/* ==========================================================================
   悦通 (yueto.cfd) - Global Glassmorphism & Cyber Dark Theme Styling
   Theme D: High-Contrast Dark Gradient Glassmorphism (深色夜空与高饱和玻璃拟态)
   ========================================================================== */

:root {
  --bg-dark: #0b0f19;
  --bg-card: rgba(255, 255, 255, 0.04);
  --bg-card-hover: rgba(255, 255, 255, 0.08);
  --border-color: rgba(255, 255, 255, 0.1);
  --border-glow: rgba(99, 102, 241, 0.4);
  
  --primary-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #d946ef 100%);
  --accent-cyan: #06b6d4;
  --accent-green: #10b981;
  --accent-orange: #f59e0b;
  
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  
  --glass-blur: blur(16px);
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-pill: 9999px;
  
  --shadow-glow: 0 10px 30px -10px rgba(99, 102, 241, 0.5);
  --shadow-card: 0 20px 40px rgba(0, 0, 0, 0.4);
  --transition-fast: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Reset & Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

html {
  scroll-behavior: smooth;
  background-color: var(--bg-dark);
  color: var(--text-main);
  line-height: 1.6;
}

body {
  background: radial-gradient(circle at 15% 15%, rgba(99, 102, 241, 0.15) 0%, transparent 40%),
              radial-gradient(circle at 85% 75%, rgba(6, 182, 212, 0.12) 0%, transparent 40%),
              var(--bg-dark);
  min-height: 100vh;
  overflow-x: hidden;
}

a {
  color: var(--accent-cyan);
  text-decoration: none;
  transition: var(--transition-fast);
}

a:hover {
  color: #38bdf8;
}

/* Container */
.container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Header & Navigation */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(11, 15, 25, 0.75);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-bottom: 1px solid var(--border-color);
}

.nav-wrapper {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 80px;
}

.logo-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.logo-img {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  object-fit: cover;
  box-shadow: 0 0 15px rgba(99, 102, 241, 0.4);
}

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

.nav-link {
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition-fast);
}

.nav-link:hover {
  color: var(--text-main);
}

/* Glass Buttons Base */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 28px;
  border-radius: var(--radius-pill);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: var(--transition-fast);
  text-align: center;
  border: 1px solid transparent;
  white-space: nowrap;
}

.btn-primary {
  background: var(--primary-gradient);
  color: #fff;
  box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 15px 35px -5px rgba(99, 102, 241, 0.7);
  color: #fff;
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-main);
  border: 1px solid var(--border-color);
  backdrop-filter: var(--glass-blur);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.3);
  color: var(--text-main);
  transform: translateY(-2px);
}

/* Hero Section */
.hero {
  padding: 100px 0 60px;
  text-align: center;
  position: relative;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  border-radius: var(--radius-pill);
  background: rgba(99, 102, 241, 0.12);
  border: 1px solid rgba(99, 102, 241, 0.3);
  color: var(--accent-cyan);
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 24px;
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -1px;
}

.gradient-text {
  background: linear-gradient(135deg, #38bdf8 0%, #8b5cf6 50%, #ec4899 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 780px;
  margin: 0 auto 40px;
}

/* Hero 3 Buttons Alignment & Mobile Responsiveness */
.hero-cta-group {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  max-width: 900px;
  margin: 0 auto 50px;
}

.hero-cta-group .btn {
  flex: 1 1 auto;
  min-width: 220px;
  max-width: 280px;
}

/* Section Title Styling */
.section-title {
  text-align: center;
  margin-bottom: 50px;
}

.section-title h2 {
  font-size: 2.4rem;
  font-weight: 800;
  margin-bottom: 12px;
}

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

/* Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 28px;
  margin-bottom: 80px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  backdrop-filter: var(--glass-blur);
  padding: 32px;
  border-radius: var(--radius-md);
  transition: var(--transition-fast);
}

.feature-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-glow);
  transform: translateY(-5px);
  box-shadow: var(--shadow-card);
}

.feature-icon {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  background: rgba(99, 102, 241, 0.15);
  color: var(--accent-cyan);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 20px;
}

.feature-card h3 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 12px;
}

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

/* Pricing Section - 4 Even Plans */
.pricing-section {
  padding: 60px 0 100px;
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-top: 40px;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  backdrop-filter: var(--glass-blur);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition-fast);
}

.pricing-card.popular {
  border-color: #8b5cf6;
  background: rgba(139, 92, 246, 0.08);
  box-shadow: 0 0 30px rgba(139, 92, 246, 0.25);
  transform: scale(1.03);
}

.pricing-card:hover {
  transform: translateY(-6px);
  border-color: var(--accent-cyan);
}

