html, body {
  width: 100%;
  height: 100%;
}

#container {
  width: 100%;
  height: 100%;
  flex-direction: column;
  display: flex;
}

#viewport {
  display: flex;
  flex-direction: row;
  flex-grow: 1;
  min-height: 0;
}

#nav {
  margin-top: 1.5em;
  width: 200px;
  max-height: 100%;
  overflow-y: scroll;  
  flex-shrink: 0;
  box-sizing: border-box;
  text-align: center;
}

#nav .arrow-down {
  width: 0; 
  height: 0; 
  border-left: 7px solid transparent;
  border-right: 7px solid transparent;
  border-top: 15px solid black;
  display: inline-block;
  margin: 1em 45% 0.5em;
  opacity: 0.6;
}

#nav .active {
  opacity: 1;
}

#nav div {
  opacity: 0.4;
}

#content {
  display: flex;
  flex-direction: column;
  flex-grow: 1;
  padding: 1em;
  max-width: calc( 100% - 210px );
  box-sizing: border-box;
  min-height: 0;
}

#commands {
  width: 100%;
  text-align: center;  
  flex-shrink: 0;
}

#commands a {
  margin: 1em 2%;
  width: 16%;
}
#commands a:last-child {
  text-align: center;
  width: 5em;
}

#content textarea,
#content .CodeMirror {
  flex: 1;
  resize: none;
  max-width: 100%;
  background-color: #fafafa;
}
#content .CodeMirror-gutters {
  background-color: #bdbdbd;
  
}
#content .CodeMirror-linenumber {
  color: #212121;
}