/* ==========================================================================
   自由猫 FreeCat - Abyssal Stealth (深海声呐与静音潜航风) Design System
   Domain: freecatnet.homes
   ========================================================================== */

:root {
  --bg-abyssal: #050C1A;
  --bg-depths: #081226;
  --bg-hull: #0B1A30;
  --bg-hull-card: rgba(11, 26, 48, 0.75);
  --bg-gauge: rgba(5, 12, 26, 0.85);
  
  --electric-blue: #00F0FF;
  --electric-blue-dark: #00A8FF;
  --electric-blue-glow: rgba(0, 240, 255, 0.4);
  --electric-blue-subtle: rgba(0, 240, 255, 0.08);
  
  --sonar-cyan: #00FFC8;
  --sonar-green: #00FF9D;
  --warning-amber: #FFB800;
  --danger-crimson: #FF3B30;
  
  --text-main: #E2E8F0;
  --text-muted: #94A3B8;
  --text-dim: #64748B;
  --border-hull: rgba(0, 240, 255, 0.18);
  --border-glow: rgba(0, 240, 255, 0.45);

  --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  
  --radius-window: 16px;
  --radius-hatch: 8px;
  --shadow-hull: 0 10px 30px -10px rgba(0, 0, 0, 0.7), inset 0 1px 1px rgba(255, 255, 255, 0.05);
  --shadow-electric: 0 0 20px rgba(0, 240, 255, 0.35);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-abyssal);
  color: var(--text-main);
  font-family: var(--font-body);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

body {
  background-color: var(--bg-abyssal);
  position: relative;
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
  cursor: default;
}

/* Custom Sonar Radar Canvas Background */
#sonar-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -1;
  pointer-events: none;
  opacity: 0.85;
}

/* Tail Fin Cursor Trail */
.cursor-fin {
  position: fixed;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--electric-blue) 0%, rgba(0, 240, 255, 0) 70%);
  pointer-events: none;
  transform: translate(-50%, -50%);
  z-index: 9999;
  transition: transform 0.05s ease-out;
  box-shadow: 0 0 12px var(--electric-blue);
}

.cursor-fin-trail {
  position: fixed;
  pointer-events: none;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--electric-blue);
  opacity: 0.6;
  z-index: 9998;
  transform: translate(-50%, -50%);
  transition: width 0.3s, height 0.3s, opacity 0.3s;
}

/* Typography & Links */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: #FFFFFF;
  font-weight: 700;
  line-height: 1.25;
}

a {
  color: var(--electric-blue);
  text-decoration: none;
  transition: all 0.25s ease;
}

a:hover {
  color: #FFFFFF;
  text-shadow: 0 0 8px var(--electric-blue);
}

.container {
  width: 100%;
  max-width: 1240px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Submarine Watertight Window Container / Panel Style */
.hull-panel {
  background: var(--bg-hull-card);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-hull);
  border-radius: var(--radius-window);
  box-shadow: var(--shadow-hull);
  position: relative;
  overflow: hidden;
  transition: transform 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.hull-panel::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--electric-blue), transparent);
  opacity: 0.6;
}

.hull-panel:hover {
  border-color: var(--border-glow);
  box-shadow: 0 12px 40px -10px rgba(0, 240, 255, 0.2), inset 0 1px 1px rgba(255, 255, 255, 0.1);
}

/* Submarine Instrument Gauge Window Decoration */
.gauge-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  background: rgba(5, 12, 26, 0.6);
  border-bottom: 1px solid var(--border-hull);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--electric-blue);
  letter-spacing: 1px;
  text-transform: uppercase;
}

.gauge-dots {
  display: flex;
  gap: 6px;
}

.gauge-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--text-dim);
}

.gauge-dot.active {
  background-color: var(--sonar-cyan);
  box-shadow: 0 0 8px var(--sonar-cyan);
}

/* Electric Glow CTA Buttons */
.btn-electric {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 32px;
  background: linear-gradient(135deg, rgba(0, 240, 255, 0.2) 0%, rgba(0, 168, 255, 0.4) 100%);
  border: 1px solid var(--electric-blue);
  color: #FFFFFF;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.5px;
  border-radius: 50px;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  box-shadow: 0 0 15px rgba(0, 240, 255, 0.3);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  text-shadow: 0 0 5px rgba(0, 240, 255, 0.6);
}

.btn-electric::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(0, 240, 255, 0.4) 0%, transparent 60%);
  opacity: 0;
  transition: opacity 0.3s ease;
  transform: scale(0.5);
}

.btn-electric:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 30px rgba(0, 240, 255, 0.7), 0 0 50px rgba(0, 168, 255, 0.4);
  border-color: #FFFFFF;
  color: #FFFFFF;
}

.btn-electric:hover::after {
  opacity: 1;
  transform: scale(1);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  background: rgba(11, 26, 48, 0.6);
  border: 1px solid var(--border-hull);
  color: var(--text-main);
  font-family: var(--font-heading);
  font-weight: 600;
  border-radius: 50px;
  transition: all 0.3s ease;
}

