.container {
  margin-top: 1em;
}
label {
  display: inline-block;
}
.viewport {
  display: inline-block;
  position: relative;
}
img, video, #note, #timing {
  display: none;
  max-width: 100%;
}
#videoBtn.button-primary ~ .viewport > #video,
#timing.visible {
  display: block;
}
#canvas {
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
}
pre {
  white-space: pre-wrap;
  word-wrap: break-word;
  margin-top: 0;
}