:root {
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --accent-color: #f59e0b;
  --text-main: #1f2937;
  --text-muted: #4b5563;
  --bg-main: #ffffff;
  --bg-alt: #f8fafc;
  --bg-card: #ffffff;
  --border-color: #e2e8f0;
  --border-focus: #3b82f6;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --max-width: 1200px;
  --header-height: 72px;
}

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

html {
  scroll-behavior: smooth;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--text-main);
  background-color: var(--bg-main);
  line-height: 1.6;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 1rem;
  background: var(--primary-color);
  color: #ffffff;
  padding: 0.5rem 1rem;
  z-index: 9999;
  border-radius: var(--radius-sm);
  text-decoration: none;
  font-weight: 600;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 1rem;
}

a {
  color: var(--primary-color);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 3px solid var(--border-focus);
  outline-offset: 2px;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header & Nav */
header.site-header {
  position: sticky;
  top: 0;
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  height: var(--header-height);
  display: flex;
  align-items: center;
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-main);
  text-decoration: none;
}

.logo-icon {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
  border-radius: var(--radius-sm);
}

nav.main-nav ul {
  display: flex;
  list-style: none;
  gap: 1.75rem;
  align-items: center;
}

nav.main-nav a {
  color: var(--text-main);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.5rem 0.25rem;
  transition: color 0.2s ease;
}

nav.main-nav a:hover {
  color: var(--primary-color);
  text-decoration: none;
}

.nav-cta {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.35rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  min-height: 44px;
  min-width: 44px;
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: center;
  text-decoration: none;
}

.btn-primary {
  background-color: var(--primary-color);
  color: #ffffff;
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  text-decoration: none;
}

.btn-secondary {
  background-color: var(--primary-light);
  color: var(--primary-color);
  border-color: #bfdbfe;
}

.btn-secondary:hover {
  background-color: #dbeafe;
  text-decoration: none;
}

.btn-lg {
  padding: 0.85rem 2rem;
  font-size: 1.1rem;
  border-radius: var(--radius-md);
}

/* Sections */
section {
  padding: 5rem 0;
  scroll-margin-top: calc(var(--header-height) + 1rem);
}

section.bg-alt {
  background-color: var(--bg-alt);
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 3.5rem;
}

.section-header h2 {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 1rem;
}

.section-header p {
  font-size: 1.1rem;
  color: var(--text-muted);
}

/* Hero Section */
.hero {
  position: relative;
  padding: 5.5rem 0 4.5rem;
  background-color: #f8fafc;
  background-image: 
    linear-gradient(180deg, rgba(255, 255, 255, 0.88) 0%, rgba(255, 255, 255, 0.93) 60%, rgba(255, 255, 255, 1) 100%),
    url('assets/hero-bg.jpg');
  background-size: cover;
  background-position: center center;
  background-repeat: no-repeat;
  text-align: center;
}

.knowledge-hero {
  position: relative;
  padding: 4.5rem 2rem 3.5rem;
  background-color: #f8fafc;
  background-image: 
    linear-gradient(180deg, rgba(255, 255, 255, 0.88) 0%, rgba(255, 255, 255, 0.93) 60%, rgba(255, 255, 255, 1) 100%),
    url('assets/hero-bg.jpg');
  background-size: cover;
  background-position: center center;
  background-repeat: no-repeat;
  text-align: center;
  border-radius: var(--radius-lg);
  margin: 1.5rem 0 2.5rem;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.hero-content {
  max-width: 860px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-block;
  background-color: #dbeafe;
  color: #1e40af;
  font-size: 0.875rem;
  font-weight: 600;
  padding: 0.35rem 1rem;
  border-radius: 9999px;
  margin-bottom: 1.5rem;
}

.hero h1 {
  font-size: 2.85rem;
  line-height: 1.25;
  font-weight: 900;
  margin-bottom: 1.25rem;
  color: #0f172a;
}

.hero .subtitle {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--primary-color);
  margin-bottom: 1rem;
}

.hero .intro {
  font-size: 1.1rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 2.25rem;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 2rem;
}

.hero-features-list {
  display: flex;
  justify-content: center;
  gap: 2rem;
  list-style: none;
  font-size: 0.95rem;
  color: var(--text-muted);
  font-weight: 500;
  flex-wrap: wrap;
}

.hero-features-list li::before {
  content: "✓ ";
  color: #10b981;
  font-weight: 800;
}

/* Feature Cards */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2.25rem 1.75rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.feature-icon-wrapper {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background-color: var(--primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
}

.feature-icon {
  width: 28px;
  height: 28px;
  fill: var(--primary-color);
}

.feature-card h3 {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 0.85rem;
  color: #0f172a;
}

.feature-card p {
  color: var(--text-muted);
  line-height: 1.65;
  font-size: 0.98rem;
}

/* Streaming & AI Cards */
.stream-ai-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.stream-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2.5rem 2rem;
  box-shadow: var(--shadow-sm);
}

.stream-card h3 {
  font-size: 1.45rem;
  margin-bottom: 0.75rem;
  color: #0f172a;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.stream-card p {
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.tags-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
}

.tag-badge {
  background: #f1f5f9;
  color: #334155;
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 600;
  border: 1px solid #e2e8f0;
}

/* Pricing Table */
.pricing-wrapper {
  overflow-x: auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-md);
  background: #ffffff;
}

.pricing-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  min-width: 650px;
}

.pricing-table caption {
  caption-side: bottom;
  text-align: right;
  padding: 0.75rem 1rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.pricing-table th,
.pricing-table td {
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.pricing-table th {
  background: #f8fafc;
  font-weight: 700;
  font-size: 1rem;
  color: #0f172a;
}

