body {
  margin: 0;
  font-family: sans-serif;
  background-color: #111;
  color: #fff;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.container {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(3, 240px);
  grid-template-rows: repeat(3, 240px);
  gap: 10px;
}

.video-cell {
  background-color: #000;
  display: flex;
  justify-content: center;
  align-items: center;
}

.video-cell iframe {
  width: 100%;
  height: 100%;
}

.main-video {
  border: 2px solid deeppink;
}

.nav {
  background-color: #333;
  border: none;
  color: white;
  font-size: 2rem;
  padding: 10px 20px;
  cursor: pointer;
}

.nav:hover {
  background-color: #555;
}