/* ==========================================================================
   AllBlue.sbs - Master Stylesheet
   Theme: All Blue (深海电光蓝 / 极光流体 CSS Design System)
   ========================================================================== */

:root {
  --bg-main: #040914;
  --bg-surface: #091326;
  --bg-surface-elevated: #0f1c36;
  --primary-blue: #0072ff;
  --cyan-glow: #00f0ff;
  --accent-sky: #38bdf8;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --border-blue: rgba(0, 240, 255, 0.15);
  --border-highlight: rgba(0, 240, 255, 0.4);
  --glass-bg: rgba(9, 19, 38, 0.65);
  --glass-border: rgba(255, 255, 255, 0.08);
  --card-glow: 0 0 25px rgba(0, 114, 255, 0.25);
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

html {
  scroll-behavior: smooth;
  font-family: var(--font-family);
  background-color: var(--bg-main);
  color: var(--text-main);
  overflow-x: hidden;
}

body {
  position: relative;
  min-height: 100vh;
  line-height: 1.6;
  background: radial-gradient(circle at 50% 0%, #0a1b3d 0%, #040914 70%);
}

/* Custom Cursor Trail Canvas */
#cursor-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 9999;
}

/* Background Animated Gradient Mesh */
.bg-mesh {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
  opacity: 0.6;
  background: 
    radial-gradient(circle at 20% 20%, rgba(0, 114, 255, 0.15) 0%, transparent 40%),
    radial-gradient(circle at 80% 70%, rgba(0, 240, 255, 0.1) 0%, transparent 40%);
}

.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 20px;
  position: relative;
  z-index: 2;
}

/* Utility Classes */
.text-cyan { color: var(--cyan-glow); }
.text-blue { color: var(--primary-blue); }
.gradient-text {
  background: linear-gradient(135deg, #ffffff 0%, var(--cyan-glow) 50%, var(--primary-blue) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: 50px;
  text-decoration: none;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  cursor: pointer;
}
.btn-primary {
  background: linear-gradient(135deg, var(--primary-blue) 0%, var(--cyan-glow) 100%);
  color: #040914;
  box-shadow: 0 0 20px rgba(0, 240, 255, 0.4);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 30px rgba(0, 240, 255, 0.7);
  filter: brightness(1.1);
}
.btn-outline {
  background: rgba(0, 114, 255, 0.1);
  border: 1px solid var(--border-highlight);
  color: var(--cyan-glow);
}
.btn-outline:hover {
  background: rgba(0, 240, 255, 0.2);
  color: #ffffff;
  box-shadow: 0 0 20px rgba(0, 240, 255, 0.3);
}

/* Navbar */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(4, 9, 20, 0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--glass-border);
  padding: 16px 0;
}
.nav-wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  font-size: 1.5rem;
  font-weight: 800;
  color: #ffffff;
  letter-spacing: -0.5px;
}
.brand-logo img {
  width: 38px;
  height: 38px;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}
.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s ease;
}
.nav-links a:hover {
  color: var(--cyan-glow);
}

/* Hero Section */
.hero {
  padding: 100px 0 60px;
  text-align: center;
  position: relative;
}
.hero-tag {
  display: inline-block;
  padding: 6px 18px;
  background: rgba(0, 240, 255, 0.1);
  border: 1px solid var(--border-highlight);
  border-radius: 30px;
  color: var(--cyan-glow);
  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;
}
.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 760px;
  margin: 0 auto 36px;
}
.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-bottom: 50px;
}
.hero-stats {
  display: flex;
  justify-content: center;
  gap: 40px;
  padding-top: 30px;
  border-top: 1px solid var(--glass-border);
  max-width: 800px;
  margin: 0 auto;
}
.stat-item h3 {
  font-size: 2rem;
  font-weight: 800;
  color: var(--cyan-glow);
}
.stat-item p {
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* Features Section */
.features-section {
  padding: 80px 0;
}
.section-header {
  text-align: center;
  margin-bottom: 50px;
}
.section-header h2 {
  font-size: 2.25rem;
  font-weight: 800;
  margin-bottom: 12px;
}
.section-header p {
  color: var(--text-muted);
  font-size: 1.1rem;
}
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}
.feature-card {
  background: var(--bg-surface);
  border: 1px solid var(--glass-border);
  padding: 32px;
  border-radius: var(--radius-md);
  transition: all 0.3s ease;
}
.feature-card:hover {
  transform: translateY(-5px);
  border-color: var(--border-highlight);
  box-shadow: var(--card-glow);
}
.feature-icon {
  width: 54px;
  height: 54px;
  background: rgba(0, 114, 255, 0.15);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  color: var(--cyan-glow);
  font-size: 1.5rem;
}

