:root {
  --bg: #ffffff;
  --surface: #ffffff;
  --surface-alt: #f5f7fb;
  --border: #e6e9f0;
  --text: #1f2430;
  --muted: #6b7280;
  --accent: #4f6bff;
  --accent-strong: #3a55e6;
  --accent-soft: rgba(79, 107, 255, 0.1);
  --shadow: 0 10px 30px rgba(31, 36, 48, 0.08);
  --radius: 14px;
  --maxw: 1080px;
  font-family: system-ui, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- nav ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 17px;
}
.brand-mark {
  width: 32px;
  height: 32px;
  border-radius: 9px;
  background: var(--accent);
  color: #fff;
  display: grid;
  place-items: center;
  font-size: 18px;
}
.brand-name {
  letter-spacing: 0.5px;
}
.nav-links {
  display: flex;
  gap: 28px;
  font-size: 15px;
  color: var(--muted);
}
.nav-links a:hover {
  color: var(--accent);
}
.nav-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 9px;
  font-size: 18px;
  padding: 6px 10px;
  cursor: pointer;
  color: var(--text);
}

/* ---------- hero ---------- */
.hero {
  padding: 96px 0 80px;
  background: radial-gradient(circle at 20% 0%, var(--accent-soft), transparent 45%),
    radial-gradient(circle at 90% 20%, rgba(124, 92, 246, 0.08), transparent 40%);
}
.eyebrow {
  color: var(--accent);
  font-weight: 600;
  letter-spacing: 1px;
  font-size: 14px;
  margin: 0 0 12px;
}
.hero h1 {
  font-size: clamp(34px, 6vw, 56px);
  line-height: 1.15;
  margin: 0 0 18px;
  letter-spacing: -0.5px;
}
.lead {
  font-size: clamp(16px, 2.4vw, 19px);
  color: var(--muted);
  max-width: 720px;
  margin: 0 0 30px;
}
.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

/* ---------- buttons ---------- */
.btn {
  display: inline-block;
  padding: 12px 22px;
  border-radius: 11px;
  font-weight: 600;
  font-size: 15px;
  transition: all 0.15s ease;
  border: 1px solid transparent;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover {
  background: var(--accent-strong);
}
.btn-ghost {
  border-color: var(--border);
  color: var(--text);
  background: #fff;
}
.btn-ghost:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ---------- sections ---------- */
.section {
  padding: 72px 0;
}
.section-alt {
  background: var(--surface-alt);
}
.section-title {
  font-size: clamp(24px, 4vw, 32px);
  margin: 0 0 22px;
  position: relative;
  padding-left: 16px;
}
.section-title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 5px;
  border-radius: 3px;
  background: var(--accent);
}
.section-body {
  font-size: 16px;
  color: #3b4252;
  max-width: 820px;
  margin: 0 0 16px;
}

/* ---------- cards ---------- */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 24px;
  box-shadow: var(--shadow);
  transition: transform 0.12s ease, border-color 0.15s ease;
}
.card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
}
.card-icon {
  font-size: 30px;
  margin-bottom: 12px;
}
.card h3 {
  margin: 0 0 14px;
  font-size: 18px;
}
.card ul {
  margin: 0;
  padding-left: 18px;
  color: var(--muted);
  font-size: 14.5px;
}
.card li {
  margin-bottom: 8px;
}

/* ---------- contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 18px;
}
.contact-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.contact-label {
  font-size: 13px;
  color: var(--muted);
}
.contact-value {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  word-break: break-word;
}

/* ---------- footer ---------- */
.site-footer {
  border-top: 1px solid var(--border);
  background: var(--surface-alt);
  padding: 26px 0;
  font-size: 13px;
  color: var(--muted);
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}
.footer-links {
  display: flex;
  gap: 14px;
}
.footer-links a:hover {
  color: var(--accent);
  text-decoration: underline;
}

/* ---------- responsive ---------- */
@media (max-width: 720px) {
  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid var(--border);
    padding: 8px 24px 16px;
    display: none;
  }
  .nav-links.open {
    display: flex;
  }
  .nav-links a {
    padding: 12px 0;
    border-bottom: 1px solid var(--border);
  }
  .nav-links a:last-child {
    border-bottom: none;
  }
  .nav-toggle {
    display: block;
  }
  .hero {
    padding: 64px 0 56px;
  }
  .section {
    padding: 52px 0;
  }
}