.btn-secondary:hover {
  background: rgba(0, 240, 255, 0.1);
  border-color: var(--electric-blue);
  color: #FFFFFF;
}

/* Header & Navbar */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(5, 12, 26, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(0, 240, 255, 0.12);
  transition: all 0.3s ease;
}

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

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 800;
  color: #FFFFFF;
  letter-spacing: 0.5px;
}

.brand-badge {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: linear-gradient(135deg, #00F0FF, #0055FF);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 12px rgba(0, 240, 255, 0.5);
  color: #050C1A;
  font-weight: 900;
  font-size: 1.2rem;
}

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

.nav-link {
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.25s ease;
}

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

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-main);
  font-size: 1.5rem;
  cursor: pointer;
}

/* Hero Section */
.hero-section {
  padding: 160px 0 100px;
  position: relative;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: rgba(0, 240, 255, 0.08);
  border: 1px solid rgba(0, 240, 255, 0.3);
  border-radius: 30px;
  color: var(--electric-blue);
  font-size: 0.85rem;
  font-family: var(--font-mono);
  margin-bottom: 24px;
}

.sonar-ping {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--sonar-green);
  box-shadow: 0 0 8px var(--sonar-green);
  animation: ping 1.8s cubic-bezier(0, 0, 0.2, 1) infinite;
}

@keyframes ping {
  75%, 100% {
    transform: scale(2.2);
    opacity: 0;
  }
}

.hero-title {
  font-size: 3.2rem;
  line-height: 1.15;
  margin-bottom: 20px;
  background: linear-gradient(180deg, #FFFFFF 0%, #B0D0FF 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-title span {
  background: linear-gradient(135deg, var(--electric-blue) 0%, var(--sonar-cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin-bottom: 36px;
  max-width: 580px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.stat-value {
  font-size: 1.8rem;
  font-family: var(--font-heading);
  font-weight: 800;
  color: var(--electric-blue);
  line-height: 1;
}

.stat-label {
  font-size: 0.825rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* Submarine Dashboard Card Component */
.submarine-window {
  background: var(--bg-gauge);
  border: 1px solid var(--border-hull);
  border-radius: 20px;
  padding: 24px;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.6), inset 0 0 20px rgba(0, 240, 255, 0.05);
}

.node-radar-box {
  position: relative;
  min-height: 320px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.radar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px dashed var(--border-hull);
}

.radar-title {
  font-family: var(--font-mono);
  color: var(--sonar-cyan);
  font-size: 0.9rem;
  letter-spacing: 1px;
}

.node-status-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.node-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background: rgba(11, 26, 48, 0.5);
  border: 1px solid rgba(0, 240, 255, 0.1);
  border-radius: 10px;
  font-size: 0.9rem;
}

.node-info {
  display: flex;
  align-items: center;
  gap: 10px;
}

.flag {
  font-size: 1.1rem;
}

.node-name {
  font-weight: 600;
  color: var(--text-main);
}

.node-ping {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--sonar-green);
  background: rgba(0, 255, 157, 0.1);
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 0.8rem;
}

/* Feature Cards Grid */
.section-padding {
  padding: 100px 0;
}

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

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

.section-desc {
  color: var(--text-muted);
  font-size: 1.05rem;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.feature-card {
  padding: 32px;
}

.feature-icon {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  background: rgba(0, 240, 255, 0.1);
  border: 1px solid rgba(0, 240, 255, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  color: var(--electric-blue);
  margin-bottom: 20px;
}

.feature-title {
  font-size: 1.3rem;
  margin-bottom: 12px;
}

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

/* Pricing Section */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
  align-items: stretch;
}

.price-card {
  padding: 36px 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
}

.price-card.popular {
  border-color: var(--electric-blue);
  box-shadow: 0 0 35px rgba(0, 240, 255, 0.25);
}

.popular-badge {
  position: absolute;
  top: 16px;
  right: 16px;
  background: var(--electric-blue);
  color: #050C1A;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 4px 12px;
  border-radius: 20px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

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

.plan-price {
  font-size: 2.5rem;
  font-family: var(--font-heading);
  font-weight: 800;
  color: #FFFFFF;
  margin-bottom: 16px;
}

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

.plan-features {
  list-style: none;
  margin: 24px 0 32px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

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

.plan-features li::before {
  content: '✓';
  color: var(--sonar-green);
  font-weight: 900;
}

/* SEO Articles Section & Modal View */
.articles-wrapper {
  margin-top: 40px;
}

.article-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 30px;
  justify-content: center;
}

.tab-btn {
  padding: 10px 20px;
  background: rgba(11, 26, 48, 0.6);
  border: 1px solid var(--border-hull);
  border-radius: 30px;
  color: var(--text-muted);
  font-size: 0.875rem;
  cursor: pointer;
  transition: all 0.25s ease;
}

.tab-btn.active, .tab-btn:hover {
  background: rgba(0, 240, 255, 0.15);
  border-color: var(--electric-blue);
  color: #FFFFFF;
  box-shadow: 0 0 12px rgba(0, 240, 255, 0.2);
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 24px;
}

