style.css

* {
  margin: 0;
  padding: 0;
  font-family: Helvetica, Arial, sans-serif;
}

video, canvas {
  margin-left: 230px;
  margin-top: 120px;
  position: absolute;
}

header {
  position: absolute;
  width: 100%;
  background: #2e2f33;
  z-index: 2;
  padding: .7em 0;
}

header a {
  color: #fff;
  border-bottom: 1px dotted #a64ceb;
  text-decoration: none;
}

header p {
  color: #fff;
  text-align: center;
  font-size: 15px;
}

.demo-frame {
  width: 854px;
  height: 658px;
  position: fixed;
  top: 50%;
  left: 50%;
  margin: -329px 0 0 -429px;
  padding: 95px 20px 45px 34px;
  overflow: hidden;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  -ms-box-sizing: border-box;
  box-sizing: border-box;
}

.demo-container {
  width: 100%;
  height: 530px;
  position: relative;
  overflow: hidden;
}