/* ---------- 语言切换：默认隐藏，按 <html lang> 显示 ---------- */
.zh,
.en {
  display: none;
}
html[lang^="zh"] .zh,
html[lang^="en"] .en {
  display: revert;
}

/* ---------- 基础 ---------- */
:root {
  --ink: #0f172a;
  --ink-soft: #475569;
  --line: #e2e8f0;
  --bg: #ffffff;
  --bg-alt: #f8fafc;
  --brand: #1d4ed8;
  --brand-dark: #1e3a8a;
  --radius: 14px;
  --wrap: 1080px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Inter", "Helvetica Neue", -apple-system, BlinkMacSystemFont,
    "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    "Noto Sans SC", sans-serif;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--brand);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

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

/* ---------- 顶栏 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 68px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
  text-decoration: none;
}

.brand:hover {
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: var(--ink);
  color: #fff;
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.04em;
  flex: 0 0 auto;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.25;
}

.brand-text strong {
  font-size: 15px;
  font-weight: 650;
  letter-spacing: -0.01em;
}

.brand-text small {
  font-size: 12px;
  color: var(--ink-soft);
}

.nav {
  display: flex;
  align-items: center;
  gap: 22px;
  font-size: 14px;
}

.nav a {
  color: var(--ink-soft);
}

.nav a:hover {
  color: var(--ink);
  text-decoration: none;
}

.lang-btn {
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  color: var(--ink-soft);
  font: inherit;
  font-size: 13px;
  cursor: pointer;
}

.lang-btn:hover {
  border-color: #cbd5e1;
  color: var(--ink);
}

/* ---------- Hero ---------- */
.hero {
  padding: 96px 0 88px;
  background:
    radial-gradient(900px 420px at 12% -10%, #e0e7ff 0%, transparent 62%),
    radial-gradient(700px 380px at 96% 8%, #e0f2fe 0%, transparent 58%),
    var(--bg);
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  margin: 0 0 20px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--brand);
}

.hero h1 {
  margin: 0 0 22px;
  max-width: 20em;
  font-size: clamp(30px, 4.6vw, 52px);
  line-height: 1.18;
  letter-spacing: -0.026em;
  font-weight: 700;
}

.hero-sub {
  margin: 0 0 34px;
  max-width: 62ch;
  font-size: 17px;
  color: var(--ink-soft);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 22px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 600;
  border: 1px solid transparent;
}

.btn:hover {
  text-decoration: none;
}

.btn-primary {
  background: var(--ink);
  color: #fff;
}

.btn-primary:hover {
  background: var(--brand-dark);
}

.btn-ghost {
  border-color: var(--line);
  color: var(--ink);
  background: #fff;
}

.btn-ghost:hover {
  border-color: #cbd5e1;
}

/* ---------- 章节 ---------- */
.section {
  padding: 78px 0;
}

.section-alt {
  background: var(--bg-alt);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.section h2 {
  margin: 0 0 32px;
  font-size: 26px;
  letter-spacing: -0.02em;
  font-weight: 680;
}

.about-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 48px;
  align-items: start;
}

.about-grid p {
  margin: 0 0 16px;
  color: var(--ink-soft);
}

.facts {
  margin: 0;
  padding: 26px 28px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.facts dt {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: #94a3b8;
}

.facts dd {
  margin: 4px 0 18px;
  font-size: 15px;
  color: var(--ink);
}

.facts dd:last-child {
  margin-bottom: 0;
}

/* ---------- 服务卡片 ---------- */
.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

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

.card h3 {
  margin: 0 0 12px;
  font-size: 17px;
  font-weight: 650;
}

.card p {
  margin: 0;
  font-size: 15px;
  color: var(--ink-soft);
}

/* ---------- 联系 ---------- */
.contact-lead {
  margin: 0 0 32px;
  max-width: 62ch;
  color: var(--ink-soft);
}

.contact-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.contact-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: 15px;
}

.contact-label {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: #94a3b8;
}

.contact-item a {
  word-break: break-all;
}

/* ---------- 页脚 ---------- */
.site-footer {
  padding: 34px 0;
  border-top: 1px solid var(--line);
  background: #fff;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px;
  font-size: 13px;
  color: #94a3b8;
}

.footer-inner p {
  margin: 0;
}

/* ---------- 响应式 ---------- */
@media (max-width: 860px) {
  .about-grid,
  .cards,
  .contact-grid {
    grid-template-columns: 1fr;
  }

  .about-grid {
    gap: 28px;
  }

  .hero {
    padding: 64px 0 60px;
  }

  .section {
    padding: 56px 0;
  }

  .nav {
    gap: 16px;
  }

  .nav a {
    display: none;
  }
}

@media (max-width: 420px) {
  .brand-text small {
    display: none;
  }
}