:root {
  --blue-50: #eff6ff;
  --blue-100: #dbeafe;
  --blue-500: #3b82f6;
  --blue-600: #2563eb;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-600: #4b5563;
  --gray-800: #1f2937;
  --white: #ffffff;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: 'Inter', system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  color: var(--gray-800);
  background: var(--white);
  line-height: 1.6;
}

.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 16px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--white);
  border-bottom: 1px solid var(--gray-200);
}
.header-inner {
  display: grid;
  grid-template-columns: auto 1fr auto auto;
  align-items: center;
  gap: 16px;
  padding: 12px 0;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  color: var(--blue-600);
  letter-spacing: 0.2px;
}
.brand-logo { width: 28px; height: 28px; display: inline-block; }
.brand.small { font-size: 14px; }
.site-nav {
  display: flex;
  gap: 16px;
}
.site-nav a {
  color: var(--gray-800);
  text-decoration: none;
  font-weight: 500;
}
.site-nav a:hover { color: var(--blue-600); }
.cta {
  background: var(--blue-600);
  color: var(--white);
  padding: 10px 14px;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 600;
}
.cta:hover { background: var(--blue-500); }
.nav-toggle {
  display: none;
  border: 1px solid var(--gray-300);
  background: var(--white);
  border-radius: 6px;
  padding: 6px 10px;
  font-size: 16px;
}

/* Sections */
.section { padding: 64px 0; }
.section h2 { margin-top: 0; font-size: 28px; }
.sub { color: var(--gray-600); }

/* Hero */
.hero {
  background: linear-gradient(180deg, var(--blue-50), var(--white));
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 24px;
  align-items: center;
}
.hero-text h1 { font-size: 34px; margin-bottom: 12px; }
.hero-actions { display: flex; gap: 12px; margin-top: 16px; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 14px;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 600;
}
.btn.primary { background: var(--blue-600); color: var(--white); }
.btn.primary:hover { background: var(--blue-500); }
.btn.secondary { background: var(--blue-100); color: var(--blue-600); }
.btn.secondary:hover { background: var(--blue-50); }
.btn.outline { border: 1px solid var(--gray-300); color: var(--gray-800); }

/* Mockup (Hero) */
.mock-window {
  display: grid;
  grid-template-columns: 180px 1fr 220px;
  border: 1px solid var(--gray-200);
  border-radius: 12px;
  background: var(--white);
  box-shadow: 0 6px 20px rgba(0,0,0,0.06);
  overflow: hidden;
}
.mock-sidebar {
  background: var(--gray-100);
  border-right: 1px solid var(--gray-200);
  padding: 12px;
}
.mock-sidebar .dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--gray-300); display: inline-block; margin-right: 6px;
}
.mock-sidebar ul { list-style: none; padding: 0; margin: 12px 0 0; }
.mock-sidebar li { padding: 8px 10px; border-radius: 6px; }
.mock-sidebar li.active { background: var(--blue-100); color: var(--blue-600); }
.mock-chat { padding: 14px; background: var(--white); }
.msg { padding: 8px 10px; border-radius: 10px; margin-bottom: 8px; width: fit-content; max-width: 90%; }
.msg.you { background: var(--blue-50); }
.msg.bot { background: var(--gray-100); }
.mock-info { background: var(--gray-50); border-left: 1px solid var(--gray-200); padding: 12px; }
.mock-info .card { border: 1px solid var(--gray-200); background: var(--white); border-radius: 8px; padding: 10px; margin-bottom: 10px; }
.label { font-size: 12px; color: var(--gray-600); }
.value { font-weight: 600; }

/* Features */
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}
.feature-card {
  border: 1px solid var(--gray-200);
  border-radius: 12px;
  padding: 18px;
  background: var(--white);
}
.feature-card .icon { font-size: 24px; }
.feature-card h3 { margin: 8px 0; font-size: 18px; }
.feature-card p { color: var(--gray-600); }

/* How */
.how .steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.step { border: 1px solid var(--gray-200); border-radius: 12px; padding: 18px; background: var(--white); display: flex; gap: 12px; align-items: flex-start; }
.step-number { width: 32px; height: 32px; border-radius: 50%; background: var(--blue-100); color: var(--blue-600); display: grid; place-items: center; font-weight: 700; }
.step-content h3 { margin: 0 0 6px 0; font-size: 18px; }
.step-content p { margin: 0; color: var(--gray-600); }

