/* ============================================================
   ICUnit — base styles
   ============================================================ */

:root {
  --c-primary: #0b63f6;
  --c-primary-dark: #063a99;
  --c-accent: #14c8e8;
  --c-bg: #ffffff;
  --c-bg-alt: #f4f8fc;
  --c-surface: #ffffff;
  --c-border: #e4eaf2;
  --c-text: #101828;
  --c-text-muted: #51606f;
  --gradient: linear-gradient(120deg, var(--c-primary) 0%, var(--c-accent) 100%);
  --shadow-sm: 0 1px 2px rgba(16, 24, 40, 0.06);
  --shadow-md: 0 8px 24px rgba(16, 24, 40, 0.08);
  --radius: 16px;
  --font-body: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-head: "Space Grotesk", "Inter", system-ui, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --c-bg: #0a0f1a;
    --c-bg-alt: #0f1524;
    --c-surface: #131b2c;
    --c-border: #232e42;
    --c-text: #eef2f8;
    --c-text-muted: #9aa8bb;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.35);
  }
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--c-bg);
  color: var(--c-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 {
  font-family: var(--font-head);
  line-height: 1.15;
  margin: 0 0 0.5em;
  letter-spacing: -0.01em;
}

h2 { font-size: clamp(1.6rem, 3vw, 2.25rem); }
h3 { font-size: 1.15rem; }

p { margin: 0 0 1em; color: var(--c-text-muted); }

a { color: var(--c-primary); }

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

.wrap {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--c-primary);
  color: #fff;
  padding: 10px 16px;
  border-radius: 0 0 8px 0;
  z-index: 1000;
}
.skip-link:focus { left: 0; }

/* ---------- Header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in srgb, var(--c-bg) 85%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--c-border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  height: 72px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--c-text);
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.1rem;
}

.brand-logo { height: 32px; width: auto; }

.site-nav {
  display: flex;
  gap: 28px;
  flex: 1;
  justify-content: center;
}

.site-nav a {
  color: var(--c-text);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  opacity: 0.8;
  transition: opacity 0.15s ease;
}
.site-nav a:hover { opacity: 1; color: var(--c-primary); }

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.lang-toggle {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border-radius: 999px;
  border: 1px solid var(--c-border);
  background: var(--c-surface);
  color: var(--c-text);
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}
.lang-toggle:hover { border-color: var(--c-primary); }
.lang-toggle .lang-sep { opacity: 0.4; }
.lang-toggle [data-lang-label] { opacity: 0.45; }
.lang-toggle[data-active="en"] .lang-en,
.lang-toggle[data-active="zh"] .lang-zh {
  opacity: 1;
  color: var(--c-primary);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 32px;
  height: 32px;
  padding: 6px;
  border: none;
  background: transparent;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--c-text);
  border-radius: 2px;
}

/* ---------- Hero ---------- */

.hero {
  position: relative;
  padding: 96px 0 88px;
  overflow: hidden;
  text-align: center;
}

.hero-bg {
  position: absolute;
  inset: -20% -10%;
  background:
    radial-gradient(circle at 20% 20%, color-mix(in srgb, var(--c-primary) 22%, transparent), transparent 55%),
    radial-gradient(circle at 80% 30%, color-mix(in srgb, var(--c-accent) 22%, transparent), transparent 55%);
  filter: blur(10px);
  z-index: -1;
}

.hero-logo {
  height: 56px;
  width: auto;
  margin: 0 auto 28px;
}

.hero-title {
  font-size: clamp(2.4rem, 6vw, 4rem);
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 20px;
}

.hero-subtitle {
  max-width: 680px;
  margin: 0 auto 36px;
  font-size: 1.1rem;
  color: var(--c-text-muted);
}

.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 14px 26px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: transform 0.15s ease, box-shadow 0.15s ease, opacity 0.15s ease;
  border: 1px solid transparent;
}
.btn:hover { transform: translateY(-2px); }

.btn-primary {
  background: var(--gradient);
  color: #fff;
  box-shadow: var(--shadow-md);
}

.btn-ghost {
  background: transparent;
  color: var(--c-text);
  border-color: var(--c-border);
}
.btn-ghost:hover { border-color: var(--c-primary); color: var(--c-primary); }

/* ---------- Sections ---------- */

.section {
  padding: 88px 0;
}

.section.alt {
  background: var(--c-bg-alt);
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--c-primary);
  margin-bottom: 12px;
}

.section-lead {
  max-width: 700px;
  font-size: 1.05rem;
  margin-bottom: 44px;
}

.note {
  margin-top: 8px;
  font-size: 0.95rem;
  font-style: italic;
  max-width: 760px;
}

/* ---------- Cards ---------- */

.card-grid {
  display: grid;
  gap: 24px;
}
.card-grid.three { grid-template-columns: repeat(3, 1fr); }
.card-grid.two { grid-template-columns: repeat(2, 1fr); }

@media (max-width: 860px) {
  .card-grid.three,
  .card-grid.two { grid-template-columns: 1fr; }
}

.card {
  position: relative;
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 30px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}
.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.card-icon {
  font-size: 1.8rem;
  margin-bottom: 14px;
}

.card h3 { margin-bottom: 10px; }
.card p { margin: 0; font-size: 0.96rem; }

.featured-card {
  border-color: color-mix(in srgb, var(--c-accent) 40%, var(--c-border));
}

.feature-card {
  grid-column: 1 / -1;
  border: 1.5px solid transparent;
  background:
    linear-gradient(var(--c-surface), var(--c-surface)) padding-box,
    var(--gradient) border-box;
  padding: 36px;
}

.badge {
  display: inline-block;
  padding: 5px 12px;
  border-radius: 999px;
  background: var(--gradient);
  color: #fff;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 14px;
}

/* ---------- Story ---------- */

.story-inner {
  max-width: 760px;
  text-align: center;
}

.story-text {
  text-align: left;
  max-width: 620px;
  margin: 0 auto;
}

.pull-quote {
  margin: 40px auto 0;
  font-family: var(--font-head);
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 600;
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  border: none;
  padding: 0;
}

/* ---------- Sister company ---------- */

.sister-inner {
  text-align: center;
}
.sister-inner .section-lead { margin-left: auto; margin-right: auto; }

/* ---------- Contact ---------- */

.contact {
  text-align: center;
}
.contact .section-lead { margin-left: auto; margin-right: auto; }

/* ---------- Footer ---------- */

.site-footer {
  border-top: 1px solid var(--c-border);
  padding: 40px 0;
}

.footer-inner {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.footer-logo { height: 24px; width: auto; }

.footer-inner p {
  margin: 0;
  font-size: 0.85rem;
}

/* ---------- Responsive nav ---------- */

@media (max-width: 780px) {
  .site-nav {
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--c-bg);
    border-bottom: 1px solid var(--c-border);
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
    padding: 16px 24px 24px;
    display: none;
  }
  .site-nav.open { display: flex; }
  .site-nav a { padding: 10px 0; width: 100%; }
  .nav-toggle { display: flex; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .btn:hover { transform: none; }
}