:root {
  --navy: #0f2942;
  --navy-dark: #0a1c2e;
  --accent: #c9932e;
  --ink: #1a1f24;
  --muted: #5b6570;
  --bg-alt: #f5f6f8;
  --border: #e4e7eb;
  --radius: 10px;
  --max-width: 1120px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  color: var(--ink);
  line-height: 1.6;
  background: #fff;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

h1, h2, h3 { margin: 0 0 16px; font-weight: 700; line-height: 1.2; }
p { margin: 0 0 16px; color: var(--muted); }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--border);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  color: var(--navy);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.logo-mark {
  height: 26px;
  width: auto;
  display: block;
}

.nav {
  display: flex;
  gap: 32px;
}

.nav a {
  color: var(--ink);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
}

.nav a:hover { color: var(--navy); }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 32px;
  height: 32px;
  background: none;
  border: none;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--navy);
  border-radius: 2px;
}

/* Hero */
.hero {
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-dark) 100%);
  color: #fff;
  padding: 120px 0 100px;
}

.hero-inner { max-width: 720px; }

.hero h1 {
  font-size: clamp(32px, 5vw, 52px);
  color: #fff;
  letter-spacing: -0.02em;
}

.hero-sub {
  font-size: 18px;
  color: rgba(255,255,255,0.8);
  max-width: 560px;
}

.hero-meta {
  font-size: 14px;
  color: rgba(255,255,255,0.55);
  margin-top: -4px;
}

.hero-cta {
  display: flex;
  gap: 16px;
  margin-top: 32px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 14px 28px;
  border-radius: 6px;
  font-weight: 600;
  font-size: 15px;
  text-decoration: none;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, opacity 0.15s ease;
}

.btn:hover { transform: translateY(-1px); }

.btn-primary {
  background: var(--accent);
  color: var(--navy-dark);
}

.btn-primary:hover { opacity: 0.92; }

.btn-secondary {
  background: transparent;
  color: #fff;
  border-color: rgba(255,255,255,0.4);
}

.btn-secondary:hover { border-color: #fff; }

/* Sections */
.section { padding: 88px 0; }
.section-alt { background: var(--bg-alt); }

.section h2 {
  font-size: clamp(26px, 3.5vw, 34px);
  letter-spacing: -0.01em;
}

.section-sub {
  max-width: 560px;
  font-size: 16px;
  margin-bottom: 40px;
}

.grid { display: grid; gap: 28px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 28px;
}

.card-icon {
  font-size: 13px;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.08em;
  margin-bottom: 12px;
}

.card h3 { font-size: 19px; }
.card p { margin: 0; font-size: 15px; }

/* Engagement model flow */
.flow {
  display: flex;
  align-items: flex-start;
  flex-wrap: nowrap;
  overflow-x: auto;
  padding-bottom: 8px;
}

.flow-step {
  flex: 1 0 200px;
  min-width: 200px;
}

.flow-step h3 {
  font-size: 20px;
  margin-bottom: 16px;
}

.flow-step ul {
  margin: 0;
  padding-left: 20px;
}

.flow-step li {
  font-size: 15px;
  color: var(--muted);
  margin-bottom: 8px;
}

.flow-arrow {
  flex: 0 0 100px;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 44px;
  margin-top: 34px;
  color: var(--accent);
}

.flow-arrow svg {
  width: 100%;
  height: 32px;
  display: block;
}

.track-header { margin-bottom: 12px; }
.track-header h3 { margin-bottom: 4px; }

.track-role {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
}

.patents-note {
  font-size: 14px;
  color: var(--muted);
  margin-top: 8px;
}

.about-inner { max-width: 720px; }

/* Contact */
.contact-inner { max-width: 560px; }

.contact-info {
  list-style: none;
  margin: 0 0 40px;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.contact-info li {
  display: flex;
  gap: 8px;
  font-size: 15px;
}

.contact-info strong {
  min-width: 80px;
  color: var(--ink);
}

.contact-info a {
  color: var(--navy);
  text-decoration: none;
}

.contact-info a:hover { text-decoration: underline; }

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-row {
  display: flex;
  gap: 16px;
}

.contact-form input,
.contact-form textarea {
  width: 100%;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-family: inherit;
  font-size: 15px;
  background: #fff;
}

.contact-form input:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: var(--navy);
}

.contact-form button { align-self: flex-start; }

.form-note {
  font-size: 14px;
  color: var(--navy);
  margin: 0;
}

/* Footer */
.site-footer {
  background: var(--navy-dark);
  color: rgba(255,255,255,0.6);
  padding: 28px 0;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.footer-mark { height: 18px; width: auto; opacity: 0.8; }

.footer-inner p { margin: 0; font-size: 14px; color: rgba(255,255,255,0.6); }

/* Responsive */
@media (max-width: 960px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 860px) {
  .grid-3 { grid-template-columns: 1fr; }
  .grid-4 { grid-template-columns: 1fr; }
  .form-row { flex-direction: column; }
}

@media (max-width: 720px) {
  .nav {
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: #fff;
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 16px 24px;
    display: none;
    gap: 16px;
  }
  .nav.open { display: flex; }
  .nav-toggle { display: flex; }
}