Is it possible to style a div to be trapezoidal?

Question

I know it's possible to skew but I don't see a way to skew each corner with a particular degree.

Here's the project I'm working on: http://map.ucf.edu/

Looking specifically at the tabs within the menu. Right now I'm using images, I would like to change that for capable browsers.

I know it's possible to create a CSS trapazoid, but that is using borders without content. The end result also needs a bit of rounded corners.

edit: Starting with Zoltan Toth's solution I was able to achieve this: demo

div {
    height: 20px;
    padding:2px 5px 0 5px;
    color:white;
    background: rgba(0,0,0,.5);
    margin: 0 10px;
    position: relative;
    border-top-left-radius: 6px 4px;
    border-top-right-radius: 6px 4px;
    font-family:sans-serif;
    font-size:13px;
    line-height:20px;
    vertical-align:bottom;
    display:inline-block;
    white-space:nowrap;
}

div:before {
    content: '';
    line-height: 0;
    font-size: 0;
    width: 0;
    height: 0;
    border-bottom: 19px solid rgba(0,0,0,.5);
    border-left: 9px solid transparent;
    position: absolute;
    bottom: 0;
    left: -9px;
}

div:after {
    content: '';
    line-height: 0;
    font-size: 0;
    width: 0;
    height: 0;
    border-bottom: 19px solid rgba(0,0,0,.5);
    border-right: 9px solid transparent;
    position: absolute;
    bottom: 0;
    right: -9px;
}

.b { background:black; margin:0 -7px 0 20px; }
.b:after, .b:before { border-bottom-color:black; }

Answer 1

It is possible, here is the rough idea:

div {
    width: 200px;
    height: 100px;
    background: #ddd;
    margin: 20px 150px;
    position: relative
}

div:before {
    content: '';
    line-height: 0;
    font-size: 0;
    width: 0;
    height: 0;
    border-top: 50px solid transparent;
    border-bottom: 50px solid #ddd;
    border-left: 50px solid transparent;
    border-right: 50px solid #ddd;
    position: absolute;
    top: 0;
    left: -99px;
}

div:after {
    content: '';
    line-height: 0;
    font-size: 0;
    width: 0;
    height: 0;
    border-top: 50px solid transparent;
    border-bottom: 50px solid #ddd;
    border-left: 50px solid #ddd;
    border-right: 50px solid transparent;
    position: absolute;
    top: 0;
    right: -99px;
}

<div>Hello</div>

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Answer 2

We can use linear-gradient() to draw trapezoidal shape on rectangular element.

This trick uses the idea of dividing whole shape in different parts and then draws each shape on the background independently.

div {
  background-image:
   linear-gradient(to bottom right, transparent 50%, silver 50%), /* draws left part */
   linear-gradient(to bottom left, transparent 50%, silver 50%), /* draws right part */
   linear-gradient(to right, silver, silver); /* draws central flat part */

  background-repeat: no-repeat;

  /* Sets the background size of each of three shapes individually */
  background-size: 75px 100%, 75px 100%, calc(100% - 150px) 100%;

  /* Sets the background position of each of three shapes individually */
  background-position: 0 0, 100% 0, 75px 0;
}

body {
  background: linear-gradient(orange, red) no-repeat;
  min-height: 100vh;
  margin: 0;
}

div {
  background-image: linear-gradient(to bottom right, transparent 50%, silver 50%),
    linear-gradient(to bottom left, transparent 50%, silver 50%),
    linear-gradient(to right, silver, silver);

  background-size: 75px 100%, 75px 100%, calc(100% - 150px) 100%;
  background-position: 0 0, 100% 0, 75px 0;
  background-repeat: no-repeat;

  padding: 20px 80px;
  min-height: 80px;
  width: 300px;
  margin: 25px;
}

<div>
  Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... 
</div>

<div>
  Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... Lorem ipsum dolor sit amet... 
</div>