:root {
  --ink: #192029;
  --muted: #65717f;
  --line: #dfe5ea;
  --panel: #ffffff;
  --soft: #f5f7f8;
  --teal: #047c7a;
  --coral: #d95f43;
  --amber: #b7791f;
  --green: #337a42;
  --shadow: 0 18px 44px rgba(25, 32, 41, 0.1);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: Inter, "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  background: var(--soft);
}

a {
  color: inherit;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 72px;
  padding: 0 clamp(20px, 5vw, 72px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  background: rgba(17, 24, 32, 0.86);
  backdrop-filter: blur(18px) saturate(130%);
  box-shadow: 0 12px 28px rgba(8, 15, 25, 0.14);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: #fff;
  font-weight: 800;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 8px;
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.28);
  background: linear-gradient(135deg, rgba(4, 124, 122, 0.96), rgba(51, 122, 66, 0.9));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.18), 0 10px 22px rgba(4, 124, 122, 0.22);
  font-size: 13px;
  font-weight: 900;
  letter-spacing: 0;
}

.brand-name {
  font-size: 17px;
  letter-spacing: 0;
  white-space: nowrap;
}

.top-nav {
  display: flex;
  gap: clamp(16px, 3vw, 28px);
  align-items: center;
  color: rgba(255, 255, 255, 0.72);
  font-size: 14px;
  font-weight: 700;
}

.top-nav a {
  position: relative;
  display: inline-flex;
  align-items: center;
  min-height: 72px;
  text-decoration: none;
  transition: color 160ms ease;
}

.top-nav a:hover {
  color: #fff;
}

.top-nav a::after {
  position: absolute;
  right: 0;
  bottom: 17px;
  left: 0;
  height: 2px;
  border-radius: 999px;
  content: "";
  background: #70d8cf;
  opacity: 0;
  transform: scaleX(0.42);
  transition: opacity 160ms ease, transform 160ms ease;
}

.top-nav a:hover::after {
  opacity: 1;
  transform: scaleX(1);
}

.hero {
  position: relative;
  overflow: hidden;
  display: grid;
  min-height: clamp(520px, 72vh, 760px);
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 5vw, 72px);
  align-items: center;
  padding: clamp(72px, 10vw, 128px) clamp(20px, 5vw, 72px);
  background:
    linear-gradient(90deg, rgba(8, 15, 25, 0.76) 0%, rgba(8, 15, 25, 0.54) 36%, rgba(8, 15, 25, 0.12) 72%, rgba(8, 15, 25, 0.04) 100%),
    linear-gradient(180deg, rgba(8, 15, 25, 0.03), rgba(8, 15, 25, 0.18)),
    url("./assets/hero-beijing-tech.png") center / cover no-repeat;
  isolation: isolate;
}

.hero::after {
  position: absolute;
  inset: auto 0 0;
  height: 42%;
  content: "";
  background: linear-gradient(180deg, transparent, rgba(8, 15, 25, 0.24));
  pointer-events: none;
  z-index: -1;
}

.hero-copy {
  max-width: 880px;
}

.hero .eyebrow {
  color: #70d8cf;
}

.hero h1 {
  color: #fff;
  text-shadow: 0 14px 34px rgba(0, 0, 0, 0.28);
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--teal);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  max-width: 820px;
  margin-bottom: 22px;
  font-size: clamp(40px, 6vw, 76px);
  line-height: 1.04;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 0;
  font-size: clamp(28px, 4vw, 46px);
  line-height: 1.12;
  letter-spacing: 0;
}

.hero-text {
  max-width: 720px;
  margin-bottom: 0;
  color: rgba(255, 255, 255, 0.84);
  font-size: clamp(16px, 2vw, 20px);
  line-height: 1.8;
}

.hero-panel {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--line);
  box-shadow: var(--shadow);
}

.hero-panel > div {
  min-height: 150px;
  padding: 24px;
  background: #fff;
}

.metric {
  display: block;
  color: var(--coral);
  font-size: clamp(36px, 5vw, 54px);
  font-weight: 850;
  line-height: 1;
}

.metric-label {
  display: block;
  margin-top: 10px;
  color: var(--muted);
  font-size: 13px;
}

.section {
  padding: clamp(52px, 7vw, 96px) clamp(20px, 5vw, 72px);
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 28px;
}

.section-lead {
  max-width: 820px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.9;
}

.business-section {
  background: #fff;
}

.business-layout {
  width: 100%;
}

.business-core {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 430px;
  padding: clamp(28px, 4vw, 42px);
  border: 1px solid rgba(4, 124, 122, 0.24);
  border-radius: 8px;
  background:
    linear-gradient(150deg, rgba(4, 124, 122, 0.11), transparent 46%),
    linear-gradient(330deg, rgba(51, 122, 66, 0.13), transparent 38%),
    #f8fcfb;
}

