body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f8f9fa;
}

.sidebar {
  position: fixed;
  width: 250px;
  height: 100%;
  background: #ffffff;
  padding-top: 20px;
  border-right: 1px solid #dddddd;
}

.sidebar a {
  display: block;
  padding: 15px 20px;
  text-decoration: none;
  color: #333333;
}

.sidebar a.active {
  background: #f0f0f0;
  font-weight: bold;
}

.content {
  margin-left: 250px;
  padding: 20px;
  text-align: center;
}

.videos iframe {
  width: 80%;
  height: 400px;
  margin: 20px 0;
}