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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  color: #333;
  background: #f5f5f5;
}

body.ui-style-14 {
  --primary-color: hsl(315, 65%, 55%);
  --secondary-color: hsl(495, 60%, 50%);
  --accent-color: hsl(405, 70%, 60%);
}

a {
  color: var(--primary-color, #2c5282);
  text-decoration: none;
  transition: color 0.3s;
}

a:hover {
  color: var(--accent-color, #3182ce);
}

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

header {
  background: linear-gradient(135deg, var(--primary-color, #2d3748) 0%, var(--secondary-color, #1a202c) 100%);
  color: white;
  padding: 1.5rem 0;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.logo {
  font-size: 1.8rem;
  font-weight: bold;
  color: white;
}

nav {
  display: flex;
  gap: 0.5rem;
  flex-wrap: nowrap;
  align-items: center;
}

nav a {
  color: white;
  padding: 0.6rem 1rem;
  border-radius: 4px;
  transition: all 0.3s;
  white-space: nowrap;
  font-size: 0.95rem;
}

nav a:hover {
  background: rgba(255,255,255,0.2);
  transform: translateY(-2px);
}

@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    align-items: stretch;
  }

  nav {
    display: flex;
    flex-wrap: nowrap;
    justify-content: space-between;
    align-items: center;
    overflow: hidden;
  }

  nav a {
    flex: 1 1 0;
    min-width: 0;
    text-align: center;
    padding: 0.5rem 0.3rem;
    font-size: 0.85rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }
}

main {
  padding: 2rem 0;
  min-height: 60vh;
}

h1 {
  font-size: 2rem;
  margin-bottom: 1rem;
  color: #1a202c;
  line-height: 1.3;
}

h2 {
  font-size: 1.5rem;
  margin: 2rem 0 1rem;
  color: #2d3748;
  border-left: 4px solid var(--primary-color, #3182ce);
  padding-left: 1rem;
}

section {
  background: white;
  padding: 2rem;
  margin-bottom: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.intro-text {
  font-size: 1.05rem;
  line-height: 1.8;
  color: #4a5568;
  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: white;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  transition: all 0.3s;
  border: 1px solid #e2e8f0;
}

.video-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 16px rgba(0,0,0,0.15);
}

.video-card-content {
  padding: 1.2rem;
}

.video-title {
  font-size: 1.1rem;
  font-weight: bold;
  margin-bottom: 0.5rem;
  color: #1a202c;
}

.video-meta {
  display: flex;
  gap: 1rem;
  margin: 0.5rem 0;
  font-size: 0.9rem;
  color: #718096;
  flex-wrap: wrap;
}

.video-oneline {
  font-size: 0.95rem;
  color: #4a5568;
  margin: 0.8rem 0;
  line-height: 1.6;
}

.video-tags {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-top: 0.8rem;
}

.tag {
  background: #edf2f7;
  padding: 0.25rem 0.6rem;
  border-radius: 4px;
  font-size: 0.85rem;
  color: #4a5568;
}

.detail-info {
  background: #f7fafc;
  padding: 1.5rem;
  border-radius: 8px;
  margin: 1.5rem 0;
}

.info-row {
  display: flex;
  margin-bottom: 0.8rem;
  line-height: 1.8;
}

.info-label {
  font-weight: bold;
  min-width: 80px;
  color: #2d3748;
}

.info-value {
  color: #4a5568;
}

.summary-text {
  font-size: 1.05rem;
  line-height: 1.9;
  color: #2d3748;
  margin: 1.5rem 0;
  text-align: justify;
}

.review-box {
  background: #fff5e6;
  border-left: 4px solid #f59e0b;
  padding: 1.2rem;
  margin: 1.5rem 0;
  border-radius: 4px;
}

.review-text {
  font-size: 1rem;
  line-height: 1.8;
  color: #78350f;
  font-style: italic;
}

.list-item {
  background: white;
  padding: 1.5rem;
  margin-bottom: 1.2rem;
  border-radius: 8px;
  border: 1px solid #e2e8f0;
  transition: all 0.3s;
}

.list-item:hover {
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
  border-color: var(--primary-color, #3182ce);
}

.list-item-title {
  font-size: 1.2rem;
  font-weight: bold;
  margin-bottom: 0.8rem;
  color: #1a202c;
}

footer {
  background: #2d3748;
  color: white;
  padding: 2rem 0;
  text-align: center;
  margin-top: 3rem;
}

.back-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--primary-color, #3182ce);
  color: white;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  display: none;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  transition: all 0.3s;
}

.back-top:hover {
  background: var(--accent-color, #2c5282);
  transform: translateY(-3px);
}

.ranking-number {
  display: inline-block;
  width: 30px;
  height: 30px;
  line-height: 30px;
  text-align: center;
  background: var(--primary-color, #3182ce);
  color: white;
  border-radius: 50%;
  font-weight: bold;
  margin-right: 0.8rem;
}

.topic-group {
  margin-bottom: 2rem;
  padding: 1rem;
  background: #f7fafc;
  border-radius: 8px;
}

.topic-title {
  font-size: 1.2rem;
  font-weight: bold;
  color: #2d3748;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid #e2e8f0;
}

@media (max-width: 768px) {
  h1 {
    font-size: 1.5rem;
  }

  h2 {
    font-size: 1.2rem;
  }

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

  section {
    padding: 1.5rem;
  }
}