<div class="accordion">

  <!-- Panel 1 -->
  <div>
    <input type="checkbox" name="panel" id="panel-1">
    <label for="panel-1">Panel 1</label>
    <div class="accordion__content accordion__content--small">
      <h2 class="accordion__header">Header</h2>
      <p class="accordion__body">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Iusto possimus at a cum saepe molestias modi illo facere ducimus voluptatibus praesentium deleniti fugiat ab error quia sit perspiciatis velit necessitatibus.Lorem ipsum dolor sit amet, consectetur adipisicing elit. Lorem ipsum dolor sit amet.</p>
    </div>
  </div>

  <!-- Panel 2 -->
  <div>
    <input type="checkbox" name="panel" id="panel-2">
    <label for="panel-2">Panel 2</label>
    <div class="accordion__content accordion__content--med">
      <h2 class="accordion__header">Header</h2>
      <p class="accordion__body">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Iusto possimus at a cum saepe molestias modi illo facere ducimus voluptatibus praesentium deleniti fugiat ab error quia sit perspiciatis velit necessitatibus.Lorem ipsum dolor sit amet, consectetur adipisicing elit. Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sapiente eligendi nulla illo culpa ab in at adipisci eveniet id itaque maxime soluta recusandae doloribus laboriosam dignissimos est aut cupiditate delectus.</p>
    </div>
  </div>

  <!-- Panel 3 -->
  <div>
    <input type="checkbox" name="panel" id="panel-3">
    <label for="panel-3">Panel 3</label>
    <div class="accordion__content accordion__content--small">
      <h2 class="accordion__header">Header</h2>
      <p class="accordion__body">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Iusto possimus at a cum saepe molestias modi illo facere ducimus voluptatibus praesentium deleniti fugiat ab error quia sit perspiciatis velit necessitatibus.Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>
    </div>
  </div>

  <!-- Panel 4 -->
  <div>
    <input type="checkbox" name="panel" id="panel-4">
    <label for="panel-4">Panel 4</label>
    <div class="accordion__content accordion__content--large">
      <h2 class="accordion__header">Header</h2>
      <p class="accordion__body">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Iusto possimus at a cum saepe molestias modi illo facere ducimus voluptatibus praesentium deleniti fugiat ab error quia sit perspiciatis velit necessitatibus.Lorem ipsum dolor sit amet, consectetur adipisicing elit. Lorem ipsum dolor sit amet, consectetur adipisicing elit. Assumenda odio provident ullam culpa rem tempora voluptatem inventore facere adipisci doloribus dolorum ad maxime itaque quasi animi aliquid voluptates rerum expedita? Lorem ipsum dolor sit amet, consectetur adipisicing elit. Qui culpa amet neque nostrum cumque eaque corrupti ad accusantium? Consectetur reiciendis ad earum aspernatur at quibusdam cupiditate rerum ipsam consequatur suscipit. Lorem ipsum dolor sit amet, consectetur adipisicing elit. Ab rem explicabo exercitationem unde harum? Iste nobis quae animi illum laborum incidunt hic illo ad repellat repudiandae et alias facere magni.</p>
    </div>
  </div>

</div><!-- .accordion -->
/* 
* Typography
*/
@import url(https://fonts.googleapis.com/css?family=Open+Sans:400,700);


/*
* Color Variables
*/

$light-grey: #eee;
$med-grey: #666;
$dark-grey: #444;
$highlight-color: #1abc9c;


/*
* Animation Variables
*/

$timing: .4s;
$ease: cubic-bezier(0.865, 0.140, 0.095, 0.870);


/* 
* Global
*/

*,
*:before,
*:after {
  box-sizing: border-box;
}

/* 
* Base
*/

body {
  font-family: 'Open Sans', sans-serif;
  background: $light-grey;
  
  &:before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background: linear-gradient(to bottom, rgba(0,0,0,0) 0%,rgba(0,0,0,0.3) 100%);
  }
  
}


/*
* Accordion
*/

/* Basic Accordion Styles */
.accordion {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 75%;
  box-shadow: 0 1px 8px rgba(#000,.25);
  
  
  /* Radio Inputs */
  input[name='panel'] {
    display: none;
  }

  /* Labels */
  label {
    position: relative;
    display: block;
    padding: 1em;
    background: linear-gradient(to bottom, rgba(254,254,254,1) 0%,rgba(209,209,209,1) 50%,rgba(219,219,219,1) 55%,rgba(226,226,226,1) 100%);
    border-top: 1px solid #fff;
    border-bottom: 1px solid rgba(#000,.15);
    box-shadow: inset 0 2px 0 #fff;
    font-size: 1.5em;
    text-shadow: 0 1px 0 rgba(#fff,.75);
    color: $med-grey;
    cursor: pointer;
    transition: all $timing $ease;
    
    &:after {
      content: '+';
      position: absolute;
      right: 1em;
      width: 1em;
      height: 1em;
      color: $light-grey;
      text-align: center;
      border-radius: 50%;
      background: $highlight-color;
      box-shadow: inset 0 1px 6px rgba(#000,.5), 0 1px 0 #fff;
      text-shadow: 0 1px 0 rgba(#000,.75);     
    }
    
    &:hover {
      color: $highlight-color;
    }
      
  }
  
  input:checked + label {
    color: $highlight-color;
    
    &:after {
      content: '-';
      /* adjsut line-height to vertically center icon */
      line-height: .8em;
    }
    
  }
  
  /* Panel Content */
  .accordion__content {
    overflow: hidden;
    height: 0px;
    position: relative;
    padding: 0 1.5em;
    box-shadow: inset 4px 0 0 0 $highlight-color, inset 0 3px 6px rgba(#000,.75);
    background: $dark-grey;
    background: linear-gradient(to bottom, rgba(68,68,68,1) 0%,rgba(34,34,34,1) 100%);
    color: $light-grey;
    transition: height $timing $ease;
    
    &:not(:last-of-type) {
      box-shadow: inset 0 -2px 2px rgba(#000,.25), inset 4px 0 0 0 $highlight-color, inset 0 3px 6px rgba(#000,.75);
    }
    
    .accordion__header {
      padding: 1em 0;
    }
      
    .accordion__body {
      font-size: .825em;
      line-height: 1.4em;
    }
    
  }
   
}

/* 
* Size Variations
*/

input[name='panel']:checked ~ .accordion__content.accordion__content--small {
  height: 150px;
}

input[name='panel']:checked ~ .accordion__content.accordion__content--med {
  height: 200px;
}

input[name='panel']:checked ~ .accordion__content.accordion__content--large {
  height: 300px;
}
View Compiled

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js