/* ==========================================================================
   FlyBitVPN - Cyber Aurora & Electric Indigo Edition
   Ultra-High Performance, Native CSS, Distinct Futuristic Cyber Security Aesthetic
   ========================================================================== */

:root {
  --bg-dark: #060813;
  --bg-surface: rgba(15, 23, 42, 0.78);
  --bg-surface-hover: rgba(30, 41, 59, 0.9);
  --bg-card: rgba(12, 18, 34, 0.72);

  --border-light: rgba(255, 255, 255, 0.08);
  --border-cyan: rgba(6, 182, 212, 0.3);
  --border-cyan-glow: rgba(34, 211, 238, 0.65);

  --accent-cyan: #06b6d4;
  --accent-blue: #3b82f6;
  --accent-indigo: #6366f1;
  --accent-violet: #8b5cf6;
  --accent-gradient: linear-gradient(135deg, #06b6d4 0%, #3b82f6 50%, #8b5cf6 100%);
  --btn-glow: 0 4px 25px rgba(6, 182, 212, 0.42);

  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-pill: 9999px;

  --transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background-color: var(--bg-dark);
  color: var(--text-main);
  line-height: 1.6;
}

body {
  overflow-x: hidden;
  position: relative;
  min-height: 100vh;
  background: 
    radial-gradient(circle at 15% 18%, rgba(6, 182, 212, 0.12) 0%, transparent 45%),
    radial-gradient(circle at 85% 22%, rgba(139, 92, 246, 0.12) 0%, transparent 45%),
    radial-gradient(circle at 50% 80%, rgba(59, 130, 246, 0.08) 0%, transparent 55%),
    var(--bg-dark);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Aurora Background Ambient Glow */
.aurora-bg {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 1050px;
  height: 520px;
  background: radial-gradient(ellipse at top, rgba(6, 182, 212, 0.24) 0%, rgba(99, 102, 241, 0.14) 45%, transparent 72%);
  filter: blur(95px);
  pointer-events: none;
  z-index: 0;
}

/* Navbar */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(6, 8, 19, 0.85);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border-light);
  height: 72px;
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: #fff;
  text-decoration: none;
}

.brand-icon {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: var(--accent-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 14px rgba(6, 182, 212, 0.45);
}

.brand-icon svg {
  width: 22px;
  height: 22px;
  fill: none;
  stroke: #fff;
  stroke-width: 2;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

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

.nav-link:hover {
  color: var(--accent-cyan);
}

.nav-link.highlight-tag {
  color: #22d3ee;
  position: relative;
}

.nav-link.highlight-tag::after {
  content: "HOT";
  font-size: 0.65rem;
  background: rgba(6, 182, 212, 0.2);
  color: #22d3ee;
  padding: 1px 5px;
  border-radius: 4px;
  margin-left: 6px;
  vertical-align: middle;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 22px;
  border-radius: var(--radius-pill);
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  transition: var(--transition);
}

.btn-primary {
  background: var(--accent-gradient);
  color: #ffffff;
  font-weight: 700;
  box-shadow: var(--btn-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 32px rgba(6, 182, 212, 0.6);
  color: #fff;
}

.btn-ghost {
  background: rgba(255, 255, 255, 0.04);
  color: var(--text-muted);
  border-color: var(--border-light);
}

.btn-ghost:hover {
  color: #fff;
  border-color: var(--border-cyan);
  background: rgba(6, 182, 212, 0.08);
}

.btn-lg {
  padding: 15px 38px;
  font-size: 1.1rem;
}

.btn-block {
  width: 100%;
}

.menu-toggle {
  display: none;
  background: transparent;
  border: none;
  cursor: pointer;
  flex-direction: column;
  gap: 5px;
  padding: 6px;
}

.menu-toggle span {
  width: 22px;
  height: 2px;
  background: #fff;
  border-radius: 2px;
}

/* Hero Section */
.hero-section {
  position: relative;
  padding: 150px 0 90px;
  text-align: center;
  z-index: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 18px;
  border-radius: var(--radius-pill);
  background: rgba(6, 182, 212, 0.12);
  border: 1px solid var(--border-cyan);
  font-size: 0.88rem;
  font-weight: 600;
  color: #a5f3fc;
  margin-bottom: 24px;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent-cyan);
  box-shadow: 0 0 10px var(--accent-cyan);
  animation: pulseDot 2s infinite;
}

@keyframes pulseDot {
  0% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(6, 182, 212, 0.7); }
  70% { transform: scale(1); box-shadow: 0 0 0 8px rgba(6, 182, 212, 0); }
  100% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(6, 182, 212, 0); }
}

.hero-title {
  font-size: 3.4rem;
  font-weight: 900;
  line-height: 1.22;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
}

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

.hero-subtitle {
  font-size: 1.2rem;
  color: var(--text-muted);
  max-width: 840px;
  margin: 0 auto 36px;
  line-height: 1.7;
}

.hero-cta-group {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-bottom: 50px;
}

/* Hero Metrics */
.hero-metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  background: var(--bg-surface);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-cyan);
  border-radius: var(--radius-lg);
  padding: 24px;
  max-width: 960px;
  margin: 0 auto;
}

.metric-item {
  text-align: center;
  border-right: 1px solid var(--border-light);
}

.metric-item:last-child {
  border-right: none;
}

.metric-val {
  font-size: 2rem;
  font-weight: 800;
  color: #fff;
  letter-spacing: -0.02em;
}

