/* 吹雪云 (chuixuecloud.xyz) Global Stylesheet */
:root {
  --bg-primary: #09090b;
  --bg-secondary: #121217;
  --bg-tertiary: #181820;
  --bg-card: rgba(24, 24, 32, 0.7);
  --bg-card-hover: rgba(32, 32, 45, 0.9);
  
  --border-color: rgba(168, 85, 247, 0.15);
  --border-glow: rgba(168, 85, 247, 0.4);
  
  --accent-purple: #a855f7;
  --accent-purple-glow: rgba(168, 85, 247, 0.35);
  --accent-purple-dark: #7e22ce;
  --accent-cyan: #06b6d4;
  --accent-green: #22c55e;
  
  --text-main: #f4f4f5;
  --text-muted: #a1a1aa;
  --text-dim: #71717a;
  
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --container-max: 1240px;
}

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

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

body {
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
  background: 
    radial-gradient(circle at 50% 0%, rgba(168, 85, 247, 0.12) 0%, transparent 60%),
    radial-gradient(circle at 100% 100%, rgba(6, 182, 212, 0.05) 0%, transparent 50%),
    var(--bg-primary);
}

/* Background Cyber Grid Pattern */
.grid-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 0;
  background-image: 
    linear-gradient(rgba(168, 85, 247, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(168, 85, 247, 0.04) 1px, transparent 1px);
  background-size: 40px 40px;
  mask-image: radial-gradient(ellipse at center, rgba(0, 0, 0, 0.8) 0%, transparent 80%);
}

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

/* Typography & Headings */
h1, h2, h3, h4 {
  color: #ffffff;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.25;
}

.text-gradient {
  background: linear-gradient(135deg, #ffffff 0%, var(--accent-purple) 60%, var(--accent-cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  background: rgba(168, 85, 247, 0.1);
  border: 1px solid var(--border-color);
  color: var(--accent-purple);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: 16px;
}

.section-title {
  font-size: 2.25rem;
  margin-bottom: 16px;
  text-align: center;
}

.section-desc {
  color: var(--text-muted);
  font-size: 1.05rem;
  text-align: center;
  max-width: 680px;
  margin: 0 auto 48px auto;
}

/* Header & Navigation */
header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: rgba(9, 9, 11, 0.8);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  transition: var(--transition);
}

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

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: #fff;
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.01em;
}

.brand-logo {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  object-fit: cover;
  box-shadow: 0 0 15px var(--accent-purple-glow);
}

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

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: var(--transition);
}

.nav-links a:hover {
  color: var(--accent-purple);
}

.header-cta {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 26px;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  outline: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-purple) 0%, var(--accent-purple-dark) 100%);
  color: #ffffff;
  box-shadow: 0 4px 20px var(--accent-purple-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 28px rgba(168, 85, 247, 0.5);
  background: linear-gradient(135deg, #c084fc 0%, var(--accent-purple) 100%);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-main);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--accent-purple);
  color: #fff;
}

.btn-outline {
  background: transparent;
  color: var(--accent-purple);
  border: 1px solid var(--border-color);
}

.btn-outline:hover {
  background: rgba(168, 85, 247, 0.1);
  border-color: var(--accent-purple);
}

/* Hero Section (Centered) */
.hero {
  padding-top: 150px;
  padding-bottom: 80px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 18px;
  background: rgba(168, 85, 247, 0.1);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  font-size: 0.88rem;
  color: var(--accent-purple);
  margin-bottom: 24px;
}

.hero-title {
  font-size: 3.4rem;
  font-weight: 800;
  line-height: 1.18;
  margin-bottom: 24px;
}

.hero-sub {
  font-size: 1.15rem;
  color: var(--text-muted);
  line-height: 1.7;
}

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

.hero-stats {
  display: flex;
  justify-content: space-around;
  gap: 32px;
  padding-top: 32px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.stat-item h4 {
  font-size: 2rem;
  color: var(--accent-purple);
}

.stat-item p {
  font-size: 0.88rem;
  color: var(--text-dim);
}

/* Hero Centered Radar Graphic Box */
.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.radar-box {
  width: 100%;
  max-width: 580px;
  height: 380px;
  border: 1px solid rgba(168, 85, 247, 0.3);
  background: rgba(18, 18, 23, 0.85);
  backdrop-filter: blur(16px);
  border-radius: var(--radius-lg);
  position: relative;
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
  box-shadow: 0 0 60px rgba(168, 85, 247, 0.15), inset 0 0 20px rgba(0, 0, 0, 0.5);
}

