/* ==========================================================================
   TNTCloud Airport - Monochrome Modern Design System & Layout
   ========================================================================== */

/* Design Tokens & CSS Variables */
:root {
  --bg-dark: #08080a;
  --bg-card: rgba(18, 18, 22, 0.75);
  --bg-card-hover: rgba(28, 28, 35, 0.85);
  --bg-sidebar: #0b0b0e;
  --border-color: rgba(255, 255, 255, 0.08);
  --border-color-hover: rgba(255, 255, 255, 0.22);

  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --accent-white: #ffffff;
  --accent-glow: rgba(255, 255, 255, 0.15);

  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --sidebar-width: 270px;
  --header-height: 60px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;

  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

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

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

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

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

/* App Outer Shell: 2-Column Sidebar Layout */
.app-container {
  display: flex;
  min-height: 100vh;
  position: relative;
  z-index: 1;
}

/* ----------------------------------------------------
   Left Sidebar Navigation
---------------------------------------------------- */
.app-sidebar {
  width: var(--sidebar-width);
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border-color);
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  z-index: 100;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 1.5rem 1.25rem;
  transition: transform var(--transition-normal);
  backdrop-filter: blur(12px);
}

.sidebar-header {
  margin-bottom: 2rem;
}

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

.brand-logo .logo-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, #ffffff, #475569);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.2rem;
  color: #000;
  box-shadow: 0 0 15px rgba(255, 255, 255, 0.2);
}

.brand-logo .brand-text {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.5px;
}

.brand-logo .brand-badge {
  font-size: 0.65rem;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  color: var(--text-muted);
  font-weight: 500;
}

.sidebar-menu {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  flex: 1;
}

.sidebar-nav-title {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-dim);
  margin: 1.2rem 0 0.4rem 0.75rem;
  font-weight: 600;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.7rem 0.9rem;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  border: 1px solid transparent;
}

.nav-link i {
  font-size: 1.1rem;
  width: 20px;
  text-align: center;
  opacity: 0.7;
}

.nav-link:hover {
  color: var(--text-main);
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(255, 255, 255, 0.08);
}

.nav-link.active {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.15);
  font-weight: 600;
  box-shadow: inset 3px 0 0 #ffffff;
}

.sidebar-cta-box {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-color);
  padding: 1rem;
  border-radius: var(--radius-md);
  text-align: center;
}

.sidebar-cta-box p {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

/* Sidebar Overlay for Mobile */
.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(4px);
  z-index: 99;
}

.sidebar-overlay.active {
  display: block;
}

/* ----------------------------------------------------
   Right Main Content Area
---------------------------------------------------- */
.app-main {
  margin-left: var(--sidebar-width);
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

/* Top Announcement Header Bar */
.top-announcement {
  background: linear-gradient(90deg, #0f172a, #1e293b, #0f172a);
  border-bottom: 1px solid var(--border-color);
  padding: 0.6rem 1.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 90;
  backdrop-filter: blur(10px);
}

.announcement-content {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.announcement-tag {
  background: #ffffff;
  color: #000;
  font-weight: 700;
  font-size: 0.7rem;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  text-transform: uppercase;
}

.mobile-nav-bar {
  display: none;
  align-items: center;
  justify-content: space-between;
  padding: 0.8rem 1.25rem;
  background: var(--bg-sidebar);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 95;
}

.mobile-menu-btn {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
}

/* Page Section Wrappers */
.main-content-inner {
  padding: 2.5rem 3rem;
  max-width: 1280px;
  width: 100%;
  margin: 0 auto;
}

section {
  margin-bottom: 5rem;
  scroll-margin-top: 5rem;
}

.section-header {
  margin-bottom: 2.5rem;
  text-align: left;
}

.section-tag {
  display: inline-block;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--text-muted);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  padding: 0.25rem 0.75rem;
  border-radius: 50px;
  margin-bottom: 0.75rem;
  font-weight: 600;
}

.section-title {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  color: var(--text-main);
  margin-bottom: 0.5rem;
}

.section-desc {
  color: var(--text-muted);
  font-size: 1rem;
  max-width: 700px;
}

/* Common UI Elements */
.glass-panel {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(16px);
  transition: all var(--transition-normal);
}

.glass-panel:hover {
  border-color: var(--border-color-hover);
  background: var(--bg-card-hover);
}

.btn-primary {
  background: #ffffff;
  color: #000000;
  font-weight: 700;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-size: 0.95rem;
  transition: all var(--transition-fast);
  box-shadow: 0 0 20px rgba(255, 255, 255, 0.15);
}