.article-card {
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  cursor: pointer;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.8rem;
  color: var(--electric-blue);
  margin-bottom: 12px;
  font-family: var(--font-mono);
}

.article-card-title {
  font-size: 1.15rem;
  margin-bottom: 12px;
  line-height: 1.4;
}

.article-excerpt {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 20px;
  line-height: 1.6;
}

.read-more {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--electric-blue);
  display: flex;
  align-items: center;
  gap: 6px;
}

/* Modal Article Reader */
.article-modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(3, 8, 18, 0.9);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

.article-modal.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-content {
  width: 90%;
  max-width: 900px;
  max-height: 85vh;
  background: var(--bg-depths);
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-window);
  padding: 40px;
  overflow-y: auto;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.9);
  position: relative;
}

.close-modal {
  position: absolute;
  top: 20px;
  right: 24px;
  background: rgba(255, 255, 255, 0.1);
  border: none;
  color: #FFFFFF;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s;
}

.close-modal:hover {
  background: var(--danger-crimson);
}

.article-full-body {
  margin-top: 24px;
  color: var(--text-main);
  line-height: 1.8;
  font-size: 1rem;
}

.article-full-body h2 {
  font-size: 1.5rem;
  margin: 28px 0 16px;
  color: var(--electric-blue);
  border-left: 3px solid var(--electric-blue);
  padding-left: 12px;
}

.article-full-body h3 {
  font-size: 1.2rem;
  margin: 20px 0 12px;
  color: #FFFFFF;
}

.article-full-body p {
  margin-bottom: 16px;
}

.article-full-body ul, .article-full-body ol {
  margin: 16px 0 16px 24px;
}

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

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

.review-card {
  padding: 28px;
}

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

.user-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--electric-blue-dark), var(--electric-blue));
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: #050C1A;
}

.user-name {
  font-weight: 700;
  color: #FFFFFF;
}

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

.rating-stars {
  color: var(--warning-amber);
  margin-bottom: 12px;
}

.review-text {
  font-size: 0.925rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* FAQ Accordion Section */
.faq-list {
  max-width: 840px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  border: 1px solid var(--border-hull);
  border-radius: 12px;
  overflow: hidden;
  background: var(--bg-hull-card);
}

.faq-question {
  width: 100%;
  padding: 20px 24px;
  background: none;
  border: none;
  color: #FFFFFF;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1.05rem;
  text-align: left;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  transition: color 0.2s;
}

.faq-question:hover {
  color: var(--electric-blue);
}

.faq-icon {
  font-size: 1.2rem;
  transition: transform 0.3s ease;
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s 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;
}

/* Footer & PBN Links (语义化 <footer>，符合需求 2) */
.site-footer {
  background: #030812;
  border-top: 1px solid rgba(0, 240, 255, 0.15);
  padding: 60px 0 30px;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-dim);
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 30px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.2rem;
  font-weight: 700;
  color: #FFFFFF;
}

.footer-nav {
  display: flex;
  gap: 24px;
  list-style: none;
  flex-wrap: wrap;
  justify-content: center;
}

.footer-nav a {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* PBN 权重输血友情链接区 (低调、美观、小字号、融合深海风) */
.pbn-links-zone {
  width: 100%;
  max-width: 1000px;
  margin: 20px auto 0;
  padding: 20px 24px;
  background: rgba(5, 12, 26, 0.5);
  border: 1px dashed rgba(0, 240, 255, 0.12);
  border-radius: 12px;
  text-align: center;
}

.pbn-title {
  font-size: 0.75rem;
  font-family: var(--font-mono);
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 12px;
}

.pbn-links-list {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px 18px;
  list-style: none;
  font-size: 0.775rem;
}

.pbn-links-list a {
  color: #64748B;
  transition: color 0.2s ease;
}

.pbn-links-list a:hover {
  color: var(--electric-blue);
  text-shadow: 0 0 6px rgba(0, 240, 255, 0.4);
}

.copyright-text {
  margin-top: 15px;
  font-size: 0.8rem;
  color: var(--text-dim);
}

/* Responsive Media Queries */
@media (max-width: 992px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 40px;
    text-align: center;
  }
  
  .hero-subtitle {
    margin-left: auto;
    margin-right: auto;
  }
  
  .hero-actions {
    justify-content: center;
  }
  
  .hero-stats {
    max-width: 500px;
    margin: 0 auto;
  }
  
  .hero-title {
    font-size: 2.5rem;
  }
}

@media (max-width: 768px) {
  .nav-menu {
    display: none;
    position: absolute;
    top: 80px;
    left: 0;
    width: 100%;
    background: var(--bg-depths);
    flex-direction: column;
    padding: 24px;
    border-bottom: 1px solid var(--border-hull);
  }
  
  .nav-menu.active {
    display: flex;
  }
  
  .mobile-toggle {
    display: block;
  }
  
  .hero-title {
    font-size: 2.1rem;
  }
  
  .section-title {
    font-size: 1.8rem;
  }
  
  .modal-content {
    padding: 24px;
  }
}