/* ============================================================
   Subject Landing Pages — SEO Lead Magnets
   Styles for /subjects/ index and individual subject pages.
   All colors/spacing via variables.css.
   ============================================================ */

/* --- Subject Hero --- */
.subject-hero {
  background: linear-gradient(135deg, var(--color-primary-700), var(--color-secondary));
  color: #fff;
  padding: 5rem 2rem 3rem;
  text-align: center;
}

.subject-hero .badge {
  display: inline-block;
  background: rgba(255,255,255,0.2);
  color: #fff;
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  padding: 0.35rem 1rem;
  border-radius: var(--radius-full);
  margin-bottom: 1rem;
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
}

.subject-hero h1 {
  font-size: var(--text-4xl);
  font-weight: var(--font-extrabold);
  line-height: var(--leading-tight);
  max-width: 700px;
  margin: 0 auto 1rem;
}

.subject-hero .subtitle {
  font-size: var(--text-lg);
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto;
  line-height: var(--leading-relaxed);
}

@media (max-width: 639px) {
  .subject-hero { padding: 3.5rem 1.25rem 2rem; }
  .subject-hero h1 { font-size: var(--text-2xl); }
  .subject-hero .subtitle { font-size: var(--text-base); }
}

/* --- Content Sections --- */
.subject-body {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.subject-section {
  padding: 3rem 0;
}

.subject-section h2 {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--color-neutral-900);
  margin-bottom: 1.5rem;
}

.subject-section p {
  font-size: var(--text-base);
  line-height: var(--leading-relaxed);
  color: var(--color-neutral-600);
  margin-bottom: 1rem;
}

/* --- Term Grid --- */
.term-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: var(--space-4);
  margin-top: var(--space-4);
}

.term-card {
  background: var(--color-neutral-0);
  border: 1px solid var(--color-neutral-200);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  transition: box-shadow var(--transition-fast);
}

.term-card:hover {
  box-shadow: var(--shadow-md);
}

.term-card h3 {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  color: var(--color-primary-700);
  margin-bottom: var(--space-2);
}

.term-card .term-meta {
  font-size: var(--text-sm);
  color: var(--color-neutral-400);
  margin-bottom: var(--space-3);
}

.term-card ul {
  list-style: disc;
  padding-left: 1.25rem;
}

.term-card li {
  font-size: var(--text-sm);
  color: var(--color-neutral-600);
  line-height: var(--leading-relaxed);
  margin-bottom: 0.25rem;
}

/* --- Features Strip --- */
.features-strip {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--space-4);
  margin-top: var(--space-4);
}

.feature-card {
  text-align: center;
  padding: var(--space-5);
  background: var(--color-neutral-50);
  border-radius: var(--radius-lg);
}

.feature-card .icon {
  font-size: 2rem;
  margin-bottom: var(--space-2);
}

.feature-card h3 {
  font-size: var(--text-base);
  font-weight: var(--font-semibold);
  color: var(--color-neutral-800);
  margin-bottom: var(--space-1);
}

.feature-card p {
  font-size: var(--text-sm);
  color: var(--color-neutral-500);
  margin: 0;
}

/* --- Sample Content Preview (blurred) --- */
.sample-preview {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--color-neutral-200);
  border-radius: var(--radius-lg);
  margin-top: var(--space-4);
}

.sample-content {
  padding: var(--space-6);
  filter: blur(4px);
  user-select: none;
  pointer-events: none;
}

.sample-content h4 {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  color: var(--color-neutral-800);
  margin-bottom: var(--space-3);
}

.sample-content p {
  font-size: var(--text-sm);
  color: var(--color-neutral-600);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-2);
}

.sample-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(255,255,255,0.7);
  text-align: center;
  padding: var(--space-6);
}

@media (prefers-color-scheme: dark) {
  .sample-overlay {
    background: rgba(15,23,42,0.75);
  }
}

.sample-overlay .lock-icon {
  font-size: 2.5rem;
  margin-bottom: var(--space-3);
}

.sample-overlay p {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  color: var(--color-neutral-800);
  margin-bottom: var(--space-4);
}

.sample-overlay .btn-primary {
  font-size: var(--text-base);
}

/* --- FAQ --- */
.faq-list {
  margin-top: var(--space-4);
}

.faq-item {
  border-bottom: 1px solid var(--color-neutral-200);
  padding: var(--space-4) 0;
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-question {
  font-weight: var(--font-semibold);
  color: var(--color-neutral-800);
  margin-bottom: var(--space-2);
}

.faq-answer {
  font-size: var(--text-sm);
  color: var(--color-neutral-600);
  line-height: var(--leading-relaxed);
}

/* --- Subject CTA Banner --- */
.subject-cta {
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  color: #fff;
  text-align: center;
  padding: 3.5rem 2rem;
  margin-top: var(--space-8);
  border-radius: var(--radius-xl);
}

.subject-cta h2 {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: #fff;
  margin-bottom: var(--space-3);
}

.subject-cta p {
  color: rgba(255,255,255,0.9);
  max-width: 500px;
  margin: 0 auto var(--space-5);
}

.subject-cta .btn-white {
  display: inline-block;
  background: #fff;
  color: var(--color-primary-700);
  font-weight: var(--font-bold);
  padding: 0.85rem 2.5rem;
  border-radius: var(--radius);
  text-decoration: none;
  font-size: var(--text-base);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.subject-cta .btn-white:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}

/* --- Breadcrumb --- */
.breadcrumb {
  max-width: 900px;
  margin: 0 auto;
  padding: var(--space-3) 1.5rem;
  font-size: var(--text-sm);
  color: var(--color-neutral-400);
}

.breadcrumb a {
  color: var(--color-neutral-400);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--color-primary);
}

.breadcrumb .sep {
  margin: 0 0.5rem;
}

/* --- Subjects Index Grid --- */
.subjects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-5);
  margin-top: var(--space-6);
}

.subject-card {
  background: var(--color-neutral-0);
  border: 1px solid var(--color-neutral-200);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  text-decoration: none;
  color: inherit;
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
  display: block;
}

.subject-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.subject-card .card-level {
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  text-transform: uppercase;
  letter-spacing: var(--tracking-wide);
  color: var(--color-primary);
  margin-bottom: var(--space-2);
}

.subject-card h3 {
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
  color: var(--color-neutral-800);
  margin-bottom: var(--space-2);
}

.subject-card p {
  font-size: var(--text-sm);
  color: var(--color-neutral-500);
  line-height: var(--leading-relaxed);
  margin-bottom: var(--space-3);
}

.subject-card .card-meta {
  font-size: var(--text-xs);
  color: var(--color-neutral-400);
}

/* --- Section Divider --- */
.subject-index-section h2 {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--color-neutral-900);
  padding-bottom: var(--space-3);
  border-bottom: 2px solid var(--color-primary-100);
  margin-bottom: var(--space-4);
}

/* --- Related Subjects --- */
.related-subjects {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-4);
}

.related-chip {
  display: inline-block;
  padding: 0.5rem 1rem;
  background: var(--color-neutral-50);
  border: 1px solid var(--color-neutral-200);
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
  color: var(--color-neutral-700);
  text-decoration: none;
  transition: background var(--transition-fast);
}

.related-chip:hover {
  background: var(--color-primary-50);
  color: var(--color-primary);
  border-color: var(--color-primary-200);
}