/* ==========================================================================
   Stardust Cloud (星尘云) - CSS Design System & Stylesheet
   Domain: stardustcloud.cfd
   ========================================================================== */

:root {
  --bg-dark: #060814;
  --bg-card: rgba(15, 23, 42, 0.65);
  --bg-card-hover: rgba(30, 41, 59, 0.85);
  --border-color: rgba(96, 165, 250, 0.18);
  --border-glow: rgba(96, 165, 250, 0.45);
  
  --primary-blue: #38bdf8;
  --accent-purple: #a855f7;
  --neon-cyan: #22d3ee;
  --text-main: #f1f5f9;
  --text-muted: #94a3b8;
  --text-light: #cbd5e1;
  
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  --shadow-glow: 0 10px 30px -10px rgba(56, 189, 248, 0.3);
}

/* Reset & Global */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

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

/* Canvas Canvas Background */
#stardust-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  pointer-events: none;
}

/* White-Blue Gradient Text */
.gradient-text {
  background: linear-gradient(135deg, #ffffff 0%, #7dd3fc 35%, #38bdf8 65%, #c084fc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

.gradient-text-subtle {
  background: linear-gradient(135deg, #ffffff 0%, #cbd5e1 50%, #94a3b8 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header & Navbar */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(6, 8, 20, 0.75);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  padding: 15px 0;
  transition: all 0.3s ease;
}

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

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, #38bdf8, #a855f7);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.5);
  transition: transform 0.3s ease;
}

.brand-logo:hover .logo-icon {
  transform: rotate(15deg) scale(1.05);
}

.logo-title {
  font-size: 1.4rem;
  font-weight: 800;
  letter-spacing: 0.5px;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 24px;
  list-style: none;
}

.nav-link {
  color: var(--text-light);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.3s ease;
}

.nav-link:hover {
  color: var(--primary-blue);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

/* CTA Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 22px;
  border-radius: 30px;
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  border: 1px solid transparent;
}

.btn-primary {
  background: linear-gradient(135deg, #0284c7 0%, #2563eb 50%, #7c3aed 100%);
  color: #ffffff;
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(124, 58, 237, 0.6);
  border-color: rgba(255, 255, 255, 0.3);
}

.btn-recommend {
  background: linear-gradient(135deg, rgba(236, 72, 153, 0.15), rgba(168, 85, 247, 0.25));
  border: 1px solid rgba(236, 72, 153, 0.5);
  color: #f472b6;
  box-shadow: 0 0 15px rgba(236, 72, 153, 0.2);
}

.btn-recommend:hover {
  background: linear-gradient(135deg, rgba(236, 72, 153, 0.3), rgba(168, 85, 247, 0.4));
  color: #ffffff;
  transform: translateY(-2px);
  box-shadow: 0 0 25px rgba(236, 72, 153, 0.5);
}

.btn-outline {
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  backdrop-filter: blur(8px);
}

.btn-outline:hover {
  border-color: var(--primary-blue);
  color: var(--primary-blue);
  box-shadow: 0 0 15px rgba(56, 189, 248, 0.2);
}

.btn-lg {
  padding: 14px 34px;
  font-size: 1.1rem;
  border-radius: 40px;
}

/* Hero Section */
.hero-section {
  padding: 160px 0 90px;
  text-align: center;
  position: relative;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: 20px;
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.3);
  color: var(--primary-blue);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 24px;
  backdrop-filter: blur(5px);
}

.badge-pulse {
  width: 8px;
  height: 8px;
  background-color: #22c55e;
  border-radius: 50%;
  box-shadow: 0 0 10px #22c55e;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.7); }
  70% { transform: scale(1.1); box-shadow: 0 0 0 10px rgba(34, 197, 94, 0); }
  100% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(34, 197, 94, 0); }
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 900;
  line-height: 1.25;
  margin-bottom: 24px;
  letter-spacing: -1px;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 800px;
  margin: 0 auto 40px;
  line-height: 1.7;
}

.hero-buttons {
  display: flex;
  justify-content: center;
  gap: 18px;
  margin-bottom: 60px;
  flex-wrap: wrap;
}

/* Stats Counter Banner (实时节点和下载人数) */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  max-width: 1000px;
  margin: 0 auto;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 24px 20px;
  text-align: center;
  backdrop-filter: blur(12px);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  transition: all 0.3s ease;
}

.stat-card:hover {
  border-color: var(--primary-blue);
  transform: translateY(-5px);
  box-shadow: var(--shadow-glow);
}

.stat-icon {
  font-size: 1.8rem;
  margin-bottom: 10px;
  display: block;
}

.stat-number {
  font-size: 2.2rem;
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 4px;
  font-variant-numeric: tabular-nums;
}

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

/* Section Common */
.section {
  padding: 90px 0;
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 60px;
}

.section-title {
  font-size: 2.4rem;
  font-weight: 800;
  margin-bottom: 16px;
}

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

/* Floating Pricing Section (价格表全部要浮动展示) */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 28px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 24px;
  padding: 36px 28px;
  display: flex;
  flex-direction: column;
  position: relative;
  backdrop-filter: blur(16px);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  animation: floatCard 6s ease-in-out infinite;
}

