body {
  background-color: black;
  color: white
}

video {
  padding: 10px;
}

p {
  padding: 5px;
}

a:link {
  color: CornflowerBlue;
}

a:visited {
  color: Azure;
}

li {
  padding: 5px;
}

.wrapper {
  width: 1300px;
  margin: auto;
}

.headerbox {
  border: 0px outset white;
  margin: 0 auto;
  justify-content: center;
  align-content: center;
  display: grid;
}

.headerbox .header {
  border: 2px inset white;
  border-bottom: 2px none;
  margin: 0 auto;
  margin-bottom: 10px;
  display: inline-grid;
  align-content: center;
}

.viewbox {
  border: 2px inset white;
  margin: 0 auto;
  min-height: 300px;
  display: -webkit-flex; /* Safari */
  display: flex; /* Standard syntax */
}

.viewbox .contentbox {
  border: 2px inset white;
  -webkit-flex: 1; /* Safari */
  -ms-flex: 1; /* IE 10 */
  flex: 1; /* Standard syntax */
  padding: 5px;
}

.viewbox .sectionbox {
  border: 2px inset white;
  max-width: 450px;
  overflow: hidden;
  -webkit-flex: 1; /* Safari */
  -ms-flex: 1; /* IE 10 */
  flex: 1; /* Standard syntax */
}

.video-nav {
  width: 50%;
  float: none;
  margin: auto;
  border: 2px outset white;
  border-top: 2px none;
}

.viewbox .contentbox pre code {
  background-color: #2b2b2b;
  border: 1px solid #999;
  display: block;
  padding: 10px;
}

.center {
  display: block;
  padding-left: 10px;
  padding-right: 10px;
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}