/* Mekong Tech — Airtable Marketing Design System */

:root {
  --color-primary: #181d26;
  --color-primary-active: #0d1218;
  --color-canvas: #ffffff;
  --color-surface-soft: #f8fafc;
  --color-surface-strong: #e0e2e6;
  --color-surface-dark: #181d26;
  --color-surface-dark-elevated: #1d1f25;
  --color-hairline: #dddddd;
  --color-ink: #181d26;
  --color-body: #333840;
  --color-muted: #41454d;
  --color-border-strong: #9297a0;
  --color-on-primary: #ffffff;
  --color-signature-coral: #aa2d00;
  --color-signature-forest: #0a2e0e;
  --color-signature-cream: #f5e9d4;
  --color-signature-peach: #fcab79;
  --color-signature-mint: #a8d8c4;
  --color-signature-yellow: #f4d35e;
  --color-signature-mustard: #d9a441;
  --color-link: #1b61c9;
  --color-link-active: #1a3866;
  --color-info-border: #458fff;

  --rounded-xs: 2px;
  --rounded-sm: 6px;
  --rounded-md: 10px;
  --rounded-lg: 12px;
  --rounded-full: 9999px;

  --spacing-xxs: 4px;
  --spacing-xs: 8px;
  --spacing-sm: 12px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-xxl: 48px;
  --spacing-section: 96px;

  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --max-width: 1280px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 400;
  line-height: 1.25;
  color: var(--color-body);
  background: var(--color-canvas);
  -webkit-font-smoothing: antialiased;
}

img { display: block; max-width: 100%; height: auto; }

a { color: var(--color-link); text-decoration: none; }
a:active { color: var(--color-link-active); }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-xxl);
}

/* Typography */
.display-lg {
  font-size: 40px;
  font-weight: 400;
  line-height: 1.2;
  color: var(--color-ink);
  letter-spacing: 0;
}

.display-md {
  font-size: 32px;
  font-weight: 400;
  line-height: 1.2;
  color: var(--color-ink);
}

.title-lg {
  font-size: 24px;
  font-weight: 400;
  line-height: 1.35;
  letter-spacing: 0.12px;
  color: var(--color-ink);
}

.title-md {
  font-size: 20px;
  font-weight: 400;
  line-height: 1.5;
  color: var(--color-ink);
}

.title-sm {
  font-size: 18px;
  font-weight: 500;
  line-height: 1.4;
  color: var(--color-ink);
}

.label-md {
  font-size: 16px;
  font-weight: 500;
  line-height: 1.4;
  color: var(--color-ink);
}

.body-md { font-size: 14px; font-weight: 400; line-height: 1.25; }
.caption { font-size: 14px; font-weight: 500; line-height: 1.35; letter-spacing: 0.16px; color: var(--color-muted); }

.section-label {
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-muted);
  margin-bottom: var(--spacing-md);
}

/* Top Nav */
.top-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: 64px;
  background: var(--color-canvas);
  border-bottom: 1px solid transparent;
}

.top-nav.scrolled { border-bottom-color: var(--color-hairline); }

.top-nav .container {
  display: flex;
  align-items: center;
  height: 100%;
  gap: var(--spacing-lg);
}

.wordmark {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 16px;
  font-weight: 500;
  color: var(--color-ink);
  white-space: nowrap;
  flex-shrink: 0;
}

.brand-logo {
  width: 36px;
  height: 36px;
  border-radius: var(--rounded-sm);
  object-fit: cover;
  flex-shrink: 0;
  background: #1a1a1a;
}

.brand-name { color: var(--color-ink); }

.brand-name span { color: var(--color-muted); font-weight: 400; }

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  list-style: none;
  flex: 1;
}

.nav-menu a {
  font-size: 14px;
  color: var(--color-body);
  white-space: nowrap;
}

.nav-menu a:active,
.nav-menu a.active {
  color: var(--color-ink);
  font-weight: 500;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  flex-shrink: 0;
}

.top-nav .lang-switch {
  margin-left: var(--spacing-xs);
  flex-shrink: 0;
}

.lang-switch {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--color-hairline);
  border-radius: var(--rounded-sm);
  overflow: hidden;
}

.lang-btn {
  appearance: none;
  border: none;
  background: transparent;
  font-family: inherit;
  font-size: 13px;
  font-weight: 500;
  line-height: 1;
  padding: 8px 10px;
  color: var(--color-muted);
  cursor: pointer;
}

.lang-btn.active {
  background: var(--color-primary);
  color: var(--color-on-primary);
}

.mobile-lang {
  margin: var(--spacing-sm) 0;
  width: fit-content;
}

.nav-link {
  font-size: 14px;
  color: var(--color-body);
  white-space: nowrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  font-weight: 500;
  line-height: 1.4;
  border: none;
  cursor: pointer;
  font-family: inherit;
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-on-primary);
  padding: 16px 24px;
  border-radius: var(--rounded-lg);
  box-shadow: 0 1px 3px rgba(27, 97, 201, 0.12);
}