/* Horizontal Pricing Section ("价格格式你帮我弄成一排") */
.pricing-section {
  padding: 80px 0;
  background: rgba(9, 19, 38, 0.4);
}
.pricing-container {
  display: flex;
  flex-direction: row;
  justify-content: space-between;
  align-items: stretch;
  gap: 20px;
  overflow-x: auto;
  padding-bottom: 20px;
}
.pricing-card {
  flex: 1 1 0;
  min-width: 260px;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-blue);
  border-radius: var(--radius-md);
  padding: 32px 24px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all 0.3s ease;
}
.pricing-card:hover {
  transform: translateY(-8px);
  border-color: var(--cyan-glow);
  box-shadow: 0 10px 30px rgba(0, 240, 255, 0.25);
}
.pricing-card.popular {
  border: 2px solid var(--cyan-glow);
  background: linear-gradient(180deg, rgba(0, 114, 255, 0.15) 0%, var(--bg-surface-elevated) 100%);
}
.popular-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(90deg, var(--primary-blue), var(--cyan-glow));
  color: #040914;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 4px 14px;
  border-radius: 20px;
  text-transform: uppercase;
  letter-spacing: 1px;
}
.plan-name {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 8px;
}
.plan-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 20px;
  min-height: 40px;
}
.plan-price {
  font-size: 2.25rem;
  font-weight: 900;
  color: var(--cyan-glow);
  margin-bottom: 24px;
}
.plan-price span {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 400;
}
.plan-features {
  list-style: none;
  margin-bottom: 30px;
  flex-grow: 1;
}
.plan-features li {
  font-size: 0.9rem;
  color: var(--text-main);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.plan-features li::before {
  content: "✓";
  color: var(--cyan-glow);
  font-weight: bold;
}
.pricing-card .btn {
  width: 100%;
}

/* User Reviews Section */
.reviews-section {
  padding: 80px 0;
}
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}
.review-card {
  background: var(--bg-surface);
  border: 1px solid var(--glass-border);
  padding: 28px;
  border-radius: var(--radius-md);
}
.review-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 16px;
}
.avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary-blue), var(--cyan-glow));
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: #040914;
  font-size: 1.1rem;
}
.user-info h4 {
  font-size: 1rem;
  font-weight: 700;
}
.user-info p {
  font-size: 0.8rem;
  color: var(--text-dim);
}
.star-rating {
  color: #f59e0b;
  margin-bottom: 12px;
  font-size: 0.9rem;
}
.review-text {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* FAQ Accordion Section */
.faq-section {
  padding: 80px 0;
  background: rgba(9, 19, 38, 0.4);
}
.faq-list {
  max-width: 840px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.faq-item {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: border-color 0.3s ease;
}
.faq-question {
  padding: 20px 24px;
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
}
.faq-question::after {
  content: "+";
  font-size: 1.5rem;
  color: var(--cyan-glow);
  transition: transform 0.3s ease;
}
.faq-item.active {
  border-color: var(--border-highlight);
}
.faq-item.active .faq-question::after {
  content: "-";
  transform: rotate(180deg);
}
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.4s 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;
}

/* SEO Articles Grid */
.articles-section {
  padding: 80px 0;
}
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 28px;
}
.article-card {
  background: var(--bg-surface);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all 0.3s ease;
}
.article-card:hover {
  transform: translateY(-5px);
  border-color: var(--border-highlight);
  box-shadow: var(--card-glow);
}
.article-tag {
  font-size: 0.75rem;
  color: var(--cyan-glow);
  text-transform: uppercase;
  letter-spacing: 1px;
  font-weight: 700;
  margin-bottom: 10px;
}
.article-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
  line-height: 1.4;
}
.article-card h3 a {
  color: var(--text-main);
  text-decoration: none;
  transition: color 0.3s ease;
}
.article-card h3 a:hover {
  color: var(--cyan-glow);
}
.article-excerpt {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 20px;
  line-height: 1.6;
}
.article-read-more {
  color: var(--accent-sky);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.article-read-more:hover {
  color: var(--cyan-glow);
}

/* Core Task 2: PBN SEO Footer Styling */
footer {
  background: #02050c;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding: 40px 0 24px;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-dim);
}
.footer-main {
  margin-bottom: 24px;
}
.footer-logo {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--text-main);
  font-weight: 700;
  text-decoration: none;
  margin-bottom: 12px;
}
.footer-links {
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  margin-bottom: 24px;
  list-style: none;
}
.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
}
.footer-links a:hover {
  color: var(--cyan-glow);
}

/* Low-profile PBN Link Injection Section */
.pbn-link-zone {
  border-top: 1px dashed rgba(255, 255, 255, 0.06);
  padding-top: 20px;
  margin-top: 20px;
  font-size: 0.75rem;
  color: #475569;
}
.pbn-link-zone h5 {
  font-size: 0.75rem;
  font-weight: 600;
  color: #64748b;
  margin-bottom: 8px;
}
.pbn-links-list {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px 18px;
  list-style: none;
}
.pbn-links-list a {
  color: #64748b;
  text-decoration: none;
  transition: color 0.2s ease;
}
.pbn-links-list a:hover {
  color: var(--accent-sky);
}

/* Responsive Breakpoints */
@media (max-width: 992px) {
  .hero-title { font-size: 2.75rem; }
  .pricing-container {
    flex-wrap: wrap;
  }
  .pricing-card {
    flex: 1 1 calc(50% - 10px);
  }
}

@media (max-width: 640px) {
  .hero-title { font-size: 2rem; }
  .hero-subtitle { font-size: 1rem; }
  .hero-actions { flex-direction: column; }
  .hero-stats { flex-direction: column; gap: 20px; }
  .pricing-card {
    flex: 1 1 100%;
  }
  .nav-links { display: none; }
}