body {
  font-family: 'Segoe UI', sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f9fdfc;
  color: #333;
  line-height: 1.6;
}

header, section, footer {
  padding: 20px;
  margin: 20px auto;
  max-width: 800px;
  background-color: #ffffff;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.08);
  border-radius: 8px;
}

h1, h2, h3, h4 {
  color: #2a7e7e;
  margin-bottom: 10px;
}

a {
  color: #0066cc;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}
.video-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}
@media (min-width: 600px) {
  .video-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}
iframe {
  width: 100%;
  height: 315px;
  border: none;
  border-radius: 5px;
}