/* Inner Grid Lines */
.radar-grid-overlay {
  position: absolute;
  inset: 0;
  background-image: 
    linear-gradient(to right, rgba(168, 85, 247, 0.12) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(168, 85, 247, 0.12) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
}

/* Dashed Radar Circle */
.radar-circle {
  width: 260px;
  height: 260px;
  border: 1px dashed rgba(168, 85, 247, 0.45);
  border-radius: 50%;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  animation: rotateCircle 25s linear infinite;
}

@keyframes rotateCircle {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Glowing Purple Active Node Dot */
.active-node-dot {
  position: absolute;
  right: -7px;
  top: 50%;
  transform: translateY(-50%);
  width: 14px;
  height: 14px;
  background: #c084fc;
  border-radius: 50%;
  box-shadow: 0 0 16px #a855f7, 0 0 30px #a855f7;
}

.node-pulse-ring {
  position: absolute;
  top: -8px;
  left: -8px;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 2px solid var(--accent-purple);
  animation: pulse 2s ease-out infinite;
}

@keyframes pulse {
  0% { transform: scale(0.5); opacity: 1; }
  100% { transform: scale(2.4); opacity: 0; }
}

/* NODE_ACTIVE Label Badge */
.node-badge {
  position: absolute;
  top: -36px;
  left: -20px;
  font-family: monospace, SFMono-Regular, Consolas, "Liberation Mono", Menlo;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: #c084fc;
  background: rgba(9, 9, 11, 0.95);
  padding: 4px 10px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.6);
  white-space: nowrap;
  animation: counterRotate 25s linear infinite;
}

@keyframes counterRotate {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(-360deg); }
}

/* Features Grid */
.features-section {
  padding: 100px 0;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

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

.feature-card:hover {
  transform: translateY(-5px);
  border-color: var(--accent-purple);
  box-shadow: 0 10px 30px rgba(168, 85, 247, 0.15);
  background: var(--bg-card-hover);
}

.feature-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: rgba(168, 85, 247, 0.1);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-purple);
  font-size: 1.5rem;
  margin-bottom: 20px;
}

.feature-card h3 {
  font-size: 1.25rem;
  margin-bottom: 12px;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Pricing Section */
.pricing-section {
  padding: 100px 0;
  background: linear-gradient(180deg, transparent 0%, rgba(18, 18, 23, 0.5) 50%, transparent 100%);
}

.pricing-tabs {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-bottom: 40px;
}

.tab-btn {
  padding: 10px 24px;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-muted);
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

.tab-btn.active {
  background: var(--accent-purple);
  color: #fff;
  border-color: var(--accent-purple);
  box-shadow: 0 0 20px var(--accent-purple-glow);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}

.price-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition);
}

.price-card.popular {
  border-color: var(--accent-purple);
  background: linear-gradient(180deg, rgba(168, 85, 247, 0.1) 0%, rgba(18, 18, 23, 0.8) 100%);
  box-shadow: 0 0 30px rgba(168, 85, 247, 0.2);
}

.popular-badge {
  position: absolute;
  top: -12px;
  right: 24px;
  background: linear-gradient(135deg, var(--accent-purple) 0%, var(--accent-cyan) 100%);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: var(--radius-full);
  text-transform: uppercase;
}

.price-card h3 {
  font-size: 1.3rem;
  margin-bottom: 8px;
}

.price-amount {
  font-size: 2.2rem;
  font-weight: 800;
  color: #fff;
  margin: 16px 0;
}

.price-amount span {
  font-size: 0.9rem;
  color: var(--text-dim);
  font-weight: 400;
}

.price-features {
  list-style: none;
  margin: 24px 0;
  flex: 1;
}

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

.price-features li svg {
  color: var(--accent-green);
  flex-shrink: 0;
}

/* Articles Grid / Guide Section */
.articles-section {
  padding: 100px 0;
}

.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);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition);
}

.article-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent-purple);
  box-shadow: 0 10px 25px rgba(168, 85, 247, 0.15);
}

.article-tag {
  font-size: 0.8rem;
  color: var(--accent-purple);
  font-weight: 600;
  margin-bottom: 12px;
}

