:root {
  --navy-950: #001b3d;
  --navy-900: #002c64;
  --navy-800: #0a3a80;
  --navy-700: #003e8f;
  --accent-700: #184189;
  --sky-400: #4a93dd;
  --us-red: #e2001a;
  --cn-teal: #1b6b6b;
  --off-white: #f7f6f3;
  --gray-100: #eceae5;
  --gray-400: #8b8f98;
  --gray-600: #565b66;
  --text-body: #363a44;
  --radius: 10px;
  --max-width: 1160px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 41, 0.06), 0 1px 3px rgba(15, 23, 41, 0.08);
  --shadow-md: 0 8px 24px rgba(15, 23, 41, 0.10);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
  color: var(--text-body);
  background: var(--off-white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: "Georgia", "Times New Roman", serif;
  color: var(--navy-900);
  line-height: 1.2;
  margin: 0 0 0.5em;
  font-weight: 600;
}

h1 { font-size: clamp(2rem, 4vw, 3rem); }
h2 { font-size: clamp(1.6rem, 3vw, 2.2rem); }
h3 { font-size: 1.25rem; }
p { margin: 0 0 1em; }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

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

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 26px;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  border: 1px solid transparent;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease, color 0.15s ease;
}

.btn-primary { background: var(--navy-700); color: #fff; }
.btn-primary:hover { background: var(--accent-700); box-shadow: var(--shadow-md); }

.btn-outline {
  background: transparent;
  color: var(--off-white);
  border-color: rgba(247, 246, 243, 0.4);
}
.btn-outline:hover { border-color: var(--off-white); background: rgba(247, 246, 243, 0.08); }

.btn-dark { background: var(--navy-900); color: var(--off-white); }
.btn-dark:hover { background: var(--navy-800); }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--navy-950);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
}

.logo {
  display: flex;
  align-items: center;
  color: var(--off-white);
  background: var(--off-white);
  padding: 8px 16px;
  border-radius: 8px;
}
.logo-img { height: 34px; width: auto; }

.nav-menu {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-menu a {
  color: rgba(247, 246, 243, 0.85);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 6px 2px;
  border-bottom: 2px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.nav-menu a:hover, .nav-menu a.active {
  color: var(--off-white);
  border-bottom-color: var(--sky-400);
}

.header-right { display: flex; align-items: center; gap: 20px; }

.lang-switch { display: flex; align-items: center; }

.lang-switch select {
  appearance: none;
  -webkit-appearance: none;
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: rgba(255, 255, 255, 0.06) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M1 1l4 4 4-4' stroke='%23f7f6f3' stroke-width='1.5' fill='none' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") no-repeat right 12px center;
  color: var(--off-white);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  padding: 8px 30px 8px 14px;
  border-radius: 999px;
  cursor: pointer;
}
.lang-switch select:hover { border-color: rgba(255, 255, 255, 0.35); }
.lang-switch select option { color: var(--text-body); background: #fff; }

.nav-cta {
  background: var(--navy-700);
  color: #fff;
  padding: 10px 20px;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 700;
  white-space: nowrap;
}
.nav-cta:hover { background: var(--accent-700); }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 8px;
}
.nav-toggle span { width: 24px; height: 2px; background: var(--off-white); display: block; }

/* Hero */
.hero {
  background:
    linear-gradient(160deg, rgba(0, 27, 61, 0.94), rgba(0, 44, 100, 0.90)),
    repeating-linear-gradient(135deg, rgba(74, 147, 221, 0.08) 0px, rgba(74, 147, 221, 0.08) 2px, transparent 2px, transparent 40px);
  color: var(--off-white);
  padding: 100px 0 80px;
}

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

.eyebrow {
  display: inline-block;
  color: var(--sky-400);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  margin-bottom: 18px;
}

.hero h1 { color: var(--off-white); margin-bottom: 20px; }
.hero p.lead { font-size: 1.15rem; color: rgba(247, 246, 243, 0.82); max-width: 580px; margin-bottom: 34px; }
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; }

.page-hero {
  background: var(--navy-950);
  color: var(--off-white);
  padding: 72px 0 56px;
}
.page-hero h1 { color: var(--off-white); }
.page-hero p { color: rgba(247, 246, 243, 0.78); font-size: 1.05rem; max-width: 640px; }

/* Sections */
.section { padding: 80px 0; }
.section-alt { background: var(--gray-100); }

.section-head { max-width: 640px; margin: 0 auto 48px; text-align: center; }
.section-head p { color: var(--gray-600); font-size: 1.05rem; }

.explain-box {
  max-width: 820px;
  margin: 0 auto;
  background: #fff;
  border-radius: var(--radius);
  padding: 40px;
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(15, 23, 41, 0.06);
  text-align: center;
}
.explain-box h2 { margin-bottom: 16px; }
.explain-box p { color: var(--gray-600); font-size: 1.05rem; margin-bottom: 0; }

/* Brand cards */
.grid { display: grid; gap: 28px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }

.brand-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 40px 36px;
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(15, 23, 41, 0.06);
  border-top: 4px solid var(--brand-color, var(--navy-700));
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  display: flex;
  flex-direction: column;
}
.brand-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.brand-card.us { --brand-color: var(--us-red); }
.brand-card.cn { --brand-color: var(--cn-teal); }

