<div id="container" class="angled-top-left">
  <div class="content">
    <h1>Angled Edge</h1>
    <p>Here's the demo for applying the angled edges. Change the selections to apply the angled edge in the direction you want.</p>
    <select id="selectStyle" onchange="changeStyle()">
      <option value="angled-top-left">Angle Top Left</option>
      <option value="angled-top-right">Angle Top Right</option>
      <option value="angled-bottom-left">Angle Bottom Left</option>
      <option value="angled-bottom-right">Angle Bottom Right</option>
      <option value="angled-both-left">Angle Both Left</option>
      <option value="angled-both-right">Angle Both Right</option>
      <option value="angled-both-left-right">Angle Both Left Right</option>
      <option value="angled-both-right-left">Angle Both Right Left</option>
    </select> 
  </div>
</div>

$color1: #011627; //rgba(1, 22, 39, 100)
$color2: #fdfffc; //rgba(253, 255, 252, 100)
$color3: #2ec4b6; //rgba(46, 196, 182, 100)
$color4: #e71d36; //rgba(231, 29, 54, 100)
$color5: #ff9f1c; //rgba(255, 159, 28, 100)

body{
  margin: 0;
  font-family: 'Open Sans', sans-serif;
  font-size: 14px;
  color: #555;
}

#container{
  margin-top: 100px;
  height: 400px;
  width: 100%;
  position: relative;
}
.content{
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  background: rgba(#fff, 0.9);
  border-radius: 8px;
  width: 25%;
  padding: 40px;
  text-align: center;
  -webkit-box-shadow: 0 0 8px 0 rgba(0,0,0, 0.12);
  box-shadow: 0 0 8px 0 rgba(0,0,0, 0.12);
  h1{
    font-family: Georgia, serif;
    font-size: 40px;
    font-weight: normal;
  }
}
#selectStyle{
  margin-top: 20px;
}

@mixin angle-edge($pos-top:null, $angle-top:null, $pos-btm:null, $angle-btm:null){
  width: 100%;
  position: relative;
  background: linear-gradient(to right, rgba(241,231,103,1) 0%, rgba(254,182,69,1) 100%);
  &:before,
  &:after{
    content: '';
    width: 100%;
    height: 100%;
    position: absolute;
    background: inherit;
    z-index: -1;
    transition: ease all .5s;
  }

  @if $pos-top{
    &:before{
      @if $pos-top == 'topleft'{
        top: 0;
        transform-origin: right top;
        transform: skewY($angle-top);
      }
      @if $pos-top == 'topright' {
        top: 0;
        transform-origin: left top;
        transform: skewY(-$angle-top);
      } 
    }
  }

  @if $pos-btm{
    &:after{
      @if $pos-btm == 'bottomleft' {
        bottom: 0;
        transform-origin: right bottom;
        transform: skewY(-$angle-btm);
      } 

      @if $pos-btm == 'bottomright' {
        bottom: 0;
        transform-origin: left bottom;
        transform: skewY($angle-btm);
      } 
    }
  }


}

.angled-top-left{
  @include angle-edge($pos-top: topleft, $angle-top: 3deg);
}

.angled-top-right{
  @include angle-edge($pos-top: topright, $angle-top: 3deg);
}

.angled-bottom-left{
  @include angle-edge($pos-btm: bottomleft, $angle-btm: 3deg);
}

.angled-bottom-right{
  @include angle-edge($pos-btm: bottomright, $angle-btm: 3deg);
}

.angled-both-left{
  @include angle-edge(topleft, 3deg, bottomleft, 3deg);
}
.angled-both-right{
  @include angle-edge(topright, 3deg, bottomright, 3deg);
}
.angled-both-left-right{
  @include angle-edge(topleft, 3deg, bottomright, 3deg);
}
.angled-both-right-left{
  @include angle-edge(topright, 3deg, bottomleft, 3deg);
}

function changeStyle() {
  var x = document.getElementById("selectStyle").value;
  document.getElementById("container").className = "" + x;
}