* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: monospace, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  background-color: #000;
  color: #fff;
}

header {
  background-color: #333;
  padding: 20px;
}

footer {
  background-color: #333;
  padding: 20px;
  text-align: center;
  color: #fff;
}

main {
  padding: 20px;
}

article {
  border: 1px solid #666;
  padding: 20px;
  margin-bottom: 20px;
}

h1 {
  margin: 0;
  font-size: 2.5em;
}

h2 {
  margin-top: 0;
  margin-bottom: 4px;
}

h3 {
  margin-top: 0;
  margin-bottom: 1px;

}

/* hide by default */
main {
  display: none;
}

nav {
  position: fixed;
  text-align: right;
  padding-right: 5%;
  top: 0;
  width: 100%;
  z-index: 999;
}

nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

nav ul li {
  display: inline-block;
}

nav ul li a {
  display: block;
  padding: 5px;
  color: #fff;
  text-decoration: none;
}

nav ul li a:hover {
  background-color: #666;
}

button {
  color: #fff;
  background-color: #666;
  padding: 5px;
}

button:active {
  background-color: #333;
  color: #666;
}

button.inverted {
  background-color: #fff;
  color: #333;
}

/* maximize width but keep 16:9 aspect ratio */
.playerContainer {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  width: 100%;
}

.playerContainer iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}