:root {
  --ink: #173237;
  --muted: #5d6f73;
  --line: #dce8e6;
  --soft: #eef7f6;
  --teal: #0f8f84;
  --deep: #06343d;
  --white: #fff;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: #fff;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  min-height: 76px;
  padding: 14px max(32px, calc((100vw - 1160px) / 2));
  border-bottom: 1px solid rgba(220, 232, 230, .8);
  background: rgba(255, 255, 255, .96);
}

.brand img {
  display: block;
  width: 280px;
  max-width: 52vw;
  height: auto;
}

.nav {
  display: flex;
  gap: 28px;
  color: #435a5f;
  font-size: 15px;
  white-space: nowrap;
}

.nav a:hover {
  color: var(--teal);
}

.hero {
  min-height: 500px;
  color: var(--white);
  background:
    linear-gradient(90deg, rgba(0, 28, 39, .92) 0%, rgba(0, 48, 58, .72) 43%, rgba(0, 86, 93, .2) 100%),
    url("background.png") center / cover no-repeat;
}

.hero-inner {
  width: min(1160px, calc(100% - 64px));
  margin: 0 auto;
  padding: 112px 0 96px;
}

.kicker {
  margin: 0 0 14px;
  color: var(--teal);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.hero .kicker {
  color: #7de8d8;
}

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

h1 {
  margin-bottom: 10px;
  font-size: clamp(48px, 6vw, 72px);
  line-height: 1.1;
}

.subtitle {
  margin-bottom: 30px;
  color: #b9f3eb;
  font-size: clamp(22px, 2.6vw, 32px);
  line-height: 1.35;
}

.hero-text {
  max-width: 560px;
  margin-bottom: 0;
  color: rgba(255, 255, 255, .86);
  font-size: 17px;
  line-height: 1.95;
}

.section {
  padding: 72px max(32px, calc((100vw - 1160px) / 2));
}

.section-heading {
  margin-bottom: 34px;
  text-align: center;
}

.section-heading h2 {
  position: relative;
  margin-bottom: 0;
  font-size: clamp(28px, 3vw, 38px);
  line-height: 1.25;
}

.section-heading h2::after {
  content: "";
  display: block;
  width: 42px;
  height: 3px;
  margin: 16px auto 0;
  background: var(--teal);
}

.about-text {
  max-width: 850px;
  margin: 0 auto;
  color: var(--muted);
  font-size: 17px;
  line-height: 2;
  text-align: center;
}

.technology {
  border-top: 1px solid var(--line);
}

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

.tech-card {
  min-height: 220px;
  padding: 30px 26px;
  border: 1px solid var(--line);
  background: var(--white);
}

.tech-card span {
  display: grid;
  place-items: center;
  width: 54px;
  height: 54px;
  margin-bottom: 28px;
  border-radius: 50%;
  color: var(--teal);
  font-weight: 800;
  background: #e1f4f1;
}

.tech-card h3 {
  margin-bottom: 12px;
  font-size: 21px;
}

.tech-card p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.8;
}

.application {
  background: var(--soft);
}

.application-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.application-grid p {
  margin: 0;
  padding: 24px 20px;
  border: 1px solid var(--line);
  color: #345157;
  background: var(--white);
  font-size: 16px;
  text-align: center;
}

.vision {
  padding: 72px max(32px, calc((100vw - 1160px) / 2));
  color: var(--white);
  background: linear-gradient(135deg, #07333d, #0b6f68);
  text-align: center;
}

.vision h2 {
  margin-bottom: 18px;
  font-size: clamp(30px, 4vw, 44px);
  line-height: 1.25;
}

.vision p {
  margin-bottom: 0;
  color: rgba(255, 255, 255, .78);
  font-size: 17px;
  line-height: 1.8;
}

.footer {
  display: flex;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
  padding: 26px 20px;
  color: rgba(255, 255, 255, .78);
  background: var(--deep);
  font-size: 14px;
}

.footer a:hover {
  color: var(--white);
  text-decoration: underline;
}

@media (max-width: 980px) {
  .tech-grid,
  .application-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 700px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    gap: 14px;
    padding: 14px 22px;
  }

  .brand img {
    max-width: 78vw;
  }

  .nav {
    width: 100%;
    justify-content: space-between;
    gap: 10px;
    font-size: 14px;
  }

  .hero {
    min-height: auto;
    background-position: 58% center;
  }

  .hero-inner {
    width: min(100% - 44px, 1160px);
    padding: 72px 0 76px;
  }

  .hero-text {
    max-width: 100%;
  }

  .section {
    padding: 58px 22px;
  }

  .tech-grid,
  .application-grid {
    grid-template-columns: 1fr;
  }

  .tech-card {
    min-height: auto;
  }

  .vision {
    padding: 58px 22px;
  }
}