Add shadow to custom shape made with border in CSS

Question

Ok, so in HTML I have one div tag with a before and after pseudo elements. This is my CSS:

.divClass{
    background: #41423D;
    height:30px;
}
.divClass:before{
    content: '';
    line-height: 0;
    font-size: 0;
    width: 0;
    height: 0;
    border-width :15px 7px 15px 7px;
    border-color: transparent #41423D #41423D transparent;
    border-style:solid;
    position: absolute;
    top: 0;
    left: -14px; 
}
.divClass:after{
    content: '';
    line-height: 0;
    font-size: 0;
    width: 0;
    height: 0;
    border-width :15px 7px 15px 7px;
    border-color: transparent transparent #41423D #41423D;
    border-style:solid;
    position: absolute;
    top: 0;
    right: -14px;
}

So, in design it becomes like this:

 ___ 
/   \

Now all I need is a shadow on the before and after pseudo elements which are the 2 triangles on either side of the div. The pseudo elements have 0 width and height so using box-shadow is a little tricky.

I need the shadow along the triangle. So, what can I do?

Answer 1

You can use unicode character : ▲ to make the triangles.

Apply a text shadow on it.

If the shape of the triangle is not what you want you can adjust it with transform: rotate(); or transform: skewX(); or both.

It's a bit tricky and not perfect but it can works :

span {
  display: inline-block;
  font-size: 70px;
  transform: skewX(29.5deg);
  color: red;
  text-shadow: 2px 2px 4px gray;
}

<span>▲</span>

There are some other possibilities, all describe on a CSS Tricks post, so check it if you want :

https://css-tricks.com/triangle-with-shadow/

If think you can check filter: drop-shadow() too. In case you do not need a support for all the browsers it may works for you...

edit:

According to the css tricks post, can't you do that ?

.triangle-with-shadow {
  transform: rotate(-45deg);
  width: 100px;
  height: 100px;
  position: relative;
  overflow: hidden;
  box-shadow: 0 20px 10px -17px rgba(0, 0, 0, 0.5);
}
.triangle-with-shadow:after {
  content: "";
  position: absolute;
  width: 50px;
  height: 50px;
  background: #999;
  transform: rotate(45deg); /* Prefixes... */
  top: 75px;
  left: 25px;
  box-shadow: -1px -1px 10px -2px rgba(0, 0, 0, 0.5);
}

<div class="triangle-with-shadow"></div>

Another possibility if you just want the shape that you describe is to use the perspective :

.shape {
  background: #41423D;
  width: 150px;
  height: 150px;
  margin: 20px auto;
  transform-origin:50% 100%;
  transform:perspective(100px) rotateX(30deg);
  box-shadow: 2px 2px 15px #41423D;
}

<div class="shape"></div>