:root {
  --bg: #F7FAFC;
  --bg-alt: #EEF4F8;
  --card: #FFFFFF;
  --ink: #0F172A;
  --ink-soft: #475569;
  --ink-mute: #94A3B8;
  --line: #E2E8F0;
  --teal: #14B8A6;
  --indigo: #6366F1;
  --brand: linear-gradient(120deg, #14B8A6 0%, #4F7DF9 55%, #6366F1 100%);
  --shadow: 0 10px 30px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 20px 50px rgba(15, 23, 42, 0.10);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

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

.container {
  width: min(1120px, 92vw);
  margin: 0 auto;
}

/* 导航（logo 放大 + 下方公司名） */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(247, 250, 252, 0.82);
  backdrop-filter: saturate(180%) blur(12px);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 4px 0;
}
.brand {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  text-align: left;
  gap: 4px;
  text-decoration: none;
}
.brand-logo {
  height: 152px;
  width: auto;
  max-width: 680px;
  display: block;
}
.brand-name {
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.5px;
  color: var(--ink-soft);
}
.nav-right { display: flex; align-items: center; gap: 22px; }
.nav-links { display: flex; gap: 28px; }
.nav-links a {
  color: var(--ink-soft);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  transition: color .2s ease;
}
.nav-links a:hover { color: var(--teal); }

/* 语言切换器 */
.lang-switch { display: flex; gap: 6px; }
.lang-btn {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink-soft);
  font-size: 13px;
  font-weight: 600;
  padding: 6px 13px;
  border-radius: 999px;
  cursor: pointer;
  transition: color .2s ease, background .2s ease, border-color .2s ease;
}
.lang-btn:hover { color: var(--teal); border-color: var(--teal); }
.lang-btn.active { background: var(--brand); color: #fff; border-color: transparent; }

/* Hero */
.hero {
  position: relative;
  padding: 92px 0 108px;
  background:
    radial-gradient(900px 420px at 50% -8%, rgba(20, 184, 166, 0.16), transparent 60%),
    radial-gradient(760px 380px at 85% 8%, rgba(99, 102, 241, 0.14), transparent 60%),
    var(--bg);
  overflow: hidden;
}
.hero-inner { text-align: center; }
.hero-badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 999px;
  background: rgba(79, 125, 249, 0.10);
  color: var(--indigo);
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 22px;
}
.hero-title {
  font-size: clamp(30px, 5vw, 50px);
  font-weight: 800;
  letter-spacing: -0.5px;
  margin: 0 0 18px;
  background: var(--brand);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-sub {
  font-size: clamp(15px, 2vw, 19px);
  color: var(--ink-soft);
  margin: 0 auto 34px;
  max-width: 760px;
}
.hero-cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

.btn {
  display: inline-block;
  padding: 12px 26px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  transition: transform .15s ease, box-shadow .2s ease, background .2s ease;
}
.btn-primary {
  color: #fff;
  background: var(--brand);
  box-shadow: 0 8px 22px rgba(79, 125, 249, 0.32);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 12px 28px rgba(79, 125, 249, 0.42); }
.btn-ghost {
  color: var(--ink);
  background: #fff;
  border-color: var(--line);
}
.btn-ghost:hover { transform: translateY(-2px); box-shadow: var(--shadow); }

/* 区块 */
.section { padding: 84px 0; }
.section-alt { background: var(--bg-alt); }
.section-title {
  font-size: clamp(24px, 3.4vw, 34px);
  font-weight: 800;
  margin: 0 0 12px;
  color: var(--ink);
}
.section-desc {
  color: var(--ink-soft);
  max-width: 680px;
  margin: 0 0 40px;
  font-size: 16px;
}

/* 卡片（可点击展开） */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 22px;
}
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 30px 26px;
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: transform .18s ease, box-shadow .25s ease, border-color .2s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.card:focus-visible { outline: none; border-color: var(--teal); }
.card.open { border-color: var(--teal); }
.card-icon {
  width: 52px; height: 52px;
  border-radius: 14px;
  display: flex; align-items: center; justify-content: center;
  font-size: 24px; color: #fff;
  background: var(--brand);
  margin-bottom: 18px;
}
.card h3 { font-size: 19px; margin: 0 0 10px; color: var(--ink); }
.card > p { font-size: 14.5px; color: var(--ink-soft); margin: 0; }
.card-detail {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transition: max-height .3s ease, opacity .25s ease, margin-top .3s ease;
}
.card.open .card-detail { max-height: 520px; opacity: 1; margin-top: 14px; }
.card-detail p { font-size: 14px; color: var(--ink-soft); margin: 0 0 10px; }
.card-detail ul { margin: 0; padding-left: 18px; color: var(--ink-soft); font-size: 13.5px; }
.card-detail li { margin: 5px 0; }
.card-toggle {
  display: inline-block;
  margin-top: 16px;
  font-size: 13px;
  font-weight: 600;
  color: var(--teal);
  user-select: none;
}

/* 技术能力 */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 22px;
}
.feat {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 28px 24px;
  box-shadow: var(--shadow);
  transition: transform .18s ease, box-shadow .25s ease;
}
.feat:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.feat-ico { font-size: 30px; margin-bottom: 12px; }
.feat h4 { font-size: 18px; margin: 0 0 8px; color: var(--ink); }
.feat p { font-size: 14.5px; color: var(--ink-soft); margin: 0; }

/* 服务流程 */
.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 22px;
}
.step {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 28px 24px;
  box-shadow: var(--shadow);
  position: relative;
}
.step-no {
  font-size: 30px;
  font-weight: 800;
  background: var(--brand);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 10px;
}
.step h4 { font-size: 17px; margin: 0 0 8px; color: var(--ink); }
.step p { font-size: 14px; color: var(--ink-soft); margin: 0; }

/* 关于（左对齐，与其他区块一致） */
.about-text { max-width: 820px; }
.about-text p { color: var(--ink-soft); font-size: 16px; margin: 0 0 16px; }
.about-text p:last-child { margin-bottom: 0; }

/* 联系（仅展示，无表单） */
.contact-info { display: flex; flex-direction: column; gap: 20px; max-width: 720px; }
.info-item { display: flex; flex-direction: column; }
.info-k { font-size: 13px; color: var(--ink-mute); margin-bottom: 4px; }
.info-item a, .info-item span { font-size: 16px; color: var(--ink); font-weight: 600; text-decoration: none; }
.info-item a:hover { color: var(--teal); }

/* 页脚（版权 + 备案号同一行展示） */
.footer { background: #0F172A; color: #CBD5E1; padding: 26px 0; }
.footer-inner { text-align: center; }
.footer-bottom { font-size: 13px; color: #94A3B8; }
.footer-bottom .footer-sep { margin: 0 10px; color: #64748B; }
.footer-bottom a { color: #CBD5E1; text-decoration: none; border-bottom: 1px solid rgba(203, 213, 225, 0.5); transition: color .2s ease, border-color .2s ease; }
.footer-bottom a:hover { color: #FFFFFF; border-bottom-color: #FFFFFF; }

/* 响应式 */
@media (max-width: 820px) {
  .nav-links { gap: 18px; }
  .brand-logo { height: 120px; max-width: 540px; }
}
@media (max-width: 520px) {
  .nav-links { display: none; }
  .brand-logo { height: 104px; max-width: 460px; }
  .hero { padding: 70px 0 80px; }
}