate(3deg);
}

#box {
    background: none repeat scroll 0 0 #DDDDDD;
    border-radius: 4px 4px 4px 4px;
    color: rgba(0, 0, 0, 0.8);
    line-height: 1.5;
    margin: 60px auto;
    padding: 2em 1.5em;
    position: relative;
    text-shadow: 0 1px 0 #FFFFFF;
    width: 60%;
}