* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
  background: #f4f4f4;
  color: #111;
  padding: 20px;
}

header {
  background: #1e1e2f;
  color: #fff;
  text-align: center;
  padding: 30px 15px;
  border-radius: 12px;
}

header h1 {
  font-size: 1.8rem;
}

.ad-banner {
  display: inline-block;
  margin-top: 15px;
  padding: 12px 20px;
  background: #ff4d4f;
  color: white;
  text-decoration: none;
  font-weight: bold;
  border-radius: 8px;
}

.ad-banner:hover {
  background-color: #e60000;
}

.video-section {
  margin: 30px auto;
  max-width: 720px;
}

main {
  max-width: 900px;
  margin: auto;
  padding: 20px;
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 0 15px rgba(0,0,0,0.1);
}

h2, h3 {
  color: #333;
  margin-top: 20px;
}

ul, ol {
  margin-left: 20px;
}

footer {
  text-align: center;
  padding: 20px;
  margin-top: 30px;
  font-size: 0.9rem;
  color: #666;
}