/* ==========================================================================
   FlyingBird (飞鸟机场) - Skyline Azure & Solar Amber Aerodynamic System
   ========================================================================== */

:root {
  --color-bg-base: #070e1c;
  --color-bg-surface: #0c172d;
  --color-bg-surface-elevated: #122140;
  --color-bg-card: #0f1c36;

  --color-sky-blue: #38bdf8;
  --color-azure: #0284c7;
  --color-amber: #f59e0b;
  --color-amber-bright: #fbbf24;

  --color-border: rgba(56, 189, 248, 0.2);
  --color-border-subtle: rgba(255, 255, 255, 0.08);
  --color-border-hover: rgba(245, 158, 11, 0.5);

  --color-text-primary: #f8fafc;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;

  --color-success: #10b981;

  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "SF Mono", Monaco, Consolas, monospace;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-full: 9999px;

  --shadow-sky: 0 10px 30px -5px rgba(2, 132, 199, 0.3);
  --shadow-amber: 0 10px 30px -5px rgba(245, 158, 11, 0.3);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--color-bg-base);
  color: var(--color-text-primary);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
}

body {
  background-color: var(--color-bg-base);
  color: var(--color-text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
}

/* Aerodynamic Sky Atmosphere */
.bg-skyline {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background: 
    radial-gradient(circle at 50% 0%, rgba(2, 132, 199, 0.15) 0%, transparent 60%),
    radial-gradient(circle at 85% 30%, rgba(245, 158, 11, 0.08) 0%, transparent 50%),
    radial-gradient(circle at 15% 70%, rgba(56, 189, 248, 0.08) 0%, transparent 50%);
}

.container {
  width: 100%;
  max-width: 1220px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.25rem;
  padding-right: 1.25rem;
  position: relative;
  z-index: 1;
}

/* Gradient Text */
.sky-gradient-text {
  background: linear-gradient(135deg, #ffffff 0%, var(--color-sky-blue) 45%, var(--color-amber-bright) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 0.95rem;
  padding: 0.75rem 1.6rem;
  border-radius: var(--radius-full);
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 200ms ease;
  white-space: nowrap;
}

.btn-sky {
  background: linear-gradient(135deg, #0284c7 0%, #38bdf8 60%, #f59e0b 100%);
  color: #ffffff;
  box-shadow: var(--shadow-sky);
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.btn-sky:hover {
  transform: translateY(-2px);
  filter: brightness(1.08);
  box-shadow: 0 14px 35px -5px rgba(2, 132, 199, 0.45);
}

.btn-outline {
  background: rgba(18, 33, 64, 0.6);
  backdrop-filter: blur(12px);
  color: #ffffff;
  border: 1px solid var(--color-border);
}

.btn-outline:hover {
  background: var(--color-bg-surface-elevated);
  border-color: var(--color-sky-blue);
  color: var(--color-sky-blue);
  transform: translateY(-2px);
}

.btn-sm {
  padding: 0.45rem 1.1rem;
  font-size: 0.875rem;
}

.btn-lg {
  padding: 0.9rem 2.2rem;
  font-size: 1.05rem;
}

/* Header */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(7, 14, 28, 0.82);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-border-subtle);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.brand-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--color-text-primary);
}

.brand-icon-wrap {
  width: 42px;
  height: 42px;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--color-border);
  box-shadow: 0 0 16px rgba(2, 132, 199, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg-surface);
}

.brand-icon {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.brand-name {
  font-weight: 800;
  font-size: 1.25rem;
  letter-spacing: 0.01em;
}

.brand-badge {
  font-size: 0.6875rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  background: rgba(245, 158, 11, 0.15);
  color: var(--color-amber-bright);
  border: 1px solid rgba(245, 158, 11, 0.3);
  margin-left: 0.4rem;
}

.brand-sub {
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

.nav-desktop {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-link {
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: 0.9375rem;
  font-weight: 600;
  transition: color 150ms ease;
}

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.mobile-menu-btn {
  display: none;
  background: transparent;
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  color: #fff;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

/* Hero Section */
.hero-section {
  padding-top: 4.5rem;
  padding-bottom: 5.5rem;
  text-align: center;
  position: relative;
}

.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1.2rem;
  border-radius: var(--radius-full);
  background: rgba(2, 132, 199, 0.12);
  border: 1px solid var(--color-border);
  color: var(--color-sky-blue);
  font-size: 0.85rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
}

.hero-pill-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-amber);
  box-shadow: 0 0 10px var(--color-amber);
  animation: pulse-dot 1.8s infinite;
}

@keyframes pulse-dot {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(0.8); opacity: 0.5; }
}

.hero-title {
  font-size: clamp(2.3rem, 5vw, 4.3rem);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: -0.025em;
  max-width: 920px;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 1.25rem;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--color-text-secondary);
  max-width: 740px;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 2.5rem;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 3.5rem;
}