.btn-primary:active { background: var(--color-primary-active); }

.btn-secondary {
  background: var(--color-canvas);
  color: var(--color-ink);
  padding: 16px 24px;
  border-radius: var(--rounded-lg);
  border: 1px solid var(--color-hairline);
}

.btn-secondary-on-dark {
  background: var(--color-canvas);
  color: var(--color-ink);
  padding: 16px 24px;
  border-radius: var(--rounded-lg);
  border: 1px solid var(--color-hairline);
}

.btn-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  margin-top: var(--spacing-xl);
}

/* Hero */
.hero-band {
  padding: var(--spacing-section) 0;
  text-align: center;
}

.hero-band .subtitle {
  font-size: 18px;
  font-weight: 400;
  line-height: 1.5;
  color: var(--color-body);
  max-width: 560px;
  margin: var(--spacing-lg) auto 0;
}

.hero-illustration {
  margin-top: var(--spacing-xxl);
  border-radius: 0;
  width: 100%;
  max-height: 480px;
  object-fit: cover;
}

/* Logo strip */
.logo-strip {
  padding: var(--spacing-xl) 0;
  border-top: 1px solid var(--color-hairline);
  border-bottom: 1px solid var(--color-hairline);
}

.logo-strip .container {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--spacing-xl);
}

.logo-item {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-muted);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

/* Signature cards */
.signature-card {
  border-radius: var(--rounded-lg);
  padding: var(--spacing-xxl);
  margin: var(--spacing-section) 0;
}

.signature-coral {
  background: var(--color-signature-coral);
  color: var(--color-on-primary);
}

.signature-coral .display-md,
.signature-coral .body-md { color: var(--color-on-primary); }

.signature-coral .body-md { opacity: 0.9; max-width: 560px; margin-top: var(--spacing-md); }

.signature-forest {
  background: var(--color-signature-forest);
  color: var(--color-on-primary);
}

.signature-forest .display-md,
.signature-forest .body-md { color: var(--color-on-primary); }

.signature-forest .body-md { opacity: 0.9; max-width: 560px; margin-top: var(--spacing-md); }

.signature-dark {
  background: var(--color-surface-dark);
  color: var(--color-on-primary);
}

.signature-dark .display-md,
.signature-dark .body-md { color: var(--color-on-primary); }

.signature-dark .body-md { opacity: 0.85; max-width: 560px; margin-top: var(--spacing-md); }

.signature-card .card-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xxl);
  align-items: center;
}

.signature-card .card-content { }

.signature-card img {
  border-radius: var(--rounded-md);
  width: 100%;
  aspect-ratio: 4/3;
  object-fit: cover;
}

/* Editorial sections */
.editorial-section {
  padding: var(--spacing-section) 0;
}

.editorial-section .section-header {
  max-width: 640px;
  margin-bottom: var(--spacing-xxl);
}

.editorial-section .section-header p {
  margin-top: var(--spacing-md);
  color: var(--color-body);
  line-height: 1.5;
}

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xxl);
  align-items: start;
}

.feature-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.feature-list li {
  padding-left: var(--spacing-lg);
  border-left: 2px solid var(--color-hairline);
}

.feature-list .label-md { margin-bottom: var(--spacing-xs); }

.feature-list p { color: var(--color-body); line-height: 1.5; }

/* Demo grid */
.demo-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
  margin-top: var(--spacing-xxl);
}

.demo-card {
  border-radius: var(--rounded-md);
  padding: var(--spacing-md);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.demo-card:nth-child(1) { background: var(--color-signature-peach); margin-top: 0; }
.demo-card:nth-child(2) { background: var(--color-signature-mint); margin-top: var(--spacing-xl); }
.demo-card:nth-child(3) { background: var(--color-signature-yellow); margin-top: var(--spacing-sm); }
.demo-card:nth-child(4) { background: var(--color-signature-mustard); margin-top: var(--spacing-lg); }
.demo-card:nth-child(5) { background: var(--color-surface-soft); margin-top: 0; }
.demo-card:nth-child(6) { background: var(--color-signature-cream); margin-top: var(--spacing-xxl); }

.demo-card img {
  border-radius: var(--rounded-md);
  width: 100%;
  aspect-ratio: 16/10;
  object-fit: cover;
}

.demo-card p {
  font-size: 14px;
  line-height: 1.4;
  color: var(--color-body);
}

/* Stats row */
.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-lg);
  margin-top: var(--spacing-xxl);
  padding-top: var(--spacing-xxl);
  border-top: 1px solid var(--color-hairline);
}

.stat-item .stat-value {
  font-size: 32px;
  font-weight: 400;
  line-height: 1.2;
  color: var(--color-ink);
}

.stat-item .stat-label {
  font-size: 14px;
  color: var(--color-muted);
  margin-top: var(--spacing-xs);
  line-height: 1.4;
}

