body {
  background-color: #eee;
  margin: 0;
  padding: 0; }

h1 {
  /*font-size: 2em;*/
  font-size: 3em;
  margin-top: 0.67em;
  margin-bottom: 0.67em; }

h2 {
  /*font-size: 1.5em;*/
  font-size: 2.3em;
  margin-top: 0.83em;
  margin-bottom: 0.83em; }

h3 {
  /*font-size: 1.17em;*/
  font-size: 1.5em;
  margin-top: 1em;
  margin-bottom: 1em; }

p {
  /*font-size: 1em;*/
  font-size: 0.9em;
  margin-top: 1em;
  margin-bottom: 1em; }

a {
  color: #159f9f; }

section {
  margin-bottom: 60px; }

section:last-child {
  margin-bottom: calc(100vh - 5 00px); }

.warning {
  background-color: #ffcece;
  color: #ff5656;
  border: 2px solid #ff5656;
  padding: 15px; }

.container {
  width: 800px;
  margin: auto;
  padding: 45px 0px; }

.content {
  width: 100%;
  height: 300vh;
  padding-left: 230px;
  box-sizing: border-box;
  color: #333; }

.hljs {
  padding: 15px 10px;
  border: 2px solid #ccc; }

.syntax {
  font-weight: bold;
  display: block;
  margin-bottom: 10px;
  font-size: 1.1em; }

.example-code {
  color: #159f9f;
  font-size: 0.9em;
  text-decoration: underline;
  cursor: pointer; }

.popup {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -1;
  transition: all 0.4s; }
  .popup-content {
    position: absolute;
    top: 50%;
    left: 50%;
    background-color: #fff;
    transition: all 0.4s;
    transform: translate(-50%, 100vh);
    box-shadow: 0 10px 16px 0 rgba(0, 0, 0, 0.2); }
  .popup.active {
    z-index: 1;
    background-color: rgba(0, 0, 0, 0.5); }
    .popup.active .popup-content {
      transform: translate(-50%, -50%); }

.stage {
  width: 1060px;
  height: 410px;
  padding: 10px;
  box-sizing: border-box; }
  .stage .CodeMirror, .stage iframe {
    display: inline-block;
    border: 1px solid #eee;
    box-sizing: border-box;
    width: 517px;
    height: 390px; }

.treemenu {
  position: fixed;
  width: 230px;
  height: 100vh;
  box-sizing: border-box; }
  .treemenu a {
    border-left: 3px solid transparent;
    padding: 2px 7px;
    color: #777;
    text-decoration: none; }
  .treemenu li {
    padding-top: 7px; }
    .treemenu li > a {
      font-size: 0.9em; }
    .treemenu li li > a {
      font-size: 0.8em; }
  .treemenu ul {
    list-style-type: none;
    padding-left: 15px; }
    .treemenu ul ul {
      display: none; }
  .treemenu li.focus ul {
    display: list-item; }
  .treemenu li.focus > a {
    color: #159f9f;
    border-left: 3px solid #159f9f; }

.btns {
  position: absolute;
  bottom: -60px;
  left: 50%;
  transform: translateX(-50%); }

.btn {
  display: inline-block;
  border: 0;
  margin: 3px;
  font-size: 1.4em;
  color: white;
  box-shadow: 0 10px 16px 0 rgba(0, 0, 0, 0.2);
  border-radius: 3px;
  padding: 5px 15px; }
  .btn.start {
    background-color: #d13b21; }
  .btn.start:hover {
    background-color: #e8553c; }