/* ==========================================================================
   NEXITALLY Airport Landing Page - Black & White Theme System
   Layout: 3-Column Modern Grid (Left Nav | Center Main | Right Sidebar)
   ========================================================================== */

:root {
  --bg-dark: #09090b;
  --bg-surface: #121216;
  --bg-card: #18181c;
  --bg-card-hover: #222228;
  --border-color: #27272a;
  --border-highlight: #3f3f46;
  
  --text-primary: #ffffff;
  --text-secondary: #a1a1aa;
  --text-muted: #71717a;
  
  --accent-white: #ffffff;
  --accent-silver: #e4e4e7;
  --accent-subtle: #27272a;
  
  --status-green: #10b981;
  --status-yellow: #f59e0b;
  --status-blue: #3b82f6;

  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;

  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 30px rgba(255, 255, 255, 0.06);
}

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

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

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

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

/* Top Announcement Banner (Slogan & Features) */
.top-slogan-bar {
  background: linear-gradient(90deg, #09090b 0%, #1f1f23 50%, #09090b 100%);
  border-bottom: 1px solid var(--border-color);
  padding: 10px 16px;
  text-align: center;
  font-size: 0.88rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  position: relative;
  z-index: 100;
}

.top-slogan-bar strong {
  color: var(--accent-white);
  background: #27272a;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.top-slogan-bar a.slogan-link {
  color: var(--accent-white);
  text-decoration: underline;
  cursor: pointer;
  font-weight: 600;
}

/* Header & Top Bar Navigation */
.top-header {
  position: sticky;
  top: 0;
  z-index: 99;
  background: rgba(9, 9, 11, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  padding: 12px 24px;
}

.top-nav-container {
  max-width: 1440px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo-wrap {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-primary);
}

.brand-logo-img {
  height: 38px;
  width: auto;
}

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

.top-nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 500;
  transition: color var(--transition-fast);
}

.top-nav-links a:hover {
  color: var(--text-primary);
}

.header-cta-btn {
  background: var(--accent-white);
  color: #000000;
  border: none;
  padding: 8px 18px;
  border-radius: var(--radius-md);
  font-weight: 700;
  font-size: 0.88rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  box-shadow: 0 0 15px rgba(255, 255, 255, 0.15);
}

.header-cta-btn:hover {
  background: #e4e4e7;
  transform: translateY(-1px);
}

/* Three Column App Layout Wrapper */
.app-container {
  max-width: 1440px;
  margin: 0 auto;
  padding: 24px 16px;
  display: grid;
  grid-template-columns: 240px 1fr 280px;
  gap: 24px;
  align-items: start;
}

/* ==========================================================================
   Column 1: Left Navigation Sidebar
   ========================================================================== */
.left-sidebar {
  position: sticky;
  top: 80px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.sidebar-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 18px;
  box-shadow: var(--shadow-sm);
}

.sidebar-menu-title {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  margin-bottom: 12px;
  font-weight: 700;
}

.sidebar-nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.sidebar-nav-list a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  transition: all var(--transition-fast);
}

.sidebar-nav-list a:hover,
.sidebar-nav-list a.active {
  background: var(--bg-card);
  color: var(--accent-white);
  border-left: 3px solid var(--accent-white);
}

.sidebar-nav-list svg {
  width: 18px;
  height: 18px;
  stroke: currentColor;
}

.sidebar-status-widget {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px;
}

.status-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
  font-size: 0.85rem;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--status-green);
  box-shadow: 0 0 8px var(--status-green);
}

.sidebar-cta {
  width: 100%;
  background: linear-gradient(135deg, #ffffff 0%, #a1a1aa 100%);
  color: #000000;
  border: none;
  padding: 12px;
  border-radius: var(--radius-md);
  font-weight: 800;
  font-size: 0.95rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all var(--transition-fast);
}

.sidebar-cta:hover {
  opacity: 0.9;
  transform: translateY(-2px);
}

/* ==========================================================================
   Column 2: Center Main Content
   ========================================================================== */
.main-content {
  display: flex;
  flex-direction: column;
  gap: 40px;
}

