:root {
  color-scheme: light dark;
  --page: #f3f7fc;
  --surface: #fbfdff;
  --surface-soft: #eaf2fc;
  --ink: #10213b;
  --muted: #56677d;
  --line: #ccd8e8;
  --accent: #0b5bd3;
  --accent-hover: #0849ae;
  --accent-ink: #f7fbff;
  --shadow: 0 22px 60px rgba(18, 52, 94, 0.14);
  --radius-large: 28px;
  --radius-medium: 18px;
  --radius-small: 12px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --page: #081322;
    --surface: #0e1c2f;
    --surface-soft: #142944;
    --ink: #edf5ff;
    --muted: #a9bad0;
    --line: #2a405d;
    --accent: #4b91f1;
    --accent-hover: #6ca7f7;
    --accent-ink: #071527;
    --shadow: 0 22px 64px rgba(1, 7, 16, 0.38);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-width: 320px;
  min-height: 100dvh;
  background: var(--page);
  color: var(--ink);
  font-family: "Aptos", "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.6;
}

a { color: inherit; }

.site-header,
main,
footer {
  width: min(1180px, calc(100% - 48px));
  margin-inline: auto;
}

.site-header {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
  font-size: 17px;
  font-weight: 760;
  text-decoration: none;
}

.brand img { border-radius: var(--radius-small); }

.web-link,
.text-link {
  color: var(--accent);
  font-weight: 700;
  text-decoration-thickness: 1px;
  text-underline-offset: 5px;
}

.hero {
  min-height: min(720px, calc(100dvh - 104px));
  display: grid;
  grid-template-columns: minmax(0, 0.86fr) minmax(520px, 1.14fr);
  align-items: center;
  gap: 52px;
  padding: 36px 0 72px;
}

.hero-copy { max-width: 560px; }

.eyebrow {
  margin: 0 0 12px;
  color: var(--accent);
  font-size: 14px;
  font-weight: 760;
  letter-spacing: 0.12em;
}

h1,
h2,
h3,
p { text-wrap: pretty; }

h1 {
  margin: 0;
  max-width: 10em;
  font-size: clamp(42px, 5.1vw, 72px);
  line-height: 1.08;
  letter-spacing: -0.035em;
}

.hero-text {
  max-width: 25em;
  margin: 24px 0 0;
  color: var(--muted);
  font-size: clamp(18px, 2vw, 21px);
}

.hero-actions {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.button {
  min-height: 50px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid transparent;
  border-radius: var(--radius-small);
  padding: 12px 20px;
  font-weight: 760;
  line-height: 1.2;
  text-align: center;
  text-decoration: none;
  white-space: nowrap;
  transition: transform 180ms ease, background-color 180ms ease, border-color 180ms ease;
}

.button:hover { transform: translateY(-2px); }

.button-primary {
  background: var(--accent);
  color: var(--accent-ink);
}

.button-primary:hover { background: var(--accent-hover); }

.button-secondary {
  border-color: var(--line);
  background: var(--surface);
  color: var(--ink);
}

.button:focus-visible,
a:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 4px;
}

.hero-visual {
  margin: 0;
  overflow: hidden;
  border: 1px solid rgba(116, 151, 198, 0.28);
  border-radius: var(--radius-large);
  background: #07162c;
  box-shadow: var(--shadow);
}

.hero-visual img {
  width: 100%;
  height: auto;
  display: block;
}

.download-section,
.guide-section { padding: 92px 0; }

.section-heading {
  max-width: 700px;
  margin-bottom: 34px;
}

h2 {
  margin: 0;
  font-size: clamp(30px, 3.6vw, 48px);
  line-height: 1.16;
  letter-spacing: -0.025em;
}

.section-heading > p:last-child,
.guide-intro > p:last-child,
.ios-note p {
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 17px;
}

.download-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.28fr) minmax(330px, 0.72fr);
  gap: 22px;
  align-items: stretch;
}

.download-card {
  border: 1px solid var(--line);
  border-radius: var(--radius-large);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.android-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-content: start;
  gap: 18px 32px;
  padding: 38px;
}

