/* === Reset & Base === */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  color: #1F2937;
  background: #FFFFFF;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
}

a {
  color: #7C3AED;
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: #6D28D9;
}

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

/* === Typography === */
h1, h2, h3, h4 {
  line-height: 1.2;
  font-weight: 700;
}

h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  letter-spacing: -0.01em;
}

h3 {
  font-size: 1.25rem;
}

p {
  color: #4B5563;
  margin-bottom: 1rem;
}

/* === Navigation === */
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid #E5E7EB;
}

nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1.125rem;
  font-weight: 700;
  color: #1F2937;
}

.nav-logo img {
  height: 36px;
  width: auto;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: #4B5563;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: #7C3AED;
}

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.mobile-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: #1F2937;
  margin: 5px 0;
  transition: 0.3s;
}

/* === Hero Section === */
.hero {
  padding: 140px 0 80px;
  background: linear-gradient(135deg, #F5F3FF 0%, #FFF7ED 100%);
  text-align: center;
}

.hero h1 {
  margin-bottom: 20px;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.hero h1 span {
  background: linear-gradient(135deg, #7C3AED, #F97316);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.125rem;
  max-width: 640px;
  margin: 0 auto 32px;
  color: #6B7280;
}

.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: 12px;
  font-size: 0.9375rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
  text-decoration: none;
}

.btn-primary {
  background: #7C3AED;
  color: #FFFFFF;
}

.btn-primary:hover {
  background: #6D28D9;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(124, 58, 237, 0.3);
}

.btn-secondary {
  background: #FFFFFF;
  color: #1F2937;
  border: 1px solid #E5E7EB;
}

.btn-secondary:hover {
  background: #F9FAFB;
  border-color: #D1D5DB;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 48px;
  margin-top: 56px;
  flex-wrap: wrap;
}

.stat {
  text-align: center;
}

.stat-value {
  font-size: 1.75rem;
  font-weight: 800;
  color: #7C3AED;
}

.stat-label {
  font-size: 0.8125rem;
  color: #6B7280;
  margin-top: 4px;
}

/* === Section common === */
.section {
  padding: 80px 0;
}

.section-dark {
  background: #F9FAFB;
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-header h2 {
  margin-bottom: 12px;
}

.section-header p {
  max-width: 560px;
  margin: 0 auto;
  color: #6B7280;
}

/* === How It Works (numbered steps) === */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}

.step-card {
  background: #FFFFFF;
  border: 1px solid #E5E7EB;
  border-radius: 16px;
  padding: 32px 24px;
  position: relative;
  transition: box-shadow 0.2s;
}

.step-card:hover {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}

.step-number {
  font-size: 2.5rem;
  font-weight: 800;
  color: #7C3AED;
  opacity: 0.2;
  line-height: 1;
  margin-bottom: 12px;
}

.step-card h3 {
  margin-bottom: 8px;
}

.step-card p {
  font-size: 0.9375rem;
  color: #6B7280;
  margin-bottom: 0;
}

/* === Featured Content Grid === */
.content-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
}

.content-card {
  background: #FFFFFF;
  border: 1px solid #E5E7EB;
  border-radius: 16px;
  overflow: hidden;
  transition: box-shadow 0.2s, transform 0.2s;
}

.content-card:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
  transform: translateY(-2px);
}

.content-card-body {
  padding: 24px;
}

.content-card .category {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #7C3AED;
  margin-bottom: 8px;
}

.content-card h3 {
  font-size: 1.125rem;
  margin-bottom: 8px;
}

.content-card h3 a {
  color: #1F2937;
}

.content-card h3 a:hover {
  color: #7C3AED;
}

.content-card p {
  font-size: 0.875rem;
  color: #6B7280;
  margin-bottom: 0;
}

.content-card .read-more {
  display: inline-block;
  margin-top: 12px;
  font-size: 0.875rem;
  font-weight: 500;
  color: #7C3AED;
}

/* === Why Section === */
.why-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}

.why-card {
  padding: 24px;
  border-radius: 12px;
  background: #FFFFFF;
  border: 1px solid #E5E7EB;
}

.why-card .icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  font-size: 1.25rem;
  font-weight: 700;
  color: #7C3AED;
  background: #F5F3FF;
}

.why-card h3 {
  margin-bottom: 8px;
  font-size: 1.0625rem;
}

.why-card p {
  font-size: 0.875rem;
  color: #6B7280;
  margin-bottom: 0;
}

/* === FAQ === */
.faq-list {
  max-width: 720px;
  margin: 0 auto;
}

.faq-item {
  border: 1px solid #E5E7EB;
  border-radius: 12px;
  margin-bottom: 12px;
  overflow: hidden;
}