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

.article-card h3 a {
  color: #fff;
  text-decoration: none;
  transition: var(--transition);
}

.article-card h3 a:hover {
  color: var(--accent-purple);
}

.article-card p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 20px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-dim);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 16px;
}

.read-more {
  color: var(--accent-purple);
  text-decoration: none;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.read-more:hover {
  text-decoration: underline;
}

/* Customer Reviews / Testimonials */
.reviews-section {
  padding: 100px 0;
  background: rgba(18, 18, 23, 0.4);
}

.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
}

.review-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent-purple) 0%, var(--accent-cyan) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: #fff;
}

.user-info h4 {
  font-size: 1rem;
}

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

.stars {
  color: #f59e0b;
  margin-bottom: 12px;
  font-size: 0.9rem;
}

.review-content {
  color: var(--text-muted);
  font-size: 0.92rem;
  line-height: 1.6;
}

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

.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

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

.faq-question {
  padding: 20px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  font-weight: 600;
  font-size: 1.05rem;
  color: #fff;
}

.faq-icon {
  color: var(--accent-purple);
  transition: transform 0.3s ease;
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  padding: 0 24px;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 300px;
  padding: 0 24px 20px 24px;
}

/* Footer & PBN Links (Core Requirement 2) */
footer {
  background: #050507;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding: 60px 0 30px 0;
  text-align: center;
}

.footer-brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-bottom: 20px;
}

.footer-brand span {
  font-size: 1.4rem;
  font-weight: 800;
  color: #fff;
}

.footer-desc {
  color: var(--text-dim);
  font-size: 0.9rem;
  max-width: 500px;
  margin: 0 auto 30px auto;
}

/* Low-profile, elegant, small font PBN links section */
.footer-pbn-links {
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 24px;
  margin-top: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  font-size: 0.82rem;
  color: var(--text-dim);
}

.pbn-label {
  color: var(--text-dim);
}

.pbn-link {
  color: var(--text-muted);
  text-decoration: none;
  transition: var(--transition);
}

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

.copyright {
  color: var(--text-dim);
  font-size: 0.8rem;
  margin-top: 20px;
}

/* Article Page Layout Styling */
.article-header {
  padding-top: 140px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.article-content {
  padding: 60px 0;
  max-width: 860px;
  margin: 0 auto;
  font-size: 1.05rem;
  line-height: 1.8;
  color: #d4d4d8;
}

.article-content h2 {
  font-size: 1.75rem;
  margin: 40px 0 20px 0;
  color: #fff;
  border-left: 4px solid var(--accent-purple);
  padding-left: 16px;
}

.article-content h3 {
  font-size: 1.35rem;
  margin: 28px 0 16px 0;
  color: #f4f4f5;
}

.article-content p {
  margin-bottom: 20px;
}

.article-content ul, .article-content ol {
  margin: 0 0 24px 24px;
}

.article-content li {
  margin-bottom: 8px;
}

.article-content blockquote {
  border-left: 4px solid var(--accent-cyan);
  background: rgba(6, 182, 212, 0.05);
  padding: 16px 24px;
  border-radius: var(--radius-sm);
  margin: 24px 0;
  color: #e4e4e7;
  font-style: italic;
}

.article-cta-box {
  background: linear-gradient(135deg, rgba(168, 85, 247, 0.15) 0%, rgba(18, 18, 23, 0.9) 100%);
  border: 1px solid var(--accent-purple);
  border-radius: var(--radius-lg);
  padding: 32px;
  margin: 40px 0;
  text-align: center;
}

.article-cta-box h3 {
  color: #fff;
  font-size: 1.5rem;
  margin-bottom: 12px;
}

.article-cta-box p {
  color: var(--text-muted);
  margin-bottom: 24px;
}

.related-articles {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding-top: 40px;
  margin-top: 60px;
}

/* Responsive adjustments */
@media (max-width: 992px) {
  .hero {
    grid-template-columns: 1fr;
    text-align: center;
    padding-top: 120px;
  }

  .hero-title {
    font-size: 2.5rem;
  }

  .hero-actions {
    justify-content: center;
  }

  .hero-stats {
    max-width: 500px;
    margin: 0 auto;
  }

  .nav-links {
    display: none;
  }
}

@media (max-width: 600px) {
  .hero-title {
    font-size: 2rem;
  }

  .section-title {
    font-size: 1.75rem;
  }
}