:root {
  --ink: #142a38;
  --muted: #5d6972;
  --line: #dde4e8;
  --paper: #f7f7f2;
  --white: #ffffff;
  --teal: #1f9d8a;
  --gold: #c9a24b;
  --red: #d95d4f;
  --blue: #4b7ba8;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Microsoft YaHei", "PingFang SC", "Segoe UI", Arial, sans-serif;
  line-height: 1.6;
}

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: 24px;
  height: 72px;
  padding: 0 clamp(20px, 5vw, 72px);
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid rgba(221, 228, 232, 0.9);
  backdrop-filter: blur(14px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  min-width: 120px;
  font-weight: 800;
  font-size: 20px;
}

.brand img {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  border: 1px solid var(--line);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2.4vw, 30px);
  color: var(--muted);
  font-size: 15px;
  white-space: nowrap;
}

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

.hero {
  position: relative;
  isolation: isolate;
  display: flex;
  align-items: center;
  min-height: clamp(560px, 82svh, 760px);
  padding: 72px clamp(20px, 7vw, 96px);
  overflow: hidden;
  background-image: url("/assets/app-hero.png");
  background-position: center;
  background-size: cover;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background: rgba(247, 247, 242, 0.72);
}

.hero-content {
  width: min(650px, 100%);
}

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

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

h1 {
  margin-bottom: 18px;
  font-size: clamp(56px, 8vw, 104px);
  line-height: 1;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 14px;
  font-size: clamp(28px, 4vw, 48px);
  line-height: 1.16;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 10px;
  font-size: 22px;
  line-height: 1.28;
  letter-spacing: 0;
}

.hero-copy {
  width: min(560px, 100%);
  margin-bottom: 30px;
  color: #314655;
  font-size: clamp(17px, 2.4vw, 22px);
}

.hero-actions,
.download-inner {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 22px;
  border-radius: 6px;
  border: 1px solid transparent;
  font-weight: 800;
  font-size: 16px;
}

.button.primary {
  color: var(--white);
  background: var(--ink);
  box-shadow: 0 14px 30px rgba(20, 42, 56, 0.18);
}

.button.secondary {
  color: var(--ink);
  background: rgba(255, 255, 255, 0.86);
  border-color: var(--line);
}

.button:hover {
  transform: translateY(-1px);
}

.metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  width: min(1180px, calc(100% - 40px));
  margin: -52px auto 0;
  position: relative;
  z-index: 5;
}

.metric {
  min-height: 118px;
  padding: 24px;
  border-radius: 8px;
  background: var(--white);
  border: 1px solid var(--line);
  box-shadow: 0 18px 40px rgba(20, 42, 56, 0.08);
}

.metric strong {
  display: block;
  margin-bottom: 8px;
  font-size: clamp(24px, 3vw, 38px);
  line-height: 1;
}

.metric span {
  color: var(--muted);
}

.section {
  padding: clamp(72px, 10vw, 116px) clamp(20px, 6vw, 80px);
}

.section-alt {
  background: var(--white);
}

.section-heading {
  width: min(840px, 100%);
  margin: 0 auto 38px;
  text-align: center;
}

.section-heading p:last-child {
  color: var(--muted);
  font-size: 18px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 18px;
  width: min(1180px, 100%);
  margin: 0 auto;
}

.feature-card {
  min-height: 286px;
  padding: 26px;
  border-radius: 8px;
  background: var(--white);
  border: 1px solid var(--line);
}

.feature-card p,
.scene-item p,
.security p,
.download p {
  color: var(--muted);
}

.feature-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  margin-bottom: 22px;
  color: var(--white);
  border-radius: 8px;
  font-weight: 800;
}

.feature-mark.teal {
  background: var(--teal);
}

.feature-mark.gold {
  background: var(--gold);
}

.feature-mark.red {
  background: var(--red);
}

.feature-mark.blue {
  background: var(--blue);
}

.scene-list {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  width: min(1180px, 100%);
  margin: 0 auto;
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.scene-item {
  min-height: 190px;
  padding: 28px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.security {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(300px, 0.8fr);
  gap: 42px;
  align-items: center;
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto;
  padding-left: 0;
  padding-right: 0;
}

.security-list {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.security-list li {
  padding: 18px 20px;
  border-radius: 8px;
  background: var(--white);
  border: 1px solid var(--line);
  font-weight: 700;
}

.download {
  padding: clamp(72px, 10vw, 108px) 20px;
  background: #173140;
  color: var(--white);
}

.download-inner {
  width: min(980px, 100%);
  margin: 0 auto;
  justify-content: space-between;
}

.download-inner h2,
.download-inner p,
.download-inner .eyebrow {
  width: min(620px, 100%);
}

.download-inner p {
  color: rgba(255, 255, 255, 0.78);
}

.download .button.primary {
  background: var(--gold);
  color: #1d2630;
  box-shadow: none;
}

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  padding: 28px clamp(20px, 5vw, 72px);
  color: var(--muted);
  background: var(--white);
  border-top: 1px solid var(--line);
}

@media (max-width: 980px) {
  .nav-links {
    display: none;
  }

  .hero {
    align-items: flex-start;
    min-height: 700px;
    padding-top: 70px;
    background-position: 72% center;
  }

  .hero::before {
    background: rgba(247, 247, 242, 0.9);
  }

  .metrics,
  .feature-grid,
  .scene-list,
  .security {
    grid-template-columns: 1fr;
  }

  .metrics {
    margin-top: 18px;
  }

  .feature-card,
  .scene-item {
    min-height: auto;
  }

  .security {
    width: min(100% - 40px, 1180px);
  }
}

@media (max-width: 560px) {
  .site-header {
    height: 64px;
    padding: 0 16px;
  }

  .brand {
    font-size: 18px;
  }

  .hero {
    min-height: 650px;
    padding: 54px 18px;
    background-position: 78% center;
  }

  h1 {
    font-size: 56px;
  }

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

  .hero-actions,
  .download-inner {
    align-items: stretch;
    flex-direction: column;
  }

  .button {
    width: 100%;
  }

  .section {
    padding-left: 18px;
    padding-right: 18px;
  }

  .site-footer {
    flex-direction: column;
  }
}