.platform-heading {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  gap: 16px;
}

.platform-mark {
  color: var(--accent);
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0.08em;
}

.download-card h3 {
  margin: 0;
  font-size: 28px;
  line-height: 1.2;
}

.download-card p {
  grid-column: 1;
  margin: 0;
  max-width: 42em;
  color: var(--muted);
}

.android-card > .button {
  grid-column: 2;
  grid-row: 2 / span 2;
  align-self: center;
}

.facts {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: 0.7fr 0.7fr 1.6fr;
  gap: 1px;
  margin: 12px 0 0;
  overflow: hidden;
  border-radius: var(--radius-medium);
  background: var(--line);
}

.facts div {
  padding: 16px 18px;
  background: var(--surface-soft);
}

.facts dt {
  color: var(--muted);
  font-size: 13px;
}

.facts dd {
  margin: 4px 0 0;
  font-weight: 760;
  overflow-wrap: anywhere;
}

.iphone-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 18px;
  padding: 32px;
}

.platform-icon {
  border-radius: var(--radius-medium);
  box-shadow: 0 12px 30px rgba(11, 91, 211, 0.22);
}

.iphone-card .button { width: 100%; }

.guide-section {
  display: grid;
  grid-template-columns: minmax(250px, 0.62fr) minmax(0, 1.38fr);
  gap: 64px;
  align-items: start;
}

.guide-intro { position: sticky; top: 24px; }

.guide-columns {
  display: grid;
  gap: 24px;
}

.guide-columns article {
  border-left: 4px solid var(--accent);
  border-radius: 0 var(--radius-medium) var(--radius-medium) 0;
  padding: 28px 30px;
  background: var(--surface);
}

.guide-columns h3 {
  margin: 0 0 20px;
  font-size: 24px;
}

.guide-columns ol {
  display: grid;
  gap: 18px;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: guide;
}

.guide-columns li {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 18px;
  counter-increment: guide;
}

.guide-columns strong::before {
  content: counter(guide) ". ";
  color: var(--accent);
}

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

.ios-note {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 32px;
  align-items: center;
  margin-bottom: 96px;
  border-radius: var(--radius-large);
  padding: 34px 38px;
  background: var(--surface-soft);
}

.ios-note h2 { font-size: 28px; }

footer {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 26px 0 max(30px, env(safe-area-inset-bottom));
  border-top: 1px solid var(--line);
  color: var(--muted);
}

footer a { color: var(--accent); }

@media (max-width: 900px) {
  .site-header,
  main,
  footer { width: min(100% - 32px, 720px); }

  .hero {
    min-height: auto;
    grid-template-columns: 1fr;
    gap: 34px;
    padding: 36px 0 56px;
  }

  .hero-copy { max-width: 640px; }

  .hero-visual { order: 2; }

  .download-grid,
  .guide-section { grid-template-columns: 1fr; }

  .guide-section { gap: 32px; }

  .guide-intro { position: static; }
}

@media (max-width: 620px) {
  .site-header { min-height: 68px; }
  .brand span { display: none; }
  .web-link { font-size: 14px; }
  h1 { font-size: clamp(38px, 12vw, 52px); }
  .hero-actions,
  .hero-actions .button { width: 100%; }
  .download-section,
  .guide-section { padding: 68px 0; }
  .download-grid { grid-template-columns: minmax(0, 1fr); }
  .android-card { grid-template-columns: minmax(0, 1fr); padding: 28px 22px; }
  .android-card > .button { grid-column: 1; grid-row: auto; width: 100%; }
  .facts { grid-template-columns: 1fr; }
  .iphone-card { padding: 28px 22px; }
  .guide-columns article { padding: 24px 20px; }
  .guide-columns li { grid-template-columns: 1fr; gap: 4px; }
  .ios-note { grid-template-columns: 1fr; padding: 28px 22px; }
  .ios-note .button { width: 100%; }
  footer { flex-direction: column; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .button { transition: none; }
  .button:hover { transform: none; }
}