.pricing-card:nth-child(1) { animation-delay: 0s; }
.pricing-card:nth-child(2) { animation-delay: 1.5s; }
.pricing-card:nth-child(3) { animation-delay: 3s; }
.pricing-card:nth-child(4) { animation-delay: 4.5s; }

@keyframes floatCard {
  0%, 100% {
    transform: translateY(0px) rotate(0deg);
  }
  50% {
    transform: translateY(-14px) rotate(0.6deg);
  }
}

.pricing-card:hover {
  animation-play-state: paused;
  transform: translateY(-18px) scale(1.02);
  border-color: var(--primary-blue);
  box-shadow: 0 20px 50px rgba(56, 189, 248, 0.25);
}

.pricing-card.featured {
  border: 2px solid var(--primary-blue);
  background: linear-gradient(180deg, rgba(30, 41, 59, 0.9) 0%, rgba(15, 23, 42, 0.95) 100%);
  box-shadow: 0 0 35px rgba(56, 189, 248, 0.3);
}

.popular-badge {
  position: absolute;
  top: -14px;
  right: 24px;
  background: linear-gradient(135deg, #0284c7, #a855f7);
  color: #ffffff;
  padding: 4px 14px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  box-shadow: 0 4px 15px rgba(168, 85, 247, 0.4);
}

.pricing-header {
  margin-bottom: 24px;
  text-align: center;
}

.plan-name {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: #ffffff;
}

.plan-price {
  font-size: 2.8rem;
  font-weight: 900;
  color: #ffffff;
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 4px;
}

.plan-price span {
  font-size: 1rem;
  color: var(--text-muted);
  font-weight: 500;
}

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

.pricing-features li {
  padding: 10px 0;
  border-bottom: 1px dashed rgba(255, 255, 255, 0.08);
  color: var(--text-light);
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  gap: 10px;
}

.pricing-features li::before {
  content: "✓";
  color: var(--neon-cyan);
  font-weight: bold;
}

/* Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 30px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  padding: 32px;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

.feature-card:hover {
  transform: translateY(-6px);
  border-color: rgba(168, 85, 247, 0.4);
  box-shadow: 0 10px 30px rgba(168, 85, 247, 0.15);
}

.feature-icon {
  width: 56px;
  height: 56px;
  background: rgba(56, 189, 248, 0.1);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 20px;
  border: 1px solid rgba(56, 189, 248, 0.2);
}

.feature-title {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: #ffffff;
}

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

/* Article Matrix Grid (文章展示与内链跳转) */
.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: 18px;
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all 0.3s ease;
  text-decoration: none;
  color: inherit;
}

.article-card:hover {
  transform: translateY(-6px);
  border-color: var(--primary-blue);
  box-shadow: var(--shadow-glow);
}

.article-tag {
  align-self: flex-start;
  padding: 4px 12px;
  border-radius: 12px;
  background: rgba(168, 85, 247, 0.15);
  border: 1px solid rgba(168, 85, 247, 0.3);
  color: #c084fc;
  font-size: 0.78rem;
  font-weight: 600;
  margin-bottom: 14px;
}

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

.article-excerpt {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 20px;
  line-height: 1.6;
}

.article-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.82rem;
  color: var(--text-light);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 14px;
}

/* User Reviews (用户评价) */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 18px;
  padding: 26px;
  backdrop-filter: blur(10px);
}

.review-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 16px;
}

.avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, #38bdf8, #a855f7);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  color: #ffffff;
}

.reviewer-info h4 {
  color: #ffffff;
  font-size: 1rem;
  font-weight: 700;
}

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

.stars {
  color: #fbbf24;
  margin-bottom: 10px;
}

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

/* FAQ Accordion (常见问题FAQ) */
.faq-container {
  max-width: 840px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 14px;
  margin-bottom: 16px;
  overflow: hidden;
  transition: border-color 0.3s ease;
}

.faq-question {
  padding: 20px 24px;
  font-weight: 700;
  font-size: 1.05rem;
  color: #ffffff;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
}

.faq-icon {
  font-size: 1.2rem;
  transition: transform 0.3s ease;
  color: var(--primary-blue);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.4s ease;
  padding: 0 24px;
  color: var(--text-light);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active {
  border-color: var(--primary-blue);
}

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

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

/* Footer & PBN Backlink Pipeline (核心任务 2: 页脚 PBN 权重通道) */
footer {
  background: rgba(3, 5, 12, 0.95);
  border-top: 1px solid var(--border-color);
  padding: 60px 0 30px;
  text-align: center;
}

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

.footer-nav {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  justify-content: center;
}

.footer-nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.3s ease;
}

.footer-nav a:hover {
  color: var(--primary-blue);
}

/* PBN Friendly Link Bar - Small, subtle, elegant, dofollow */
.pbn-links-bar {
  margin-top: 20px;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  font-size: 0.82rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.pbn-link {
  color: #64748b;
  text-decoration: none;
  transition: color 0.3s ease;
  font-weight: 500;
}

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

.copyright {
  font-size: 0.85rem;
  color: #475569;
}

/* Responsive Layout */
@media (max-width: 768px) {
  .hero-title {
    font-size: 2.2rem;
  }
  .hero-subtitle {
    font-size: 1rem;
  }
  .nav-menu {
    display: none;
  }
  .pricing-grid {
    grid-template-columns: 1fr;
  }
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}