body {
  font-family: sans-serif;
  background: #fdfdfd;
  color: #111;
  margin: 2rem;
}
.card {
  background: #fff;
  border: 1px solid #ddd;
  border-radius: 6px;
  padding: 1rem;
  margin-bottom: 1rem;
}
a {
  color: #0055cc;
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}
video, iframe {
  width: 100%;
  max-width: 640px;
  height: 360px;
  margin-top: 1rem;
}