/* Necessary for functionality */

.folding-content,
.unfolded-content {
  display: none;
}

.unfolded-content {
  width: 100%;
}

.unfolded-content .folding-content {
  display: block;
}

.menu-item:hover,
.close-unfolded-content:hover {
  cursor: pointer;
}

/* Stuff to make the demo look nice */

html {
  box-sizing: border-box;
  height: 100%;
}

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

body {
  font-family: verdana, sans-serif;
  margin: 0;
  height: 100%;
}

#menu-container a {
  text-decoration: none;
  color: #3498DB;
}

#menu-container {
  width: 100%;
  min-height: 100%;
  background: #222;
  border: 20px solid #fff;
}

.folding-menu {
  /* remove inline-block extra spacing */
  font-size: 0;
  padding: 0;
}

.folding-menu li {
  list-style-type: none;
}

.menu-item {
  text-align: center;
  display: inline-block;
  padding: 50px;
  margin: 20px;
  background: #e0e0e0;
  transition: background 0.3s;
  font-size: 15px;
  vertical-align: top;
}

.menu-item:hover {
  background: #e6e6e6;
}

.menu-item:after {
  content: '';
  border-top: 0 solid #e6e6e6;
}

.unfolded-content {
  font-size: 15px;
  background: #ddd;
  padding: 20px;
  box-sizing: border-box;
  position: relative;
}

.active-item {
  background: #ccc;
  position: relative;
}

.active-item:after {
  content: '';
  width: 0;
  height: 0;
  position: absolute;
  left: calc( 50% - 40px );
  bottom: -40px;
  border-top: 40px solid #ccc;
  border-right: 40px solid transparent;
  border-bottom: 00px solid transparent;
  border-left: 40px solid transparent;
  z-index: 10;
  transition: border-top-color 0.3s;
}

.active-item:hover:after {
  border-top: 40px solid #e6e6e6;
}

.close-unfolded-content {
  position: absolute;
  top: 20px;
  right: 20px;
  height: 20px;
  width: 20px;
  text-align: center;
  background: #fff;
  transition: color 0.3s, background 0.3s;
}

.close-unfolded-content:hover {
  color: #fff;
  background: #444;
}