/* ============================================
   AI SEO Lessons — Styles
   ============================================ */

:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: #1a1a26;
  --bg-card-hover: #22223a;
  --text-primary: #e8e8ed;
  --text-secondary: #9898a8;
  --text-muted: #6a6a7a;
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --accent-glow: rgba(99, 102, 241, 0.15);
  --border: #2a2a3a;
  --tag-bg: #1e1e2e;
  --tag-text: #a8a8c0;
  --success: #22c55e;
  --warning: #f59e0b;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
  --max-width: 1200px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* Header */
.site-header {
  padding: 24px 0;
  border-bottom: 1px solid var(--border);
  background: var(--bg-secondary);
}

.site-header .container {
  display: flex;
  align-items: center;
  gap: 24px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text-primary);
  font-size: 1.25rem;
  font-weight: 700;
}

.logo-icon { font-size: 1.5rem; }

.tagline {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* Hero */
.hero {
  text-align: center;
  padding: 64px 0 48px;
}

.hero h1 {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 16px;
  background: linear-gradient(135deg, var(--text-primary), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-sub {
  color: var(--text-secondary);
  font-size: 1.125rem;
  max-width: 500px;
  margin: 0 auto;
}

/* Niche Grid */
.niche-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 16px;
  padding-bottom: 64px;
}

.niche-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 24px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
  color: var(--text-primary);
}

.niche-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.niche-card .icon {
  font-size: 2.5rem;
  margin-bottom: 12px;
  display: block;
}

.niche-card .name {
  font-weight: 600;
  font-size: 1rem;
  margin-bottom: 4px;
}

.niche-card .count {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* View Management */
.view { display: none; }
.view.active { display: block; }

.view-header {
  padding: 32px 0 24px;
}

.view-header h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-top: 12px;
}

.view-header p {
  color: var(--text-secondary);
  margin-top: 4px;
}

.back-btn {
  background: none;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.875rem;
  transition: all 0.2s;
}

.back-btn:hover {
  border-color: var(--accent);
  color: var(--text-primary);
}

/* Filter Bar */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 24px;
}

.filter-tag {
  background: var(--tag-bg);
  color: var(--tag-text);
  border: 1px solid var(--border);
  padding: 6px 14px;
  border-radius: 20px;
  cursor: pointer;
  font-size: 0.8rem;
  transition: all 0.2s;
}

.filter-tag:hover,
.filter-tag.active {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}

/* Search */
.search-bar {
  margin-bottom: 24px;
}

.search-bar input {
  width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-primary);
  padding: 14px 20px;
  border-radius: var(--radius);
  font-size: 1rem;
  outline: none;
  transition: border-color 0.2s;
}

.search-bar input:focus {
  border-color: var(--accent);
}

.search-bar input::placeholder {
  color: var(--text-muted);
}

/* Lessons Grid */
.lessons-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 20px;
  padding-bottom: 48px;
}

.lesson-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  cursor: pointer;
  transition: all 0.2s ease;
}

.lesson-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.lesson-card .thumb {
  width: 100%;
  aspect-ratio: 16/9;
  background: linear-gradient(135deg, var(--bg-secondary), var(--bg-card-hover));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
  color: var(--text-muted);
}

.lesson-card .card-body {
  padding: 20px;
}

.lesson-card .card-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 12px;
  line-height: 1.4;
}

.lesson-card .card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 12px;
}

.lesson-card .card-tags span {
  background: var(--tag-bg);
  color: var(--tag-text);
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.lesson-card .card-takeaway {
  color: var(--text-secondary);
  font-size: 0.85rem;
  display: flex;
  align-items: start;
  gap: 8px;
}

.lesson-card .card-takeaway::before {
  content: '💡';
  flex-shrink: 0;
}

/* Lesson Detail */
.lesson-detail {
  max-width: 800px;
}

.video-wrapper {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  background: var(--bg-card);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 32px;
}

.video-wrapper iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

.lesson-detail h1 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.lesson-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 32px;
}

.lesson-meta .niche-tag {
  background: var(--accent-glow);
  color: var(--accent-hover);
  padding: 4px 12px;
  border-radius: 12px;
  font-size: 0.8rem;
  font-weight: 500;
}

.lesson-meta .topic-tag {
  background: var(--tag-bg);
  color: var(--tag-text);
  padding: 4px 12px;
  border-radius: 12px;
  font-size: 0.8rem;
}

.takeaways {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  margin-bottom: 48px;
}

.takeaways h3 {
  font-size: 1.125rem;
  margin-bottom: 16px;
}

.takeaways ul {
  list-style: none;
}

.takeaways li {
  padding: 8px 0;
  padding-left: 24px;
  position: relative;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.5;
}

.takeaways li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--success);
  font-weight: 700;
}

.related-section {
  padding-bottom: 64px;
}

.related-section h3 {
  font-size: 1.25rem;
  margin-bottom: 20px;
}

/* Empty State */
.empty-state {
  text-align: center;
  padding: 64px 0;
  color: var(--text-muted);
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 32px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.footer-credit {
  margin-top: 8px;
}

.footer-credit a {
  color: var(--accent-hover);
  text-decoration: none;
}

.footer-credit a:hover {
  text-decoration: underline;
}

/* Browse All Card */
.browse-all-card {
  background: var(--bg-card);
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 32px 24px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
  color: var(--text-secondary);
  grid-column: 1 / -1;
}

.browse-all-card:hover {
  border-color: var(--accent);
  color: var(--text-primary);
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 { font-size: 1.75rem; }
  .niche-grid { grid-template-columns: repeat(2, 1fr); }
  .lessons-grid { grid-template-columns: 1fr; }
  .site-header .container { flex-direction: column; gap: 8px; }
  .tagline { display: none; }
}

@media (max-width: 480px) {
  .niche-grid { grid-template-columns: 1fr; }
  .hero { padding: 40px 0 32px; }
}