.core-icon {
  display: grid;
  width: 58px;
  height: 58px;
  place-items: center;
  margin-bottom: 28px;
  border-radius: 8px;
  color: #fff;
  background: linear-gradient(135deg, var(--teal), var(--green));
  font-weight: 900;
  letter-spacing: 0;
}

.business-core h3,
.business-card h3 {
  margin: 0;
  letter-spacing: 0;
}

.business-core h3 {
  max-width: 420px;
  font-size: clamp(28px, 4vw, 44px);
  line-height: 1.14;
}

.business-core p {
  max-width: 500px;
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.85;
}

.business-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 18px;
}

.business-card {
  min-height: 100%;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 1px 0 rgba(25, 32, 41, 0.03);
}

.business-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 32px;
  margin-bottom: 18px;
  border-radius: 8px;
  color: var(--teal);
  background: rgba(4, 124, 122, 0.1);
  font-size: 13px;
  font-weight: 850;
}

.business-card h3 {
  font-size: 18px;
  line-height: 1.34;
}

.business-card p {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.75;
}

.project-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.project-card {
  display: grid;
  overflow: hidden;
  min-height: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  text-decoration: none;
  box-shadow: 0 1px 0 rgba(25, 32, 41, 0.03);
  transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.project-card:hover {
  transform: translateY(-4px);
  border-color: rgba(4, 124, 122, 0.34);
  box-shadow: var(--shadow);
}

.project-card:focus-visible {
  outline: 3px solid rgba(4, 124, 122, 0.32);
  outline-offset: 4px;
}

.project-card img {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  background: #dfe5ea;
}

.project-body {
  display: grid;
  gap: 10px;
  padding: 22px;
}

.project-kicker {
  color: var(--amber);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

.project-title {
  font-size: 22px;
  font-weight: 850;
  line-height: 1.2;
}

.project-desc {
  color: var(--muted);
  font-size: 15px;
  line-height: 1.7;
}

.contact-band {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  margin: 0 clamp(20px, 5vw, 72px) clamp(28px, 4vw, 52px);
  padding: clamp(28px, 5vw, 48px);
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.contact-link {
  display: inline-flex;
  align-items: center;
  min-height: 46px;
  padding: 0 18px;
  border-radius: 8px;
  color: #fff;
  background: var(--ink);
  font-weight: 750;
  text-decoration: none;
  white-space: nowrap;
}

.site-footer {
  padding: 26px clamp(20px, 5vw, 72px);
  border-top: 1px solid rgba(223, 229, 234, 0.92);
  background: #111820;
  color: rgba(255, 255, 255, 0.72);
  text-align: center;
}

.site-footer p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
}

.demo-main {
  min-height: calc(100vh - 72px);
  padding: clamp(36px, 7vw, 90px) clamp(20px, 5vw, 72px);
  background: #fbfcfc;
}

.demo-layout {
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(300px, 1.08fr);
  gap: clamp(28px, 5vw, 64px);
  align-items: center;
}

.demo-cover {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.demo-copy p {
  color: var(--muted);
  font-size: 18px;
  line-height: 1.8;
}

.feature-list {
  display: grid;
  gap: 12px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.feature-list li {
  padding: 14px 16px;
  border-left: 4px solid var(--green);
  background: #eef6f1;
  color: #26342a;
}

.back-link {
  display: inline-flex;
  margin-top: 30px;
  color: var(--teal);
  font-weight: 800;
  text-decoration: none;
}

@media (max-width: 1180px) {
  .business-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 980px) {
  .hero,
  .business-layout,
  .demo-layout {
    grid-template-columns: 1fr;
  }

  .business-core {
    min-height: 0;
  }

  .project-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 760px) {
  .business-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 640px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    justify-content: center;
    gap: 12px;
    min-height: 108px;
    padding-top: 14px;
    padding-bottom: 14px;
  }

  .top-nav {
    width: 100%;
    justify-content: space-between;
    gap: 12px;
    font-size: 13px;
  }

  .top-nav a {
    min-height: 28px;
  }

  .top-nav a::after {
    bottom: -5px;
  }

  .hero-panel,
  .business-grid,
  .project-grid {
    grid-template-columns: 1fr;
  }

  .section-heading,
  .contact-band {
    align-items: flex-start;
    flex-direction: column;
  }

  .contact-link {
    width: 100%;
    justify-content: center;
    white-space: normal;
  }

  .hero {
    min-height: 560px;
    background:
      linear-gradient(90deg, rgba(8, 15, 25, 0.82) 0%, rgba(8, 15, 25, 0.58) 64%, rgba(8, 15, 25, 0.22) 100%),
      linear-gradient(180deg, rgba(8, 15, 25, 0.04), rgba(8, 15, 25, 0.2)),
      url("./assets/hero-beijing-tech.png") 58% center / cover no-repeat;
  }
}