/* Hero Banner Section */
.hero-section {
  background: linear-gradient(180deg, rgba(24, 24, 28, 0.8) 0%, rgba(18, 18, 22, 0.4) 100%);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 40px 32px;
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-glow);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--border-highlight);
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 0.82rem;
  color: var(--accent-white);
  margin-bottom: 20px;
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 900;
  line-height: 1.2;
  margin-bottom: 16px;
  background: linear-gradient(180deg, #ffffff 0%, #a1a1aa 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto 28px;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn-primary {
  background: var(--accent-white);
  color: #000000;
  border: none;
  padding: 14px 32px;
  border-radius: var(--radius-md);
  font-weight: 800;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  box-shadow: 0 4px 20px rgba(255, 255, 255, 0.2);
}

.btn-primary:hover {
  background: #e4e4e7;
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(255, 255, 255, 0.3);
}

.btn-secondary {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-highlight);
  padding: 14px 28px;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn-secondary:hover {
  background: var(--bg-card);
  border-color: var(--text-secondary);
}

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 36px;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
}

.metric-item {
  text-align: center;
}

.metric-num {
  font-size: 1.4rem;
  font-weight: 900;
  color: var(--accent-white);
}

.metric-label {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* Section Header Shared Component */
.section-header {
  margin-bottom: 24px;
}

.section-tag {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--text-muted);
  font-weight: 700;
}

.section-title {
  font-size: 1.65rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-top: 4px;
}

/* Section 3: Node Latency & Status Monitor */
.node-status-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
}

.node-controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
  flex-wrap: wrap;
  gap: 12px;
}

.node-filters {
  display: flex;
  gap: 8px;
}

.filter-chip {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 5px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-chip.active,
.filter-chip:hover {
  background: var(--accent-white);
  color: #000000;
  font-weight: 700;
}

.ping-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-highlight);
  color: var(--text-primary);
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
}

.node-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 14px;
}

.node-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: border-color var(--transition-fast);
}

.node-item:hover {
  border-color: var(--border-highlight);
}

.node-flag {
  font-size: 1.2rem;
}

.node-info {
  display: flex;
  flex-direction: column;
}

.node-name {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--text-primary);
}

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

.node-latency {
  font-family: monospace;
  font-size: 0.85rem;
  font-weight: 700;
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  background: rgba(16, 185, 129, 0.1);
  color: var(--status-green);
  border: 1px solid rgba(16, 185, 129, 0.2);
}

/* Section 4: Pricing Plans */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.pricing-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all var(--transition-smooth);
}

.pricing-card.featured {
  border-color: var(--accent-white);
  box-shadow: 0 0 25px rgba(255, 255, 255, 0.08);
  transform: translateY(-4px);
}

.featured-badge {
  position: absolute;
  top: -12px;
  right: 20px;
  background: var(--accent-white);
  color: #000000;
  font-size: 0.72rem;
  font-weight: 800;
  padding: 3px 10px;
  border-radius: 12px;
  text-transform: uppercase;
}

.plan-name {
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 6px;
}

.plan-desc {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: 18px;
}

.plan-price {
  font-size: 2.2rem;
  font-weight: 900;
  color: var(--accent-white);
  margin-bottom: 20px;
}

.plan-price span {
  font-size: 0.85rem;
  font-weight: 400;
  color: var(--text-muted);
}

.plan-features {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 24px;
  flex-grow: 1;
}

.plan-features li {
  font-size: 0.88rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.plan-features svg {
  width: 16px;
  height: 16px;
  stroke: var(--accent-white);
  flex-shrink: 0;
}

.plan-btn {
  width: 100%;
  padding: 12px;
  border-radius: var(--radius-md);
  font-weight: 700;
  font-size: 0.92rem;
  cursor: pointer;
  border: 1px solid var(--border-highlight);
  background: var(--bg-card);
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.pricing-card.featured .plan-btn {
  background: var(--accent-white);
  color: #000000;
  border: none;
}

.plan-btn:hover {
  background: var(--accent-silver);
  color: #000000;
}

/* Core Advantages Section */
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.advantage-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 20px;
  transition: border-color var(--transition-fast);
}

.advantage-card:hover {
  border-color: var(--border-highlight);
}

.advantage-icon {
  width: 42px;
  height: 42px;
  border-radius: var(--radius-md);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 14px;
}

