:root {
  --paper: #f7f6f3;
  --surface: #ffffff;
  --ink: #1f2320;
  --ink-soft: #5b6560;
  --line: #dfdcd4;
  --accent: #2f6f6a;
  --accent-soft: #e3ece9;
  --accent-ink: #ffffff;
  --serif: 'Spectral', Georgia, serif;
  --sans: 'Source Sans 3', system-ui, sans-serif;
  --shadow: 0 1px 2px rgba(20, 24, 22, 0.04), 0 8px 24px rgba(20, 24, 22, 0.06);
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #171a1c;
    --surface: #1e2124;
    --ink: #e7e9e6;
    --ink-soft: #a6ada8;
    --line: #2d3134;
    --accent: #4fa39a;
    --accent-soft: #223330;
    --accent-ink: #0f1413;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.2), 0 8px 24px rgba(0, 0, 0, 0.3);
  }
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background:
    radial-gradient(circle at top left, color-mix(in srgb, var(--accent-soft) 75%, transparent), transparent 34%),
    radial-gradient(circle at bottom right, color-mix(in srgb, var(--accent-soft) 55%, transparent), transparent 28%),
    var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; }

.wrap {
  width: min(960px, calc(100% - 40px));
  margin: 0 auto;
}

.page {
  padding: 28px 0 72px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 10px 0 22px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  user-select: none;
  -webkit-user-select: none;
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.1rem;
}

.brand svg {
  width: 22px;
  height: 22px;
  color: var(--accent);
}

.back-link {
  color: var(--ink-soft);
  text-decoration: none;
  font-size: 0.95rem;
}

.hero {
  padding: 34px;
  border: 1px solid var(--line);
  border-radius: 24px;
  background: color-mix(in srgb, var(--surface) 90%, transparent);
  box-shadow: var(--shadow);
}

.eyebrow {
  display: inline-block;
  margin-bottom: 14px;
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.hero h1 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2rem, 4vw, 3rem);
  line-height: 1.08;
}

.hero p {
  max-width: 56ch;
  color: var(--ink-soft);
  font-size: 1.04rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 18px;
  border-radius: 10px;
  border: 1px solid transparent;
  text-decoration: none;
  font-weight: 700;
}

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

.btn-secondary {
  border-color: var(--line);
  background: transparent;
  color: var(--ink);
}

.btn.download-pending,
.btn.download-pending:hover {
  cursor: wait;
  pointer-events: auto;
  opacity: 0.78;
}

.download-spinner {
  width: 1em;
  height: 1em;
  flex: 0 0 auto;
  border: 2px solid currentColor;
  border-right-color: transparent;
  border-radius: 50%;
  animation: download-spin 0.75s linear infinite;
}

.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

@keyframes download-spin { to { transform: rotate(360deg); } }

@media (prefers-reduced-motion: reduce) {
  .download-spinner { animation-duration: 1.5s; }
}

.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
  margin-top: 24px;
}

.card {
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.card h2,
.card h3 {
  margin: 0 0 10px;
  font-family: var(--serif);
}

.card p,
.card li {
  color: var(--ink-soft);
}

.steps,
.files {
  margin: 14px 0 0;
  padding-left: 18px;
}

.files code {
  font-size: 0.92rem;
}

.note {
  margin-top: 24px;
  padding: 16px 18px;
  border-left: 4px solid var(--accent);
  border-radius: 12px;
  background: var(--accent-soft);
}

.platform-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-top: 24px;
}

.platform-link {
  display: block;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--surface);
  box-shadow: var(--shadow);
  text-decoration: none;
}

.platform-link strong {
  display: block;
  margin-bottom: 8px;
  font-size: 1.05rem;
}

.platform-link span {
  color: var(--ink-soft);
}

@media (max-width: 860px) {
  .grid,
  .platform-list {
    grid-template-columns: 1fr;
  }

  .hero {
    padding: 24px;
  }

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