:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --text: #172033;
  --muted: #627089;
  --line: #dfe7f3;
  --brand: #1469c9;
  --brand-dark: #0d4f9f;
  --teal: #0b9f99;
  --shadow: 0 18px 50px rgba(24, 46, 87, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  -webkit-font-smoothing: antialiased;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  min-width: 320px;
  background: var(--bg);
  color: var(--text);
  font-family: "Noto Sans CJK SC", "Noto Sans SC", "Source Han Sans SC", "WenQuanYi Micro Hei", sans-serif;
  font-size: 15px;
  line-height: 1.65;
}

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

.container {
  width: min(1120px, calc(100% - 40px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  height: 68px;
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid rgba(223, 231, 243, 0.8);
  backdrop-filter: blur(14px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo img {
  display: block;
  width: 150px;
  height: auto;
}

.site-nav a {
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--brand);
  font-size: 14px;
  font-weight: 700;
  background: #ffffff;
}

.hero {
  min-height: 430px;
  display: flex;
  align-items: center;
  color: #ffffff;
  background:
    linear-gradient(135deg, rgba(9, 91, 143, 0.95), rgba(10, 137, 132, 0.92)),
    url("https://www.cailiaoren.com/img/logo.png") center / 280px auto no-repeat;
}

.hero-inner {
  padding: 74px 0 86px;
}

.hero-kicker,
.section-heading p {
  margin: 0 0 8px;
  color: var(--teal);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

.hero-kicker {
  color: rgba(255, 255, 255, 0.78);
}

.hero h1 {
  max-width: 660px;
  margin: 0;
  font-size: clamp(32px, 5.8vw, 56px);
  line-height: 1.12;
  font-weight: 800;
}

.hero-copy {
  max-width: 580px;
  margin: 22px 0 0;
  color: rgba(255, 255, 255, 0.86);
  font-size: 18px;
}

.contact-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.contact-row span {
  padding: 8px 14px;
  border: 1px solid rgba(255, 255, 255, 0.26);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.12);
}

.section {
  padding: 54px 0;
}

.section-download {
  background: var(--surface);
}

.section-heading {
  margin-bottom: 24px;
}

.section-heading h2 {
  margin: 0;
  font-size: 28px;
  line-height: 1.3;
}

.download-actions {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 260px));
  gap: 16px;
}

.download-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 54px;
  border: 0;
  border-radius: 8px;
  color: #ffffff;
  cursor: pointer;
  font: inherit;
  font-size: 17px;
  font-weight: 700;
  box-shadow: var(--shadow);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.download-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 22px 54px rgba(24, 46, 87, 0.16);
}

.download-button:focus-visible {
  outline: 3px solid rgba(20, 105, 201, 0.25);
  outline-offset: 3px;
}

.download-button.android {
  background: linear-gradient(135deg, var(--teal), #10b981);
}

.download-button.ios {
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
}

.section-history {
  background: var(--bg);
}

.timeline {
  position: relative;
  display: grid;
  gap: 18px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.timeline::before {
  content: "";
  position: absolute;
  top: 8px;
  bottom: 8px;
  left: 24px;
  width: 2px;
  background: var(--line);
}

.timeline li {
  position: relative;
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 22px;
  padding: 20px 24px 20px 72px;
  background: var(--surface);
  border: 1px solid rgba(223, 231, 243, 0.8);
  border-radius: 8px;
  box-shadow: 0 12px 36px rgba(24, 46, 87, 0.06);
}

.timeline li::before {
  content: "";
  position: absolute;
  top: 28px;
  left: 18px;
  width: 12px;
  height: 12px;
  border: 3px solid var(--surface);
  border-radius: 50%;
  background: var(--brand);
  box-shadow: 0 0 0 2px rgba(20, 105, 201, 0.2);
}

.timeline time {
  grid-column: 1;
  color: var(--brand);
  font-size: 20px;
  font-weight: 800;
  line-height: 1.3;
}

.timeline p {
  grid-column: 2;
  margin: 0 0 8px;
  color: var(--muted);
}

.timeline p:last-child {
  margin-bottom: 0;
}

.site-footer {
  padding: 18px 0;
  background: #202733;
  color: rgba(255, 255, 255, 0.62);
  font-size: 13px;
}

.site-footer p {
  margin: 0;
}

@media (max-width: 720px) {
  body {
    font-size: 14px;
    line-height: 1.6;
  }

  .container {
    width: min(100% - 24px, 1120px);
  }

  .site-header {
    height: 56px;
  }

  .logo img {
    width: 116px;
  }

  .site-nav a {
    min-height: 32px;
    padding: 0 10px;
    font-size: 13px;
  }

  .hero {
    min-height: 300px;
    background-size: 190px auto;
  }

  .hero-inner {
    padding: 42px 0 48px;
  }

  .hero-kicker,
  .section-heading p {
    margin-bottom: 6px;
    font-size: 11px;
  }

  .hero h1 {
    max-width: 330px;
    font-size: 28px;
    line-height: 1.22;
  }

  .hero-copy {
    max-width: 330px;
    margin-top: 14px;
    font-size: 14px;
    line-height: 1.65;
  }

  .contact-row {
    display: grid;
    gap: 8px;
    margin-top: 16px;
  }

  .contact-row span {
    width: fit-content;
    max-width: 100%;
    padding: 6px 10px;
    font-size: 13px;
    line-height: 1.4;
  }

  .download-actions {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .section {
    padding: 30px 0;
  }

  .section-heading {
    margin-bottom: 16px;
  }

  .section-heading h2 {
    font-size: 22px;
    line-height: 1.35;
  }

  .download-button {
    min-height: 46px;
    font-size: 15px;
    box-shadow: 0 12px 30px rgba(24, 46, 87, 0.12);
  }

  .timeline {
    gap: 12px;
  }

  .timeline::before {
    left: 17px;
  }

  .timeline li {
    grid-template-columns: 1fr;
    gap: 6px;
    padding: 14px 14px 14px 42px;
  }

  .timeline li::before {
    top: 22px;
    left: 11px;
    width: 10px;
    height: 10px;
  }

  .timeline time {
    font-size: 17px;
    line-height: 1.25;
  }

  .timeline p {
    grid-column: 1;
    margin-bottom: 5px;
    font-size: 13px;
    line-height: 1.65;
  }

  .site-footer {
    padding: 14px 0;
    font-size: 12px;
    line-height: 1.6;
  }
}

@media (max-width: 380px) {
  .hero h1 {
    font-size: 25px;
  }

  .hero {
    min-height: 280px;
  }

  .timeline li {
    padding-right: 12px;
  }
}