.pricing-table tr:last-child td {
  border-bottom: none;
}

.pricing-table tr:hover {
  background-color: #f8fafc;
}

.plan-name {
  font-size: 1.15rem;
  font-weight: 800;
  color: #0f172a;
  display: block;
}

.plan-badge {
  display: inline-block;
  background-color: #fef3c7;
  color: #92400e;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  margin-top: 0.25rem;
}

.plan-price {
  font-size: 1.5rem;
  font-weight: 900;
  color: var(--primary-color);
}

.plan-price span {
  font-size: 0.85rem;
  font-weight: 400;
  color: var(--text-muted);
}

/* Reviews Grid */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.75rem;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.review-stars {
  color: var(--accent-color);
  font-size: 1.1rem;
  margin-bottom: 0.75rem;
}

.review-text {
  font-size: 0.95rem;
  color: #334155;
  line-height: 1.6;
  margin-bottom: 1.25rem;
  font-style: italic;
}

.review-user {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.user-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: #e2e8f0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: #475569;
}

.user-meta strong {
  display: block;
  font-size: 0.9rem;
  color: #0f172a;
}

.user-meta span {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* FAQ Details */
.faq-list {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

details.faq-item {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  transition: border-color 0.2s ease;
}

details.faq-item[open] {
  border-color: #cbd5e1;
  background-color: #ffffff;
}

details.faq-item summary {
  font-size: 1.1rem;
  font-weight: 700;
  color: #0f172a;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
}

details.faq-item summary::-webkit-details-marker {
  display: none;
}

details.faq-item summary::after {
  content: "+";
  font-size: 1.4rem;
  font-weight: 400;
  color: var(--text-muted);
  transition: transform 0.2s ease;
}

details.faq-item[open] summary::after {
  content: "−";
}

details.faq-item .faq-answer {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid #f1f5f9;
  color: var(--text-muted);
  font-size: 0.98rem;
  line-height: 1.7;
}

/* Call to Action Banner */
.cta-banner {
  background: linear-gradient(135deg, #1e3a8a 0%, #2563eb 100%);
  color: #ffffff;
  padding: 4.5rem 0;
  text-align: center;
  border-radius: var(--radius-lg);
  margin-bottom: 5rem;
}

.cta-banner h2 {
  font-size: 2.25rem;
  font-weight: 900;
  margin-bottom: 1rem;
}

.cta-banner p {
  font-size: 1.15rem;
  opacity: 0.9;
  max-width: 680px;
  margin: 0 auto 2rem;
}

.btn-white {
  background-color: #ffffff;
  color: #1e3a8a;
  font-weight: 700;
}

.btn-white:hover {
  background-color: #f8fafc;
  text-decoration: none;
}

/* Footer */
footer.site-footer {
  background-color: #0f172a;
  color: #cbd5e1;
  padding: 3rem 0;
  margin-top: auto;
  border-top: 1px solid #1e293b;
}

.footer-nav {
  display: flex;
  justify-content: center;
  gap: 2.5rem;
  margin-bottom: 1.75rem;
  flex-wrap: wrap;
}

.footer-nav a {
  color: #cbd5e1;
  font-size: 0.95rem;
  font-weight: 500;
}

.footer-nav a:hover {
  color: #ffffff;
  text-decoration: underline;
}

.footer-copy {
  text-align: center;
  font-size: 0.85rem;
  color: #64748b;
}

/* Article & Content Layout */
.content-wrapper {
  max-width: 860px;
  margin: 2rem auto 4rem;
  padding: 0 1.5rem;
}

.article-header {
  margin-bottom: 2.5rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1.5rem;
}

.article-header h1 {
  font-size: 2.25rem;
  line-height: 1.35;
  font-weight: 800;
  color: #0f172a;
  margin-bottom: 1rem;
}

.article-meta {
  display: flex;
  gap: 1.25rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.article-body {
  font-size: 1.05rem;
  line-height: 1.8;
  color: #334155;
}

.article-body h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: #0f172a;
  margin: 2.5rem 0 1rem;
  scroll-margin-top: calc(var(--header-height) + 1rem);
}

.article-body h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: #1e293b;
  margin: 1.75rem 0 0.75rem;
}

.article-body p {
  margin-bottom: 1.25rem;
}

.article-body ul,
.article-body ol {
  margin: 1rem 0 1.5rem 1.5rem;
}

.article-body li {
  margin-bottom: 0.5rem;
}

.article-body blockquote {
  border-left: 4px solid var(--primary-color);
  padding: 0.75rem 1.25rem;
  background-color: var(--primary-light);
  margin: 1.5rem 0;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

/* Knowledge Cards Grid */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  margin-top: 2.5rem;
}

.article-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.article-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.article-card h2 {
  font-size: 1.15rem;
  line-height: 1.45;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: #0f172a;
}

.article-card p {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 1.25rem;
}

/* Responsive Media Queries */
@media (max-width: 1024px) {
  .features-grid,
  .articles-grid,
  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  header.site-header {
    height: auto;
    padding: 1rem 0;
  }
  
  .nav-container {
    flex-direction: column;
    gap: 1rem;
  }

  nav.main-nav ul {
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .features-grid,
  .stream-ai-grid,
  .articles-grid,
  .reviews-grid {
    grid-template-columns: 1fr;
  }

  .pricing-table th,
  .pricing-table td {
    padding: 1rem 0.75rem;
  }

  .btn {
    width: 100%;
  }

  .hero-actions {
    flex-direction: column;
    width: 100%;
  }
}

@media (max-width: 390px) {
  .container {
    padding: 0 1rem;
  }

  .hero h1 {
    font-size: 1.75rem;
  }
  
  .section-header h2 {
    font-size: 1.65rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}