.faq-question {
  width: 100%;
  padding: 18px 24px;
  background: none;
  border: none;
  text-align: left;
  font-size: 1rem;
  font-weight: 600;
  color: #1F2937;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 0.2s;
}

.faq-question:hover {
  background: #F9FAFB;
}

.faq-question::after {
  content: '+';
  font-size: 1.25rem;
  color: #9CA3AF;
  transition: transform 0.2s;
}

.faq-item.active .faq-question::after {
  content: '−';
}

.faq-answer {
  padding: 0 24px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq-item.active .faq-answer {
  padding: 0 24px 18px;
  max-height: 300px;
}

.faq-answer p {
  font-size: 0.9375rem;
  color: #6B7280;
  margin-bottom: 0;
}

/* === Deep Dive Section === */
.deep-dive {
  background: #1F2937;
  color: #FFFFFF;
  padding: 80px 0;
}

.deep-dive h2 {
  color: #FFFFFF;
}

.deep-dive p {
  color: #9CA3AF;
}

.deep-dive-card {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 16px;
  padding: 32px;
  margin-bottom: 20px;
}

.deep-dive-card h3 {
  color: #FFFFFF;
  margin-bottom: 8px;
}

.deep-dive-card p {
  color: #9CA3AF;
  font-size: 0.9375rem;
  margin-bottom: 16px;
}

.deep-dive-card .btn {
  background: #7C3AED;
  color: #FFFFFF;
}

.deep-dive-card .btn:hover {
  background: #6D28D9;
}

/* === Sources / Primary Sources === */
.sources-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.source-card {
  border: 1px solid #E5E7EB;
  border-radius: 12px;
  padding: 20px 24px;
  transition: box-shadow 0.2s;
}

.source-card:hover {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
}

.source-card h4 {
  font-size: 1rem;
  margin-bottom: 6px;
}

.source-card p {
  font-size: 0.8125rem;
  color: #6B7280;
  margin-bottom: 0;
}

.source-card a {
  font-size: 0.875rem;
  font-weight: 500;
}

/* === Footer === */
footer {
  background: #1F2937;
  color: #FFFFFF;
  padding: 48px 0 32px;
}

footer .container {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 32px;
}

.footer-col h4 {
  font-size: 0.875rem;
  font-weight: 600;
  color: #FFFFFF;
  margin-bottom: 16px;
}

.footer-col ul {
  list-style: none;
}

.footer-col li {
  margin-bottom: 8px;
}

.footer-col a {
  font-size: 0.875rem;
  color: #9CA3AF;
}

.footer-col a:hover {
  color: #FFFFFF;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  font-size: 0.8125rem;
  color: #6B7280;
  flex-wrap: wrap;
  gap: 12px;
}

/* === Responsive === */
@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: #FFFFFF;
    flex-direction: column;
    padding: 16px 24px;
    border-bottom: 1px solid #E5E7EB;
    gap: 16px;
  }

  .nav-links.open {
    display: flex;
  }

  .mobile-toggle {
    display: block;
  }

  .hero {
    padding: 100px 0 60px;
  }

  .hero-stats {
    gap: 24px;
  }

  .section {
    padding: 48px 0;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}

/* === Page Header (for subpages) === */
.page-header {
  padding: 120px 0 48px;
  background: #F5F3FF;
}

.page-header h1 {
  margin-bottom: 8px;
}

.page-header p {
  color: #6B7280;
  max-width: 640px;
}

/* === Contact Form === */
.contact-form {
  max-width: 560px;
  margin: 0 auto;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 6px;
  color: #1F2937;
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid #E5E7EB;
  border-radius: 10px;
  font-size: 0.9375rem;
  font-family: inherit;
  transition: border-color 0.2s;
  background: #FFFFFF;
  color: #1F2937;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: #7C3AED;
  box-shadow: 0 0 0 3px rgba(124, 58, 237, 0.1);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

/* === CTA Banner === */
.cta-banner {
  background: linear-gradient(135deg, #7C3AED, #F97316);
  padding: 64px 0;
  text-align: center;
}

.cta-banner h2 {
  color: #FFFFFF;
  margin-bottom: 12px;
}

.cta-banner p {
  color: rgba(255, 255, 255, 0.85);
  max-width: 560px;
  margin: 0 auto 24px;
}

.cta-banner .btn {
  background: #FFFFFF;
  color: #7C3AED;
}

.cta-banner .btn:hover {
  background: #F5F3FF;
  transform: translateY(-1px);
}

/* === Content categories === */
.category-tag {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 8px;
}

.category-tag.ai-photo {
  background: #F5F3FF;
  color: #7C3AED;
}

.category-tag.ai-video {
  background: #FFF7ED;
  color: #F97316;
}

.category-tag.capcut {
  background: #ECFDF5;
  color: #059669;
}

.category-tag.vn-code {
  background: #E0F2FE;
  color: #0284C7;
}