.panel-group {
  margin-bottom: 20px;
}
.panel-group .panel {
  margin-top: 10px;
  border-radius: 4px;
}
.panel-group .panel-heading {
  padding: 10px 15px;
}
.panel-group .panel-default {
  border: 1px solid #ddd;
}
.panel-group .panel-default > .panel-heading {
  color: #333;
  background-color: #f5f5f5;
}
.panel-group .panel-body {
  padding: 15px;
}
.fade {
  opacity: 0;
  -webkit-transition: opacity 0.15s linear;
  -o-transition: opacity 0.15s linear;
  transition: opacity 0.15s linear;
  display: none;
  visibility: hidden;
}
.fade.in,
.fade.active {
  opacity: 1;
  display: block;
  visibility: visible;
}
.collapse {
  display: none;
}
.collapse.in {
  display: block;
}
.collapsing {
  position: relative;
  height: 0;
  overflow: hidden;
  -webkit-transition-timing-function: ease;
  -o-transition-timing-function: ease;
  transition-timing-function: ease;
  -webkit-transition-duration: .35s;
  -o-transition-duration: .35s;
  transition-duration: .35s;
  -webkit-transition-property: height, visibility;
  -o-transition-property: height, visibility;
  transition-property: height, visibility;
}