rt.css

.b-rt {
  font: normal 0px sans-serif;
  border: solid 1px #ddd;
}
.b-rt:before,
.b-rt:after {
  content: "";
  display: table;
}
.b-rt:after {
  clear: both;
}
.b-rt__heading {
  font-weight: bold;
  font-size: 14px;
  text-decoration: none;
  line-height: 25px;
  display: block;
  padding: 3px 7px;
  margin: 0 0 1px;
  color: #000;
  outline: none;
  background-color: #ddd;
  cursor: pointer;
}
.b-rt__heading:last-of-type {
  margin: 0;
}
.b-rt__heading:active,
.b-rt__heading:visited {
  color: #000;
}
.b-rt__heading:hover {
  background-color: #efefef;
  -webkit-transition: background-color 1s;
  -moz-transition: background-color 1s;
  transition: background-color 1s;
}
.b-rt__heading:target {
  color: #aaa;
  background-color: #fff;
}
.b-rt__heading:target + .b-rt__wrapper {
  position: static;
  display: block;
}
.b-rt__wrapper {
  font-size: 12px;
  position: absolute;
  display: none;
  padding: 3px 7px 10px;
}
@media (min-width: 768px) {
  .b-rt__heading {
    display: inline-block;
    margin: 0 1px 0 0;
  }
  .b-rt__heading:target + .b-rt__wrapper {
    display: block;
    float: right;
    display: -webkit-box;
    display: -webkit-flex;
  }
}