.brand-card-logo { height: 46px; width: auto; margin-bottom: 24px; }
.brand-card-logo.logo-us { height: 64px; }
.brand-card h3 { margin-bottom: 10px; }
.brand-card p { color: var(--gray-600); flex-grow: 1; }
.brand-card a.btn { align-self: flex-start; margin-top: 12px; }

/* Feature cards */
.card {
  background: #fff;
  border-radius: var(--radius);
  padding: 32px 28px;
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(15, 23, 41, 0.06);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }

.card-icon {
  width: 46px;
  height: 46px;
  border-radius: 10px;
  background: var(--navy-950);
  color: var(--sky-400);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 18px;
  font-size: 1.3rem;
}
.card h3 { margin-bottom: 8px; }
.card p { color: var(--gray-600); margin-bottom: 0; font-size: 0.95rem; }

/* Brand page intro */
.two-col { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 56px; align-items: start; }

.brand-panel {
  border-radius: var(--radius);
  padding: 36px 32px;
  color: var(--off-white);
  background: linear-gradient(150deg, var(--navy-950), var(--navy-800));
}
.brand-panel.us { background: linear-gradient(150deg, var(--navy-950), #7a0010); }
.brand-panel.cn { background: linear-gradient(150deg, var(--navy-950), #0e3d3d); }
.brand-panel img {
  height: 56px;
  width: auto;
  margin-bottom: 20px;
  background: #fff;
  padding: 10px 16px;
  border-radius: 10px;
}
.brand-panel img.logo-us { height: 110px; padding: 14px 20px; }
.brand-panel img.logo-cn { height: 64px; }
.brand-panel h3 { color: var(--off-white); font-size: 0.85rem; letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 14px; }
.brand-panel p { font-size: 1.05rem; color: rgba(247, 246, 243, 0.85); margin-bottom: 0; }
.brand-panel-link {
  display: inline-block;
  margin-top: 18px;
  color: #fff;
  font-weight: 700;
  text-decoration: underline;
  text-underline-offset: 3px;
}
.brand-panel-link:hover { color: var(--sky-400); }

/* CTA band */
.cta-band {
  background: linear-gradient(120deg, var(--navy-950), var(--navy-700));
  color: var(--off-white);
  padding: 64px 0;
  text-align: center;
}
.cta-band h2 { color: var(--off-white); }
.cta-band p { color: rgba(247, 246, 243, 0.78); margin-bottom: 28px; }

/* Contact */
.contact-grid { display: grid; grid-template-columns: 0.85fr 1.15fr; gap: 48px; }

.contact-info-item { display: flex; gap: 16px; margin-bottom: 26px; }
.contact-info-icon {
  width: 42px;
  height: 42px;
  flex-shrink: 0;
  border-radius: 8px;
  background: var(--navy-950);
  color: var(--sky-400);
  display: flex;
  align-items: center;
  justify-content: center;
}
.contact-info-item h4 { margin: 0 0 4px; font-family: inherit; color: var(--navy-900); font-size: 0.95rem; }
.contact-info-item p { margin: 0; color: var(--gray-600); font-size: 0.95rem; }

.form-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 36px;
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(15, 23, 41, 0.06);
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.field { margin-bottom: 18px; }
.field label { display: block; font-size: 0.85rem; font-weight: 600; color: var(--navy-800); margin-bottom: 6px; }
.field input, .field textarea {
  width: 100%;
  padding: 12px 14px;
  border-radius: 8px;
  border: 1px solid #d8d6cf;
  background: var(--off-white);
  font-family: inherit;
  font-size: 0.95rem;
  color: var(--text-body);
}
.field input:focus, .field textarea:focus { outline: none; border-color: var(--navy-700); background: #fff; }
.field textarea { resize: vertical; min-height: 130px; }
.form-note { font-size: 0.85rem; color: var(--gray-400); margin-top: 14px; margin-bottom: 0; }

/* Footer */
.site-footer { background: var(--navy-950); color: rgba(247, 246, 243, 0.75); padding: 56px 0 28px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 40px; margin-bottom: 40px; }
.footer-logo-img {
  height: 28px;
  background: var(--off-white);
  padding: 8px 14px;
  border-radius: 8px;
}
.footer-grid p { font-size: 0.9rem; margin-top: 12px; }
.footer-heading {
  color: var(--off-white);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 16px;
}
.footer-links { list-style: none; padding: 0; margin: 0; }
.footer-links li { margin-bottom: 10px; }
.footer-links a { font-size: 0.92rem; color: rgba(247, 246, 243, 0.75); }
.footer-links a:hover { color: var(--sky-400); }
.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding-top: 22px;
  font-size: 0.82rem;
  color: rgba(247, 246, 243, 0.5);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}

/* Responsive */
@media (max-width: 960px) {
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .two-col { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 720px) {
  .nav-toggle { display: flex; }
  .header-right .nav-cta { display: none; }
  .nav-menu {
    position: absolute;
    top: 76px;
    left: 0;
    right: 0;
    background: var(--navy-950);
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.25s ease;
    border-bottom: 1px solid rgba(255,255,255,0.08);
  }
  .nav-menu.open { max-height: 400px; padding: 12px 0; }
  .nav-menu li { width: 100%; }
  .nav-menu a { display: block; padding: 14px 24px; border-bottom: none; }
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; }
}