/* UI Preview */
.ui-preview .desc { color: var(--gray-600); margin-bottom: 14px; }
.ui-window { display: grid; grid-template-columns: 200px 1fr 240px; gap: 0; border: 1px solid var(--gray-200); border-radius: 12px; overflow: hidden; box-shadow: 0 6px 20px rgba(0,0,0,0.06); }
.ui-sidebar { background: var(--gray-100); border-right: 1px solid var(--gray-200); padding: 12px; }
.ui-sidebar h4 { margin: 0 0 10px; }
.ui-sidebar ul { list-style: none; padding: 0; margin: 0; }
.ui-sidebar li { padding: 8px 10px; border-radius: 6px; }
.ui-sidebar li.active { background: var(--blue-100); color: var(--blue-600); }
.ui-chat { padding: 14px; background: var(--white); }
.bubble { padding: 8px 10px; border-radius: 10px; margin-bottom: 8px; width: fit-content; max-width: 90%; }
.bubble.you { background: var(--blue-50); }
.bubble.bot { background: var(--gray-100); }
.ui-info { background: var(--gray-50); border-left: 1px solid var(--gray-200); padding: 12px; }
.info-card { border: 1px solid var(--gray-200); background: var(--white); border-radius: 8px; padding: 10px; margin-bottom: 10px; }

/* Pricing */
.pricing-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.price-card { border: 1px solid var(--gray-200); border-radius: 12px; padding: 18px; background: var(--white); }
.price-card.highlight { border-color: var(--blue-500); box-shadow: 0 6px 20px rgba(37,99,235,0.12); }
.price { font-weight: 700; margin: 8px 0; }
.subtitle { color: var(--gray-600); margin: 0; }
.features-list { list-style: none; padding: 0; margin: 12px 0; color: var(--gray-600); }
.features-list li { padding: 6px 0; }

/* Privacy */
.privacy-list { list-style: disc; padding-left: 20px; color: var(--gray-800); }
.privacy .btn.outline { margin-top: 12px; }

/* Contact */
.contact-form { border: 1px solid var(--gray-200); border-radius: 12px; padding: 18px; background: var(--white); }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.form-field { display: flex; flex-direction: column; gap: 6px; }
.form-field.full { grid-column: 1 / -1; }
label { font-size: 13px; color: var(--gray-600); }
input, textarea { border: 1px solid var(--gray-300); border-radius: 8px; padding: 10px; font-size: 14px; }
input:focus, textarea:focus { outline: none; border-color: var(--blue-500); box-shadow: 0 0 0 3px var(--blue-100); }
.form-actions { margin-top: 8px; }
.note { font-size: 12px; color: var(--gray-600); margin-top: 8px; }

/* Footer */
.site-footer { background: var(--gray-50); border-top: 1px solid var(--gray-200); }
.footer-inner { display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 12px; padding: 16px 0; }
.legal { color: var(--gray-600); font-size: 14px; }
.links { display: flex; gap: 8px; }
.links a { color: var(--gray-800); text-decoration: none; }
.links a:hover { color: var(--blue-600); }

/* Responsive */
@media (max-width: 960px) {
  .hero-grid { grid-template-columns: 1fr; }
  .mock-window { grid-template-columns: 160px 1fr; }
  .mock-info { display: none; }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .how .steps { grid-template-columns: 1fr; }
  .ui-window { grid-template-columns: 160px 1fr; }
  .ui-info { display: none; }
  .pricing-grid { grid-template-columns: 1fr; }
  .header-inner { grid-template-columns: auto auto auto; }
  .site-nav { display: none; }
  .nav-toggle { display: inline-block; }
}

@media (max-width: 560px) {
  .form-row { grid-template-columns: 1fr; }
  .hero-text h1 { font-size: 28px; }
}

/* Mobile nav open */
.site-nav.open {
  display: flex;
  flex-direction: column;
  position: absolute;
  top: 56px;
  left: 0;
  right: 0;
  background: var(--white);
  border-bottom: 1px solid var(--gray-200);
  padding: 10px 16px;
}