/* Cream callout */
.cream-callout {
  background: var(--color-signature-cream);
  border-radius: var(--rounded-md);
  padding: var(--spacing-lg);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xxl);
  align-items: center;
}

.cream-callout img {
  border-radius: var(--rounded-md);
  width: 100%;
  aspect-ratio: 4/3;
  object-fit: cover;
}

.cream-callout p { line-height: 1.5; margin-top: var(--spacing-md); }

/* Tabbed feature */
.feature-card-tabbed {
  background: var(--color-surface-soft);
  border-radius: var(--rounded-lg);
  padding: var(--spacing-xl);
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: var(--spacing-xl);
  margin-top: var(--spacing-xxl);
}

.tab-rail {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.tab-btn {
  background: none;
  border: none;
  text-align: left;
  padding: var(--spacing-sm) var(--spacing-md);
  font-family: inherit;
  font-size: 20px;
  font-weight: 400;
  line-height: 1.5;
  color: var(--color-muted);
  cursor: pointer;
  border-radius: var(--rounded-sm);
}

.tab-btn.active {
  color: var(--color-ink);
  background: var(--color-canvas);
}

.tab-pane { display: none; }
.tab-pane.active { display: block; }

.tab-pane p { margin-top: var(--spacing-md); line-height: 1.5; }

.tab-pane img {
  margin-top: var(--spacing-lg);
  border-radius: var(--rounded-md);
  width: 100%;
  max-height: 280px;
  object-fit: cover;
}

/* FAQ */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-top: var(--spacing-xxl);
  border-top: 1px solid var(--color-hairline);
}

.faq-item {
  border-bottom: 1px solid var(--color-hairline);
  padding: var(--spacing-lg) 0;
}

.faq-item .title-sm { margin-bottom: var(--spacing-sm); }

.faq-item p { line-height: 1.5; color: var(--color-body); }

/* Contact */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
  margin-top: var(--spacing-xxl);
}

.contact-card {
  padding: var(--spacing-xl);
  border: 1px solid var(--color-hairline);
  border-radius: var(--rounded-md);
}

.contact-card .label-md { margin-bottom: var(--spacing-sm); }

.contact-card p,
.contact-card a { font-size: 14px; line-height: 1.5; color: var(--color-body); }

/* CTA band */
.cta-band-light {
  background: var(--color-surface-strong);
  border-radius: var(--rounded-lg);
  padding: var(--spacing-xxl);
  text-align: center;
  margin: var(--spacing-section) 0;
}

.cta-band-light p {
  margin-top: var(--spacing-md);
  max-width: 480px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.5;
}

.cta-band-light .btn-group { justify-content: center; }

/* Footer */
.footer {
  padding: var(--spacing-section) 0 var(--spacing-xxl);
  border-top: 1px solid var(--color-hairline);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(4, 1fr);
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xxl);
}

.footer-brand .wordmark { margin-bottom: var(--spacing-md); }

.footer-brand p {
  font-size: 14px;
  line-height: 1.5;
  color: var(--color-muted);
  max-width: 280px;
}

.footer-col h4 {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-ink);
  margin-bottom: var(--spacing-md);
}

.footer-col ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.footer-col a {
  font-size: 14px;
  color: var(--color-muted);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--color-hairline);
  font-size: 14px;
  color: var(--color-muted);
}

/* Hamburger */
.hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-xs);
  flex-direction: column;
  gap: 5px;
}

.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-ink);
  border-radius: 1px;
}

.mobile-menu {
  display: none;
  position: fixed;
  inset: 64px 0 0 0;
  background: var(--color-canvas);
  z-index: 99;
  padding: var(--spacing-xl);
  flex-direction: column;
  gap: var(--spacing-lg);
}

.mobile-menu.open { display: flex; }

.mobile-menu a {
  font-size: 20px;
  color: var(--color-ink);
  padding: var(--spacing-sm) 0;
  border-bottom: 1px solid var(--color-hairline);
}

.mobile-menu a.active { font-weight: 500; }

/* Responsive */
@media (max-width: 1024px) {
  .demo-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-row { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(3, 1fr); }
  .contact-grid { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  .display-lg { font-size: 32px; }
  .display-md { font-size: 26px; }

  .nav-menu, .nav-actions .nav-link { display: none; }
  .nav-actions .btn-primary { display: none; }
  .hamburger { display: flex; }

  .signature-card .card-grid,
  .two-col,
  .cream-callout,
  .feature-card-tabbed { grid-template-columns: 1fr; }

  .feature-card-tabbed { padding: var(--spacing-lg); }

  .tab-rail {
    flex-direction: row;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
  }

  .tab-btn { font-size: 16px; padding: var(--spacing-xs) var(--spacing-sm); }

  .demo-grid { grid-template-columns: 1fr; }
  .demo-card { margin-top: 0 !important; }

  .stats-row { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }

  .container { padding: 0 var(--spacing-lg); }

  .editorial-section,
  .hero-band { padding: 64px 0; }

  .signature-card { margin: 64px 0; }
}