/**
 * Topics Page Styles
 */

/* ==================== Page Header ==================== */
.topics-page {
  max-width: var(--nav-width);
  margin: 0 auto;
  padding: calc(var(--gap) * 2) var(--gap);
}

.page-header {
  text-align: center;
  margin-bottom: calc(var(--gap) * 4);
}

.page-header-content {
  max-width: 700px;
  margin: 0 auto;
}

.page-title {
  font-size: var(--text-5xl);
  font-weight: var(--font-bold);
  line-height: var(--leading-tight);
  margin: var(--gap) 0 calc(var(--gap) * 1.5);
  color: var(--primary);
}

.page-description {
  font-size: var(--text-lg);
  line-height: var(--leading-relaxed);
  color: var(--secondary);
  margin: 0 0 calc(var(--gap) * 2);
}

.page-stats {
  display: flex;
  justify-content: center;
  gap: calc(var(--gap) * 3);
  margin-top: calc(var(--gap) * 2);
}

.stat {
  text-align: center;
}

.stat-value {
  display: block;
  font-size: var(--text-3xl);
  font-weight: var(--font-bold);
  color: var(--accent);
  line-height: 1;
}

.stat-label {
  display: block;
  margin-top: 6px;
  font-size: var(--text-sm);
  color: #999;
  text-transform: uppercase;
  letter-spacing: var(--tracking-wide);
}

/* ==================== Topics Grid ==================== */
.topics-grid-section {
  margin-bottom: calc(var(--gap) * 4);
}

.topics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: calc(var(--gap) * 1.5);
}

.topic-card {
  position: relative;
  display: flex;
  align-items: center;
  gap: 16px;
  text-decoration: none;
  overflow: hidden;
}

.topic-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--gradient-primary);
  opacity: 0;
  transition: opacity 0.3s ease;
  z-index: 0;
}

.topic-card:hover::before {
  opacity: 0.05;
}

.topic-card > * {
  position: relative;
  z-index: 1;
}

.topic-icon {
  flex-shrink: 0;
  width: 56px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--gradient-primary);
  border-radius: var(--radius-md);
  color: white;
  transition: all 0.3s ease;
}

.topic-icon svg {
  width: 28px;
  height: 28px;
}

.topic-card:hover .topic-icon {
  transform: scale(1.1) rotate(5deg);
  box-shadow: var(--shadow-lg);
}

.topic-content {
  flex: 1;
  min-width: 0;
}

.topic-name {
  font-size: var(--text-xl);
  font-weight: var(--font-semibold);
  color: var(--primary);
  margin: 0 0 4px;
  line-height: 1.3;
}

.topic-count {
  font-size: var(--text-sm);
  color: #999;
  margin: 0;
}

.topic-link {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--code-bg);
  color: var(--accent);
  border-radius: 50%;
  transition: all 0.3s ease;
}

.topic-link svg {
  transition: transform 0.3s ease;
}

.topic-card:hover .topic-link {
  background: var(--accent);
  color: white;
}

.topic-card:hover .topic-link svg {
  transform: translateX(4px);
}

/* ==================== Empty State ==================== */
.empty-state {
  text-align: center;
  padding: calc(var(--gap) * 4);
}

.empty-state svg {
  color: var(--tertiary);
  margin-bottom: var(--gap);
}

.empty-state h3 {
  font-size: var(--text-2xl);
  font-weight: var(--font-semibold);
  color: var(--primary);
  margin: var(--gap) 0;
}

.empty-state p {
  font-size: var(--text-base);
  color: var(--secondary);
  margin: 0;
}

/* ==================== Related Section ==================== */
.related-section {
  margin-top: calc(var(--gap) * 4);
}

.section-header {
  text-align: center;
  margin-bottom: calc(var(--gap) * 2);
}

.section-title {
  font-size: var(--text-3xl);
  font-weight: var(--font-bold);
  color: var(--primary);
  margin: 0;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: calc(var(--gap) * 1.5);
  max-width: 800px;
  margin: 0 auto;
}

.related-card {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: calc(var(--gap) * 1.5);
  text-decoration: none;
}

.related-icon {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--code-bg);
  color: var(--accent);
  border-radius: var(--radius-md);
  transition: all 0.3s ease;
}

.related-icon svg {
  width: 24px;
  height: 24px;
}

.related-card:hover .related-icon {
  background: var(--accent);
  color: white;
  transform: scale(1.1);
}

.related-content {
  flex: 1;
}

.related-content h3 {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  color: var(--primary);
  margin: 0 0 4px;
}

.related-content p {
  font-size: var(--text-sm);
  color: var(--secondary);
  margin: 0;
}

/* ==================== Responsive Design ==================== */
@media (max-width: 1024px) {
  .topics-grid {
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  }
}

@media (max-width: 768px) {
  .topics-page {
    padding: var(--gap) 16px;
  }

  .page-title {
    font-size: var(--text-3xl);
  }

  .page-description {
    font-size: var(--text-base);
  }

  .page-stats {
    gap: calc(var(--gap) * 2);
  }

  .stat-value {
    font-size: var(--text-2xl);
  }

  .topics-grid {
    grid-template-columns: 1fr;
    gap: var(--gap);
  }

  .topic-card {
    padding: var(--gap);
  }

  .topic-icon {
    width: 48px;
    height: 48px;
  }

  .topic-icon svg {
    width: 24px;
    height: 24px;
  }

  .topic-name {
    font-size: var(--text-lg);
  }

  .section-title {
    font-size: var(--text-2xl);
  }

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

@media (max-width: 480px) {
  .page-title {
    font-size: var(--text-2xl);
  }

  .page-stats {
    flex-direction: column;
    gap: var(--gap);
  }

  .stat-value {
    font-size: var(--text-xl);
  }

  .topic-link {
    width: 36px;
    height: 36px;
  }

  .related-card {
    padding: var(--gap);
  }

  .related-icon {
    width: 40px;
    height: 40px;
  }

  .related-icon svg {
    width: 20px;
    height: 20px;
  }
}