.metric-lbl {
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-top: 4px;
}

/* Sections */
.section {
  padding: 90px 0;
  position: relative;
  z-index: 1;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 60px;
}

.section-tag {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent-cyan);
  margin-bottom: 12px;
}

.section-title {
  font-size: 2.3rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 14px;
  color: #fff;
}

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

/* Cards Grid */
.cards-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.solar-card {
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 36px 30px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.solar-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--accent-gradient);
  opacity: 0;
  transition: var(--transition);
}

.solar-card:hover {
  transform: translateY(-6px);
  background: var(--bg-surface-hover);
  border-color: var(--border-cyan-glow);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.5);
}

.solar-card:hover::before {
  opacity: 1;
}

.card-icon-box {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: rgba(6, 182, 212, 0.14);
  border: 1px solid var(--border-cyan);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 22px;
}

.card-icon-box svg {
  width: 26px;
  height: 26px;
  fill: var(--accent-cyan);
}

.solar-card h3 {
  font-size: 1.3rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 12px;
}

.solar-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.65;
}

/* Matrix Section */
.matrix-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-top: 36px;
}

.matrix-item {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 20px;
  text-align: center;
  transition: var(--transition);
}

.matrix-item:hover {
  border-color: var(--accent-cyan);
  transform: translateY(-3px);
  background: rgba(6, 182, 212, 0.08);
}

.matrix-logo {
  font-size: 2rem;
  margin-bottom: 8px;
}

.matrix-title {
  font-weight: 700;
  font-size: 1rem;
  color: #fff;
}

.matrix-status {
  font-size: 0.78rem;
  color: var(--accent-cyan);
  margin-top: 4px;
}

/* Pricing Grid */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  transition: var(--transition);
}

.pricing-card.featured {
  border-color: var(--accent-cyan);
  background: rgba(15, 23, 42, 0.9);
  box-shadow: 0 10px 40px rgba(6, 182, 212, 0.22);
  transform: scale(1.03);
}

.pricing-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent-gradient);
  color: #ffffff;
  font-size: 0.8rem;
  font-weight: 800;
  padding: 4px 16px;
  border-radius: var(--radius-pill);
  box-shadow: 0 4px 12px rgba(6, 182, 212, 0.4);
}

.pricing-name {
  font-size: 1.25rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 8px;
}

.pricing-price {
  font-size: 2.8rem;
  font-weight: 900;
  color: #fff;
  margin-bottom: 16px;
}

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

.pricing-features {
  list-style: none;
  margin: 24px 0 32px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.pricing-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.95rem;
  color: var(--text-muted);
}

.pricing-features svg {
  width: 18px;
  height: 18px;
  fill: var(--accent-cyan);
  flex-shrink: 0;
}

/* FAQ Accordion */
.faq-list {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

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

.faq-item:hover {
  border-color: var(--border-cyan);
}

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

.faq-summary::-webkit-details-marker {
  display: none;
}

.faq-icon {
  width: 20px;
  height: 20px;
  fill: var(--text-dim);
  transition: var(--transition);
}

details[open] .faq-icon {
  transform: rotate(180deg);
  fill: var(--accent-cyan);
}

.faq-content {
  padding: 0 24px 22px;
  color: var(--text-muted);
  font-size: 0.96rem;
  line-height: 1.7;
}

/* CTA Banner */
.cta-banner {
  background: linear-gradient(135deg, rgba(6, 182, 212, 0.16) 0%, rgba(99, 102, 241, 0.12) 100%);
  border: 1px solid var(--border-cyan);
  border-radius: var(--radius-lg);
  padding: 60px 40px;
  text-align: center;
  margin-top: 80px;
  position: relative;
  overflow: hidden;
}

.cta-banner h2 {
  font-size: 2.2rem;
  font-weight: 800;
  color: #fff;
  margin-bottom: 16px;
}

.cta-banner p {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 680px;
  margin: 0 auto 32px;
}

/* Footer */
.footer, .site-footer {
  background: #04050a;
  border-top: 1px solid var(--border-light);
  padding: 50px 0 30px;
  margin-top: 90px;
  text-align: center;
}

.footer-nav {
  display: flex;
  justify-content: center;
  gap: 32px;
  margin-bottom: 24px;
}

.footer-link {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  transition: var(--transition);
}

.footer-link:hover {
  color: var(--accent-cyan);
}

.footer-copy {
  color: var(--text-dim);
  font-size: 0.85rem;
}

/* Responsive */
@media (max-width: 992px) {
  .hero-title { font-size: 2.6rem; }
  .cards-grid-3, .pricing-grid { grid-template-columns: 1fr; }
  .pricing-card.featured { transform: none; }
  .hero-metrics { grid-template-columns: repeat(2, 1fr); gap: 16px; }
  .metric-item { border-right: none; }
  .nav-links { display: none; }
  .menu-toggle { display: flex; }
  .nav-links.show {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--bg-dark);
    padding: 24px;
    border-bottom: 1px solid var(--border-light);
    gap: 16px;
  }
}

@media (max-width: 576px) {
  .hero-title { font-size: 2.1rem; }
  .hero-subtitle { font-size: 1rem; }
  .hero-metrics { grid-template-columns: 1fr; }
  .nav-actions .btn-ghost { display: none; }
  .footer-nav { flex-wrap: wrap; gap: 16px; }
}