.advantage-icon svg {
  width: 22px;
  height: 22px;
  stroke: var(--accent-white);
}

.advantage-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.advantage-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* Section 5: FAQ & Knowledge Base Articles */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 36px;
}

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

.faq-question {
  width: 100%;
  padding: 16px 20px;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 0.98rem;
  font-weight: 700;
  text-align: left;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
}

.faq-answer {
  padding: 0 20px 16px 20px;
  color: var(--text-secondary);
  font-size: 0.88rem;
  display: none;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 12px;
}

.faq-item.open .faq-answer {
  display: block;
}

.faq-item.open .faq-question svg {
  transform: rotate(180deg);
}

/* Knowledge Base Article Section */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.article-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 22px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all var(--transition-fast);
  cursor: pointer;
}

.article-card:hover {
  border-color: var(--accent-white);
  transform: translateY(-2px);
}

.article-tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent-silver);
  background: var(--bg-card);
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  margin-bottom: 10px;
  width: fit-content;
}

.article-title {
  font-size: 1.1rem;
  font-weight: 800;
  line-height: 1.4;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.article-excerpt {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.78rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-color);
  padding-top: 12px;
}

/* Section 6: Testimonials */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.testimonial-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 20px;
}

.testimonial-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: #27272a;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: var(--accent-white);
  border: 1px solid var(--border-highlight);
}

.user-info h4 {
  font-size: 0.9rem;
  font-weight: 700;
}

.user-info span {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.stars {
  color: #f59e0b;
  font-size: 0.8rem;
  margin-bottom: 8px;
}

.testimonial-text {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-style: italic;
}

/* ==========================================================================
   Column 3: Right Sidebar (Recommendations & Tags)
   ========================================================================== */
.right-sidebar {
  position: sticky;
  top: 80px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.widget-title {
  font-size: 0.88rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.tags-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.tag-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 4px 10px;
  border-radius: 14px;
  font-size: 0.78rem;
  text-decoration: none;
  transition: all var(--transition-fast);
  cursor: pointer;
}

.tag-btn:hover {
  background: var(--accent-white);
  color: #000000;
  border-color: var(--accent-white);
}

.recommended-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.recommended-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 10px;
  background: var(--bg-card);
  border-radius: var(--radius-sm);
  font-size: 0.82rem;
}

.recommended-item .node-badge {
  background: rgba(16, 185, 129, 0.15);
  color: var(--status-green);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.72rem;
  font-weight: 700;
}

/* Article Reading Drawer / Modal */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.85);
  backdrop-filter: blur(8px);
  z-index: 1000;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal-overlay.active {
  display: flex;
}

.article-modal-container {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  max-width: 900px;
  width: 100%;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.8);
}

.modal-header {
  padding: 20px 28px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-card);
}

.modal-close-btn {
  background: none;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 36px;
  height: 36px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  transition: all var(--transition-fast);
}

.modal-close-btn:hover {
  background: var(--accent-white);
  color: #000000;
}

.modal-body {
  padding: 32px;
  overflow-y: auto;
  line-height: 1.8;
  color: var(--text-secondary);
}

.modal-body h1, .modal-body h2, .modal-body h3 {
  color: var(--text-primary);
  margin: 24px 0 12px;
}

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

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

.modal-body code {
  background: var(--bg-card);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: monospace;
  color: var(--accent-silver);
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border-color);
  background: var(--bg-surface);
  padding: 36px 20px;
  margin-top: 60px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* Responsive Media Queries */
@media (max-width: 1200px) {
  .app-container {
    grid-template-columns: 200px 1fr;
  }
  .right-sidebar {
    display: none;
  }
}

@media (max-width: 860px) {
  .app-container {
    grid-template-columns: 1fr;
  }
  .left-sidebar {
    display: none;
  }
  .top-nav-links {
    display: none;
  }
  .hero-title {
    font-size: 1.8rem;
  }
  .pricing-grid,
  .advantages-grid,
  .articles-grid,
  .testimonials-grid {
    grid-template-columns: 1fr;
  }
  .hero-metrics {
    grid-template-columns: repeat(2, 1fr);
  }
}