.close {
  position: absolute;
  right: 16px;
  top: 16px;
  width: 32px;
  height: 32px;
  opacity: 0.7;
}
.close:hover {
  opacity: 1;
}
.close:before,
.close:after {
  position: absolute;
  left: 15px;
  content: ' ';
  height: 33px;
  width: 3px;
  background-color: #333;
}
.close:before {
  transform: rotate(45deg);
}
.close:after {
  transform: rotate(-45deg);
}
pre {
  white-space: pre-wrap;
}