.btn-primary:hover {
  background: #e2e8f0;
  transform: translateY(-2px);
  box-shadow: 0 0 30px rgba(255, 255, 255, 0.3);
}

.btn-outline {
  background: transparent;
  color: var(--text-main);
  font-weight: 600;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-size: 0.95rem;
  transition: all var(--transition-fast);
}

.btn-outline:hover {
  border-color: rgba(255, 255, 255, 0.4);
  background: rgba(255, 255, 255, 0.05);
}

.btn-sm {
  padding: 0.4rem 0.9rem;
  font-size: 0.8rem;
  border-radius: var(--radius-sm);
}

.full-width {
  width: 100%;
}

/* ----------------------------------------------------
   Hero Section
---------------------------------------------------- */
.hero-section {
  padding: 3rem 0 2rem 0;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 3rem;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
  padding: 0.35rem 0.9rem;
  border-radius: 50px;
  font-size: 0.8rem;
  color: var(--text-main);
  margin-bottom: 1.5rem;
}

.hero-title {
  font-size: 3.2rem;
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -1.5px;
  margin-bottom: 1.25rem;
  background: linear-gradient(180deg, #ffffff 0%, #94a3b8 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-sub {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
}

.hero-features-list {
  display: flex;
  gap: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
}

.feature-pill {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.feature-pill i {
  color: #ffffff;
}

/* Hero Right Visual Card */
.hero-visual-card {
  padding: 1.75rem;
  position: relative;
  overflow: hidden;
}

.visual-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
}

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

.dot-red, .dot-yellow, .dot-green {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
}

.visual-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.stat-item {
  background: rgba(0, 0, 0, 0.4);
  padding: 1rem;
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.stat-val {
  font-size: 1.75rem;
  font-weight: 800;
  color: #ffffff;
}

.stat-lbl {
  font-size: 0.75rem;
  color: var(--text-dim);
}

.protocol-tags {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.proto-tag {
  background: rgba(255, 255, 255, 0.08);
  font-size: 0.75rem;
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  color: var(--text-muted);
}

/* ----------------------------------------------------
   Node Latency & Status Monitor Section
---------------------------------------------------- */
.nodes-control-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  background: rgba(255, 255, 255, 0.02);
  padding: 1rem 1.5rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.nodes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.25rem;
}

.node-card {
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.node-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.node-title-box {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

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

.node-name {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-main);
}

.status-badge {
  font-size: 0.7rem;
  padding: 0.15rem 0.5rem;
  border-radius: 50px;
  background: rgba(34, 197, 94, 0.1);
  color: #4ade80;
  border: 1px solid rgba(34, 197, 94, 0.2);
  display: flex;
  align-items: center;
  gap: 0.3rem;
}

.status-badge .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #4ade80;
  box-shadow: 0 0 8px #4ade80;
}

.node-body {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.5rem;
  background: rgba(0, 0, 0, 0.3);
  padding: 0.75rem;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(255, 255, 255, 0.03);
}

.metric {
  display: flex;
  flex-direction: column;
}

.metric-label {
  font-size: 0.7rem;
  color: var(--text-dim);
}

.metric-val {
  font-size: 0.85rem;
  font-weight: 700;
}

.ping-low {
  color: #4ade80;
}

.ping-mid {
  color: #fbbf24;
}

.node-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
}

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

/* ----------------------------------------------------
   Core Advantages Section
---------------------------------------------------- */
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}

.advantage-card {
  padding: 2rem 1.5rem;
  text-align: left;
}

.adv-icon {
  width: 50px;
  height: 50px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 1.25rem;
  color: #ffffff;
}

.adv-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 0.6rem;
}

.adv-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* ----------------------------------------------------
   Pricing Plans Section
---------------------------------------------------- */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
  align-items: stretch;
}

.pricing-card {
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  position: relative;
}

.pricing-card.featured {
  border-color: rgba(255, 255, 255, 0.35);
  box-shadow: 0 0 30px rgba(255, 255, 255, 0.08);
}

.popular-badge {
  position: absolute;
  top: -12px;
  right: 20px;
  background: #ffffff;
  color: #000;
  font-size: 0.7rem;
  font-weight: 800;
  padding: 0.2rem 0.6rem;
  border-radius: 50px;
  text-transform: uppercase;
}

.plan-name {
  font-size: 1.3rem;
  font-weight: 800;
  margin-bottom: 0.4rem;
}

.plan-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.plan-price {
  font-size: 2.4rem;
  font-weight: 900;
  color: #ffffff;
  margin-bottom: 1.5rem;
}

