div.sample-code {
  position: relative;
}
div.sample-code textarea {
  border: 1px solid #000;
  height: 10em;
  resize: vertical;
  font-family: "Ubuntu Mono", "Andale Mono", monospace;
}
div.sample-code textarea.code-editor {
  box-sizing: border-box;
  width: 70%;
}
div.sample-code textarea.code-output {
  float: right;
  box-sizing: border-box;
  width: 29%;
}
div.sample-code .run-button {
  position: absolute;
  top: 5px;
  right: 5px;
  opacity: 0.5;
  transition-duration: 0.3s;
}
div.sample-code .run-button:hover {
  opacity: 1;
}
.theme-dark div.sample-code textarea {
  background-color: #203040;
  color: #dec;
  border-color: #798;
}