:root {
  --ink: #111827;
  --muted: #5f6b7a;
  --line: #d9e0e8;
  --paper: #f7fafc;
  --white: #ffffff;
  --teal: #0f8f8c;
  --green: #5bbf59;
  --amber: #d99a2b;
  --charcoal: #121820;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

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

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

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 18px clamp(18px, 5vw, 64px);
  color: var(--white);
  transition: background 180ms ease, box-shadow 180ms ease, color 180ms ease;
}

.site-header.is-scrolled {
  color: var(--ink);
  background: rgba(255, 255, 255, 0.92);
  box-shadow: 0 10px 30px rgba(18, 24, 32, 0.08);
  backdrop-filter: blur(14px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  white-space: nowrap;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border: 1px solid currentColor;
  border-radius: 8px;
  font-size: 13px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 26px;
  font-size: 14px;
  font-weight: 600;
}

.header-action,
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border-radius: 8px;
  font-weight: 700;
  font-size: 14px;
}

.header-action {
  color: var(--white);
  background: var(--teal);
}

.site-header.is-scrolled .header-action {
  color: var(--white);
}

.hero {
  position: relative;
  min-height: 92vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  color: var(--white);
  background: var(--charcoal);
}

.hero-image {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, rgba(11, 17, 24, 0.9) 0%, rgba(11, 17, 24, 0.68) 42%, rgba(11, 17, 24, 0.12) 100%);
}

.hero-content {
  position: relative;
  width: min(760px, calc(100% - 36px));
  margin-left: clamp(18px, 7vw, 92px);
  padding-top: 78px;
}

.eyebrow,
.section-label {
  margin: 0 0 14px;
  color: var(--green);
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 22px;
  font-size: clamp(46px, 8vw, 96px);
  line-height: 0.95;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(30px, 4vw, 54px);
  line-height: 1.04;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 12px;
  font-size: 22px;
}

p {
  color: var(--muted);
  line-height: 1.7;
}

.hero-copy {
  max-width: 650px;
  color: rgba(255, 255, 255, 0.82);
  font-size: 20px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 34px;
}

.button {
  border: 0;
  cursor: pointer;
}

.button.primary {
  color: var(--white);
  background: var(--teal);
}

.button.secondary {
  color: var(--white);
  border: 1px solid rgba(255, 255, 255, 0.42);
}

.metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
}

.metrics div {
  padding: 34px clamp(18px, 5vw, 64px);
  background: var(--white);
}

.metrics strong {
  display: block;
  margin-bottom: 6px;
  font-size: 34px;
}

.metrics span {
  color: var(--muted);
  font-size: 14px;
}

.section,
.platform,
.contact {
  padding: clamp(72px, 9vw, 118px) clamp(18px, 6vw, 76px);
}

.intro {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 36px;
  background: var(--paper);
}

.intro p,
.platform-copy p,
.contact p {
  max-width: 760px;
  font-size: 18px;
}

.contact-info {
  margin-top: 28px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.contact-info p {
  margin-bottom: 10px;
  font-size: 16px;
}

.contact-info strong {
  color: var(--ink);
}

.section-heading {
  max-width: 760px;
  margin-bottom: 34px;
}

.service-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

.service-card,
.work-list article {
  min-height: 250px;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.icon {
  display: inline-flex;
  margin-bottom: 34px;
  color: var(--teal);
  font-weight: 800;
}

.platform {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(320px, 1.1fr);
  gap: 48px;
  color: var(--white);
  background: #17212b;
}

.platform p {
  color: rgba(255, 255, 255, 0.72);
}

.timeline {
  display: grid;
  gap: 14px;
}

.timeline div {
  padding: 26px;
  border-left: 4px solid var(--green);
  background: rgba(255, 255, 255, 0.07);
}

.timeline span {
  display: block;
  margin-bottom: 8px;
  color: var(--white);
  font-weight: 800;
}

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

.contact {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(320px, 0.75fr);
  gap: 48px;
  background: var(--white);
}

.contact-form {
  display: grid;
  gap: 16px;
}

label {
  display: grid;
  gap: 8px;
  color: var(--ink);
  font-size: 14px;
  font-weight: 700;
}

input,
textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 14px 15px;
  font: inherit;
  background: var(--paper);
}

textarea {
  resize: vertical;
}

.form-note {
  min-height: 24px;
  margin: 0;
  color: var(--teal);
  font-size: 14px;
  font-weight: 700;
}

.site-footer {
  padding: 28px clamp(18px, 6vw, 76px);
  color: rgba(255, 255, 255, 0.7);
  background: #10161d;
}

.footer-links,
.footer-bottom {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-links {
  margin-bottom: 18px;
  padding-bottom: 18px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
  font-size: 14px;
}

.footer-links span {
  color: rgba(255, 255, 255, 0.9);
  font-weight: 700;
}

.footer-bottom {
  justify-content: space-between;
}

@media (max-width: 900px) {
  .nav-links {
    display: none;
  }

  .hero {
    min-height: 86vh;
  }

  .metrics,
  .service-grid,
  .work-list,
  .intro,
  .platform,
  .contact {
    grid-template-columns: 1fr;
  }

  .service-card,
  .work-list article {
    min-height: auto;
  }
}

@media (max-width: 560px) {
  .site-header {
    padding: 14px 16px;
  }

  .brand span:last-child {
    max-width: 126px;
    white-space: normal;
    line-height: 1.05;
  }

  .header-action {
    padding: 0 12px;
    font-size: 13px;
  }

  .hero-content {
    width: calc(100% - 32px);
    margin-left: 16px;
  }

  .hero-copy {
    font-size: 17px;
  }

  .metrics div,
  .section,
  .platform,
  .contact {
    padding-left: 16px;
    padding-right: 16px;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}