/* Modern Clean UI Style - Layout B */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
  line-height: 1.6;
  color: #2c3e50;
  background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  min-height: 100vh;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

header {
  background: #fff;
  box-shadow: 0 2px 10px rgba(0,0,0,0.08);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 20px;
  max-width: 1200px;
  margin: 0 auto;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: #3498db;
  text-decoration: none;
  letter-spacing: 1px;
}

nav ul {
  display: flex;
  flex-wrap: nowrap;
  list-style: none;
  gap: 0;
  margin: 0;
  padding: 0;
  align-items: center;
}

nav ul li {
  flex: 1 1 0;
  min-width: 0;
}

nav ul li a {
  display: block;
  padding: 0.5rem 0.8rem;
  color: #34495e;
  text-decoration: none;
  transition: all 0.3s;
  font-weight: 500;
  text-align: center;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

nav ul li a:hover {
  color: #3498db;
  background: #ecf0f1;
}

main {
  padding: 2rem 0;
}

h1 {
  font-size: 2rem;
  color: #2c3e50;
  margin-bottom: 1.5rem;
  line-height: 1.3;
  font-weight: 700;
}

h2 {
  font-size: 1.5rem;
  color: #34495e;
  margin: 2rem 0 1rem;
  font-weight: 600;
  border-left: 4px solid #3498db;
  padding-left: 12px;
}

section {
  background: #fff;
  border-radius: 8px;
  padding: 2rem;
  margin-bottom: 2rem;
  box-shadow: 0 2px 15px rgba(0,0,0,0.06);
}

.intro-text {
  line-height: 1.8;
  color: #555;
  margin-bottom: 1.5rem;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.video-card {
  background: #fff;
  border: 1px solid #e1e8ed;
  border-radius: 8px;
  padding: 1.5rem;
  transition: all 0.3s;
  cursor: pointer;
}

.video-card:hover {
  box-shadow: 0 4px 20px rgba(52, 152, 219, 0.15);
  transform: translateY(-3px);
  border-color: #3498db;
}

.video-card h3 {
  font-size: 1.1rem;
  color: #2c3e50;
  margin-bottom: 0.8rem;
  font-weight: 600;
}

.video-card h3 a {
  color: inherit;
  text-decoration: none;
}

.video-card h3 a:hover {
  color: #3498db;
}

.video-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.8rem;
  font-size: 0.85rem;
}

.meta-tag {
  background: #ecf0f1;
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  color: #7f8c8d;
}

.video-desc {
  color: #666;
  font-size: 0.9rem;
  line-height: 1.6;
  margin-top: 0.8rem;
}

.video-list {
  list-style: none;
}

.video-list li {
  background: #f8f9fa;
  padding: 1.2rem;
  margin-bottom: 1rem;
  border-radius: 6px;
  border-left: 3px solid #3498db;
  transition: all 0.3s;
}

.video-list li:hover {
  background: #e9ecef;
  border-left-color: #2980b9;
}

.list-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1rem;
}

.list-links a {
  display: inline-block;
  padding: 0.6rem 1.2rem;
  background: #3498db;
  color: #fff;
  text-decoration: none;
  border-radius: 5px;
  transition: all 0.3s;
  font-weight: 500;
}

.list-links a:hover {
  background: #2980b9;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(52, 152, 219, 0.3);
}

.detail-info {
  background: #f8f9fa;
  padding: 1.5rem;
  border-radius: 6px;
  margin-bottom: 1.5rem;
}

.detail-info p {
  margin-bottom: 0.6rem;
  color: #555;
}

.detail-info strong {
  color: #2c3e50;
  display: inline-block;
  min-width: 70px;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

.tag {
  background: #3498db;
  color: #fff;
  padding: 0.3rem 0.8rem;
  border-radius: 20px;
  font-size: 0.85rem;
}

.review-box {
  background: #fff3cd;
  border-left: 4px solid #ffc107;
  padding: 1rem 1.5rem;
  margin: 1.5rem 0;
  border-radius: 4px;
}

.related-section {
  margin-top: 3rem;
}

footer {
  background: #34495e;
  color: #ecf0f1;
  text-align: center;
  padding: 2rem 0;
  margin-top: 3rem;
}

@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    gap: 0.8rem;
    padding: 0.8rem 15px;
  }

  .logo {
    font-size: 1.3rem;
  }

  nav ul {
    width: 100%;
    justify-content: space-between;
  }

  nav ul li a {
    padding: 0.4rem 0.3rem;
    font-size: 0.85rem;
  }

  h1 {
    font-size: 1.5rem;
  }

  h2 {
    font-size: 1.2rem;
  }

  section {
    padding: 1.2rem;
  }

  .video-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .container {
    padding: 0 15px;
  }
}

@media (max-width: 480px) {
  nav ul li a {
    padding: 0.4rem 0.2rem;
    font-size: 0.75rem;
  }
}