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  max-width: 980px;
  margin-left: auto;
  margin-right: auto;
  background: rgba(12, 23, 45, 0.7);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem 1rem;
  backdrop-filter: blur(12px);
}

.metric-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  border-right: 1px solid var(--color-border-subtle);
}

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

.metric-val {
  font-size: 1.75rem;
  font-weight: 900;
  font-family: var(--font-mono);
  color: var(--color-sky-blue);
}

.metric-label {
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  font-weight: 600;
}

/* Sections */
.section {
  padding-top: 4.5rem;
  padding-bottom: 4.5rem;
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 3.5rem;
}

.section-tag {
  font-size: 0.8125rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-amber);
  margin-bottom: 0.5rem;
  display: inline-block;
}

.section-title {
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  font-weight: 900;
  margin-bottom: 1rem;
}

.section-desc {
  font-size: 1rem;
  color: var(--color-text-secondary);
  line-height: 1.65;
}

/* Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.feature-card {
  background: var(--color-bg-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  transition: all 250ms ease;
  position: relative;
  overflow: hidden;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: var(--color-amber);
  box-shadow: 0 12px 30px rgba(2, 132, 199, 0.25);
}

.feature-icon-box {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, rgba(2, 132, 199, 0.2), rgba(245, 158, 11, 0.2));
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-sky-blue);
  margin-bottom: 1.25rem;
  font-size: 1.5rem;
}

.feature-card-title {
  font-size: 1.2rem;
  font-weight: 800;
  margin-bottom: 0.75rem;
  color: #fff;
}

.feature-card-desc {
  font-size: 0.925rem;
  color: var(--color-text-secondary);
  line-height: 1.65;
}

/* Nodes Grid */
.nodes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
  gap: 1rem;
}

.node-card {
  background: var(--color-bg-surface);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: all 150ms ease;
}

.node-card:hover {
  border-color: var(--color-border);
  background: var(--color-bg-surface-elevated);
}

.node-info-left {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.node-flag {
  font-size: 1.5rem;
}

.node-name {
  font-weight: 700;
  font-size: 0.95rem;
}

.node-type {
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

.node-status-right {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 2px;
}

.node-ping {
  font-family: var(--font-mono);
  font-size: 0.825rem;
  font-weight: 700;
  color: var(--color-success);
}

.node-badge {
  font-size: 0.6875rem;
  background: rgba(2, 132, 199, 0.15);
  color: var(--color-sky-blue);
  padding: 1px 6px;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(2, 132, 199, 0.3);
}

/* Pricing Grid */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
  align-items: stretch;
}

.pricing-card {
  background: var(--color-bg-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all 250ms ease;
}

.pricing-card.popular {
  border-color: var(--color-amber);
  background: linear-gradient(180deg, #152747 0%, #0c172d 100%);
  box-shadow: 0 16px 40px -10px rgba(245, 158, 11, 0.25);
  transform: scale(1.03);
}

.badge-popular {
  position: absolute;
  top: -13px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(135deg, #0284c7 0%, #f59e0b 100%);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 800;
  padding: 3px 12px;
  border-radius: var(--radius-full);
}

.pricing-plan-name {
  font-size: 1.3rem;
  font-weight: 800;
  margin-bottom: 0.25rem;
}

.pricing-plan-desc {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  margin-bottom: 1.25rem;
  min-height: 40px;
}

.pricing-price-box {
  display: flex;
  align-items: baseline;
  gap: 2px;
  margin-bottom: 1.5rem;
}

.price-currency {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--color-sky-blue);
}

.price-number {
  font-size: 2.8rem;
  font-weight: 900;
  font-family: var(--font-mono);
  color: #fff;
  line-height: 1;
}

.price-period {
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.pricing-features-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-bottom: 2rem;
  flex-grow: 1;
}

.feature-line {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

.feature-check {
  color: var(--color-sky-blue);
  font-weight: 800;
}

/* FAQ */
.faq-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.faq-card {
  background: var(--color-bg-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
}

.faq-question {
  font-size: 1.05rem;
  font-weight: 800;
  color: #fff;
  margin-bottom: 0.75rem;
}

.faq-answer {
  font-size: 0.925rem;
  color: var(--color-text-secondary);
  line-height: 1.65;
}

/* Footer */
.footer {
  border-top: 1px solid var(--color-border-subtle);
  background: #050a14;
  padding-top: 3.5rem;
  padding-bottom: 2.5rem;
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.footer-top {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 2rem;
  margin-bottom: 2.5rem;
}

.footer-bottom {
  border-top: 1px solid var(--color-border-subtle);
  padding-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

/* Responsive */
@media (max-width: 1024px) {
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-desktop {
    display: none;
  }
  .mobile-menu-btn {
    display: inline-flex;
  }
  .hero-metrics {
    grid-template-columns: repeat(2, 1fr);
  }
  .features-grid, .pricing-grid, .faq-grid {
    grid-template-columns: 1fr;
  }
  .pricing-card.popular {
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}