/* ==========================================================================
   小牛智连 (xiaoniuzl.cfd) - Dark Mode & Neon Glassmorphism Design System
   ========================================================================== */

:root {
  --bg-primary: #07090e;
  --bg-secondary: #0f172a;
  --bg-card: rgba(15, 23, 42, 0.65);
  --bg-card-hover: rgba(30, 41, 59, 0.8);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-glow: rgba(56, 189, 248, 0.3);
  
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  
  --accent-cyan: #00f2fe;
  --accent-blue: #38bdf8;
  --accent-purple: #8b5cf6;
  --accent-pink: #ec4899;
  --accent-gold: #f59e0b;

  --gradient-neon: linear-gradient(135deg, #00f2fe 0%, #4facfe 50%, #7928ca 100%);
  --gradient-gold: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
  --gradient-btn: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
  --gradient-glow: radial-gradient(circle at 50% -20%, rgba(56, 189, 248, 0.15), transparent 70%);

  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 9999px;

  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 25px rgba(56, 189, 248, 0.25);
  --shadow-purple-glow: 0 0 30px rgba(139, 92, 246, 0.3);

  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
  background-color: var(--bg-primary);
  color: var(--text-main);
  font-family: var(--font-family);
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
}

body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: var(--gradient-glow);
  pointer-events: none;
  z-index: 0;
}

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

a:hover {
  color: var(--accent-cyan);
}

.container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

/* Glassmorphism utility */
.glass-card {
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.glass-card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(255, 255, 255, 0.18);
  box-shadow: var(--shadow-glow);
}

/* Typography & Headings */
h1, h2, h3, h4 {
  color: var(--text-main);
  font-weight: 700;
  line-height: 1.25;
}

.gradient-text {
  background: var(--gradient-neon);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.3);
  border-radius: var(--radius-full);
  color: var(--accent-cyan);
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 16px;
  letter-spacing: 0.5px;
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 60px auto;
}

.section-header h2 {
  font-size: 2.5rem;
  margin-bottom: 16px;
}

.section-header p {
  color: var(--text-muted);
  font-size: 1.125rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 28px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  border: none;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: var(--gradient-btn);
  color: #ffffff;
  box-shadow: 0 4px 20px rgba(59, 130, 246, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(139, 92, 246, 0.6);
  color: #ffffff;
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-main);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.3);
  color: #ffffff;
}

.btn-accent {
  background: linear-gradient(135deg, #10b981 0%, #059669 100%);
  color: #ffffff;
  box-shadow: 0 4px 20px rgba(16, 185, 129, 0.3);
}

.btn-accent:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(16, 185, 129, 0.5);
  color: #ffffff;
}

/* Header & Navbar */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(7, 9, 14, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 16px 0;
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.35rem;
  font-weight: 800;
  color: #ffffff;
  letter-spacing: -0.5px;
}

.brand-logo svg {
  width: 42px;
  height: 42px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* Hero Section */
.hero {
  padding: 100px 0 80px 0;
  text-align: center;
  position: relative;
}

.hero h1 {
  font-size: 3.5rem;
  line-height: 1.15;
  margin-bottom: 24px;
  letter-spacing: -1px;
}

.hero p {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 800px;
  margin: 0 auto 40px auto;
}

.hero-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  margin-bottom: 50px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-top: 60px;
  padding: 30px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}

.stat-item {
  text-align: center;
}

.stat-number {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--accent-cyan);
  margin-bottom: 4px;
}

.stat-label {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Node Map Section */
.nodes-section {
  padding: 80px 0;
}

.node-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.node-card {
  padding: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.node-info {
  display: flex;
  align-items: center;
  gap: 16px;
}

.node-flag {
  font-size: 2rem;
  line-height: 1;
}

.node-name {
  font-weight: 700;
  font-size: 1.05rem;
}

.node-detail {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.node-ping {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.875rem;
  font-weight: 600;
  color: #10b981;
}

.ping-dot {
  width: 8px;
  height: 8px;
  background: #10b981;
  border-radius: 50%;
  box-shadow: 0 0 10px #10b981;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); opacity: 0.8; }
  50% { transform: scale(1.2); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.8; }
}

/* Features Section */
.features-section {
  padding: 80px 0;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  padding: 32px;
  position: relative;
  overflow: hidden;
}

.feature-icon {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  background: rgba(56, 189, 248, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  color: var(--accent-cyan);
}