.plan-price span {
  font-size: 0.9rem;
  color: var(--text-dim);
  font-weight: 400;
}

.plan-features {
  list-style: none;
  margin-bottom: 2rem;
  flex: 1;
}

.plan-features li {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.plan-features li i {
  color: #ffffff;
  font-size: 0.9rem;
}

/* ----------------------------------------------------
   Knowledge Base / Tutorials Section
---------------------------------------------------- */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 1.5rem;
}

.article-card {
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
  font-size: 0.75rem;
  color: var(--text-dim);
}

.article-tag {
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-main);
  padding: 0.15rem 0.5rem;
  border-radius: 4px;

}

.article-title {
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 0.75rem;
  color: var(--text-main);
}

.article-title a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast);
}

.article-title a:hover {
  color: #ffffff;
  text-decoration: underline;
}

.article-excerpt {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-link {
  font-size: 0.85rem;
  font-weight: 600;
  color: #ffffff;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.article-link:hover {
  text-decoration: underline;
}

/* ----------------------------------------------------
   FAQ Section
---------------------------------------------------- */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

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

.faq-question {
  padding: 1.25rem 1.5rem;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-main);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-toggle-icon {
  font-size: 1.2rem;
  transition: transform var(--transition-fast);
  color: var(--text-dim);
}

.faq-item.active .faq-toggle-icon {
  transform: rotate(45deg);
  color: #ffffff;
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  padding: 0 1.5rem;
  color: var(--text-muted);
  font-size: 0.92rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 400px;
  padding: 0 1.5rem 1.25rem 1.5rem;
}

/* ----------------------------------------------------
   User Reviews Section
---------------------------------------------------- */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}

.review-card {
  padding: 1.75rem;
}

.review-stars {
  color: #f59e0b;
  font-size: 0.9rem;
  margin-bottom: 1rem;
}

.review-text {
  font-size: 0.92rem;
  color: var(--text-muted);
  margin-bottom: 1.25rem;
  font-style: italic;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.author-avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: linear-gradient(135deg, #334155, #0f172a);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
  color: #ffffff;
}

.author-name {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-main);
}

.author-role {
  font-size: 0.75rem;
  color: var(--text-dim);
}

/* ----------------------------------------------------
   Footer
---------------------------------------------------- */
.app-footer {
  border-top: 1px solid var(--border-color);
  padding: 3rem 0;
  margin-top: 4rem;
  color: var(--text-dim);
  font-size: 0.85rem;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
}

.footer-links a {
  color: var(--text-muted);
  text-decoration: none;
}

.footer-links a:hover {
  color: #ffffff;
}

/* ----------------------------------------------------
   Article Detail View Base Layout (For standalone article pages)
---------------------------------------------------- */
.article-page-body {
  line-height: 1.8;
}

.article-content-container {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 3rem;
  margin-bottom: 3rem;
}

.article-header-meta {
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1.5rem;
  margin-bottom: 2rem;
}

.article-h1 {
  font-size: 2.2rem;
  font-weight: 900;
  line-height: 1.25;
  margin-bottom: 1rem;
}

.article-body-text h2 {
  font-size: 1.4rem;
  margin: 2rem 0 1rem 0;
  color: #ffffff;
  border-left: 3px solid #ffffff;
  padding-left: 0.75rem;
}

.article-body-text h3 {
  font-size: 1.15rem;
  margin: 1.5rem 0 0.75rem 0;
  color: var(--text-main);
}

.article-body-text p {
  margin-bottom: 1.25rem;
  color: var(--text-muted);
}

.article-body-text ul, .article-body-text ol {
  margin: 1rem 0 1.5rem 1.5rem;
  color: var(--text-muted);
}

.article-body-text li {
  margin-bottom: 0.5rem;
}

.article-callout {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  margin: 1.5rem 0;
}

/* ----------------------------------------------------
   Responsive Adjustments
---------------------------------------------------- */
@media (max-width: 992px) {
  .app-sidebar {
    transform: translateX(-100%);
  }

  .app-sidebar.open {
    transform: translateX(0);
  }

  .app-main {
    margin-left: 0;
  }

  .mobile-nav-bar {
    display: flex;
  }

  .top-announcement {
    display: none;
  }

  .hero-grid {
    grid-template-columns: 1fr;
  }

  .main-content-inner {
    padding: 1.5rem;
  }

  .hero-title {
    font-size: 2.4rem;
  }
}