.badge-popular {
  position: absolute;
  top: -14px;
  right: 24px;
  background: var(--primary-gradient);
  color: #fff;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 4px 14px;
  border-radius: var(--radius-pill);
  text-transform: uppercase;
}

.plan-name {
  font-size: 1.4rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.plan-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 24px;
  min-height: 40px;
}

.plan-price {
  font-size: 2.8rem;
  font-weight: 900;
  color: var(--text-main);
  margin-bottom: 24px;
  display: flex;
  align-items: baseline;
}

.plan-price span {
  font-size: 1rem;
  color: var(--text-muted);
  font-weight: 400;
  margin-left: 4px;
}

.plan-features {
  list-style: none;
  margin-bottom: 32px;
  flex-grow: 1;
}

.plan-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.plan-features li i {
  color: var(--accent-green);
}

/* App Download Badges */
.app-support-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 20px;
  margin: 40px 0 80px;
}

.app-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  backdrop-filter: var(--glass-blur);
  padding: 24px;
  border-radius: var(--radius-md);
  text-align: center;
  transition: var(--transition-fast);
}

.app-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent-cyan);
}

.app-card h4 {
  font-size: 1.1rem;
  margin-top: 10px;
}

.app-card span {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Article Index Grid */
.articles-section {
  padding: 60px 0 100px;
  background: rgba(255, 255, 255, 0.015);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 28px;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  backdrop-filter: var(--glass-blur);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition-fast);
}

.article-card:hover {
  transform: translateY(-5px);
  border-color: var(--accent-cyan);
  box-shadow: var(--shadow-card);
}

.article-meta {
  font-size: 0.85rem;
  color: var(--accent-cyan);
  font-weight: 600;
  margin-bottom: 10px;
}

.article-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 12px;
}

.article-card p {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.article-link {
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

/* Testimonial Section */
.testimonial-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
  margin-bottom: 80px;
}

.testimonial-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  backdrop-filter: var(--glass-blur);
  border-radius: var(--radius-md);
  padding: 28px;
}

.stars {
  color: var(--accent-orange);
  margin-bottom: 14px;
  font-size: 1rem;
}

.testimonial-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 20px;
  font-style: italic;
}

.user-info {
  display: flex;
  align-items: center;
  gap: 12px;
}

.avatar-placeholder {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--primary-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: #fff;
}

/* FAQ Accordion Section */
.faq-section {
  max-width: 860px;
  margin: 0 auto 100px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  backdrop-filter: var(--glass-blur);
  border-radius: var(--radius-md);
  margin-bottom: 16px;
  overflow: hidden;
}

.faq-question {
  padding: 22px 28px;
  font-size: 1.1rem;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
}

.faq-question::after {
  content: '+';
  font-size: 1.5rem;
  color: var(--accent-cyan);
  transition: transform 0.3s;
}

.faq-item.active .faq-question::after {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s cubic-bezier(0, 1, 0, 1);
  padding: 0 28px;
  color: var(--text-muted);
  font-size: 0.98rem;
}

.faq-item.active .faq-answer {
  max-height: 500px;
  padding: 0 28px 24px;
  transition: max-height 0.3s ease-in-out;
}

/* Footer & PBN Links Section */
footer {
  background: rgba(7, 10, 18, 0.95);
  border-top: 1px solid var(--border-color);
  padding: 50px 0 30px;
  text-align: center;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.3rem;
  font-weight: 800;
}

.footer-brand img {
  width: 32px;
  height: 32px;
  border-radius: 6px;
}

.footer-copyright {
  color: var(--text-dim);
  font-size: 0.9rem;
}

/* PBN Friendly Links Section (精细、高融合度、低调) */
.pbn-links-wrapper {
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px dashed rgba(255, 255, 255, 0.08);
  width: 100%;
  max-width: 600px;
}

.pbn-links-title {
  font-size: 0.8rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 10px;
}

.pbn-links-grid {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}

.pbn-link {
  font-size: 0.88rem;
  color: var(--text-muted);
  transition: var(--transition-fast);
  text-decoration: none;
}

.pbn-link:hover {
  color: var(--accent-cyan);
  text-decoration: underline;
}

/* Responsive Rules for Mobile */
@media (max-width: 1024px) {
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-card.popular {
    transform: none;
  }
}

@media (max-width: 768px) {
  .hero-title {
    font-size: 2.2rem;
  }
  .hero-subtitle {
    font-size: 1rem;
  }
  .hero-cta-group {
    flex-direction: column;
    width: 100%;
  }
  .hero-cta-group .btn {
    width: 100%;
    max-width: 100%;
  }
  .pricing-grid {
    grid-template-columns: 1fr;
  }
  .nav-links {
    display: none; /* simple mobile hide or scroll */
  }
  .articles-grid {
    grid-template-columns: 1fr;
  }
}