.feature-icon svg {
  width: 28px;
  height: 28px;
}

.feature-card h3 {
  font-size: 1.35rem;
  margin-bottom: 12px;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Pricing Section */
.pricing-section {
  padding: 100px 0;
  background: radial-gradient(circle at 50% 50%, rgba(15, 23, 42, 0.8), var(--bg-primary));
}

.pricing-tabs {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-bottom: 48px;
}

.tab-btn {
  padding: 10px 24px;
  font-weight: 600;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition);
}

.tab-btn.active, .tab-btn:hover {
  background: var(--accent-blue);
  color: #ffffff;
  border-color: var(--accent-blue);
  box-shadow: 0 4px 15px rgba(56, 189, 248, 0.3);
}

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

.pricing-card {
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
}

.pricing-card.popular {
  border: 1px solid var(--accent-blue);
  box-shadow: var(--shadow-glow);
  transform: translateY(-8px);
}

.popular-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gradient-neon);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 800;
  text-transform: uppercase;
  padding: 4px 14px;
  border-radius: var(--radius-full);
  letter-spacing: 1px;
}

.plan-name {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.plan-price {
  font-size: 2.2rem;
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 4px;
}

.plan-cycle {
  font-size: 0.875rem;
  color: var(--text-dim);
  margin-bottom: 20px;
}

.plan-traffic {
  display: inline-block;
  padding: 6px 12px;
  background: rgba(56, 189, 248, 0.1);
  color: var(--accent-cyan);
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: 0.9rem;
  margin-bottom: 24px;
}

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

.plan-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.plan-features li svg {
  width: 18px;
  height: 18px;
  color: #10b981;
  flex-shrink: 0;
}

/* App Support / Tutorial Section */
.app-section {
  padding: 80px 0;
}

.app-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 16px;
}

.app-badge {
  padding: 20px 16px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.app-badge svg {
  width: 36px;
  height: 36px;
  color: var(--accent-cyan);
}

.app-badge span {
  font-weight: 600;
  font-size: 0.95rem;
}

/* Article Showcase */
.articles-section {
  padding: 100px 0;
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.article-card {
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.article-card h3 {
  font-size: 1.2rem;
  margin-bottom: 12px;
  line-height: 1.4;
}

.article-card p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 20px;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-dim);
  border-top: 1px solid var(--border-color);
  padding-top: 16px;
}

/* Testimonials */
.testimonials-section {
  padding: 80px 0;
}

.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.testimonial-card {
  padding: 32px;
}

.user-stars {
  color: var(--accent-gold);
  margin-bottom: 16px;
  letter-spacing: 2px;
}

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

.user-profile {
  display: flex;
  align-items: center;
  gap: 14px;
}

.user-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--gradient-btn);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: #ffffff;
}

.user-name {
  font-weight: 700;
  font-size: 0.95rem;
}

.user-role {
  font-size: 0.8rem;
  color: var(--text-dim);
}

/* FAQ Section */
.faq-section {
  padding: 100px 0;
}

.faq-list {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  padding: 20px 28px;
  cursor: pointer;
}

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 1.1rem;
  font-weight: 700;
}

.faq-icon {
  width: 24px;
  height: 24px;
  transition: transform 0.3s ease;
  color: var(--accent-cyan);
}

.faq-item.active .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, margin-top 0.3s ease;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 300px;
  margin-top: 16px;
}

/* Footer & PBN Injection Area */
footer {
  background: #040609;
  border-top: 1px solid var(--border-color);
  padding: 60px 0 40px 0;
  text-align: center;
  position: relative;
  z-index: 10;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
  margin-bottom: 40px;
}

.footer-nav {
  display: flex;
  gap: 24px;
  list-style: none;
  font-size: 0.9rem;
}

.footer-copyright {
  color: var(--text-dim);
  font-size: 0.875rem;
}

/* Low-profile Aesthetic PBN Links Zone */
.pbn-link-container {
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px dashed rgba(255, 255, 255, 0.06);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  font-size: 0.8rem;
  color: var(--text-dim);
}

.pbn-link-container a {
  color: rgba(148, 163, 184, 0.6);
  text-decoration: none;
  font-size: 0.8rem;
  transition: color 0.2s ease;
}

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

/* Responsive Media Queries */
@media (max-width: 1024px) {
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .features-grid, .articles-grid, .testimonials-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .app-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .hero h1 {
    font-size: 2.75rem;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }
  .hero-stats {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-grid, .features-grid, .articles-grid, .testimonials-grid {
    grid-template-columns: 1fr;
  }
  .app-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .hero h1 {
    font-size: 2.2rem;
  }
}