:root {
  --bg: #F6F8FB;
  --card: #FFFFFF;
  --text: #1E2022;
  --muted: #4A5058;
  --accent: #1D63ED;
  --accent-2: #6C8CFF;
  --accent-hover: #154ec1;
  --on-accent: #FFFFFF;
  --line: #D9DDE3;
  --soft: #EAF1FF;
  --note-bg: #FFF4D6;
  --note-text: #4D3B00;
  --note-border: #E8C868;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #101216;
    --card: #1C1F26;
    --text: #F0F2F5;
    --muted: #B4BAC4;
    --accent: #5B8FF5;
    --accent-2: #8FB0FF;
    --accent-hover: #7aa7ff;
    --on-accent: #0B1220;
    --line: #2C313B;
    --soft: #1A2338;
    --note-bg: #2B240B;
    --note-text: #FFEAA8;
    --note-border: #6B561B;
  }
}

* {
  box-sizing: border-box;
}

html {
  font-size: 20px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background-color: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  line-height: 1.6;
}

main {
  max-width: 680px;
  margin: 0 auto;
  padding: 28px 20px 60px;
}

.hero {
  background: linear-gradient(160deg, var(--soft), var(--card));
  border: 1px solid var(--line);
  border-radius: 28px;
  padding: 36px 24px 28px;
  text-align: center;
}

h1 {
  font-size: 2.6rem;
  font-weight: 800;
  line-height: 1.15;
  margin: 0 0 12px;
  letter-spacing: -0.03em;
}

h2 {
  font-size: 1.4rem;
  font-weight: 700;
  margin: 48px 0 16px;
  line-height: 1.3;
}

p {
  margin: 0 0 16px;
}

.lead {
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--muted);
  margin-bottom: 8px;
}

.download {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 76px;
  padding: 20px 24px;
  margin: 24px 0 12px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: var(--on-accent);
  font-size: 1.4rem;
  font-weight: 800;
  text-align: center;
  text-decoration: none;
  border-radius: 20px;
  box-shadow: 0 8px 22px rgba(29, 99, 237, 0.28);
  transition: transform 0.1s ease, box-shadow 0.15s ease;
}

.download:hover {
  box-shadow: 0 10px 26px rgba(29, 99, 237, 0.4);
}

.download:active {
  transform: scale(0.99);
}

.note {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--muted);
  text-align: center;
  margin: 0;
}

.warn {
  display: none;
  background-color: var(--note-bg);
  color: var(--note-text);
  border: 1px solid var(--note-border);
  padding: 16px 20px;
  border-radius: 16px;
  margin: 20px 0 0;
  font-weight: 600;
  font-size: 0.95rem;
  text-align: left;
}

.features {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 20px;
}

.feature {
  background-color: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 16px 18px;
}

.feature strong {
  display: block;
  font-size: 1rem;
  margin-bottom: 2px;
}

.feature span {
  font-size: 0.85rem;
  color: var(--muted);
  line-height: 1.4;
  display: block;
}

.steps {
  list-style: none;
  padding: 0;
  margin: 0;
}

.steps li {
  background-color: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 18px 20px;
  margin-bottom: 14px;
}

.steps strong {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.1rem;
  color: var(--text);
  margin-bottom: 8px;
}

.steps .num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background-color: var(--accent);
  color: var(--on-accent);
  font-size: 0.95rem;
  font-weight: 800;
}

.steps li > span {
  display: block;
  font-size: 0.95rem;
  color: var(--muted);
  line-height: 1.5;
}

.formats {
  padding-left: 24px;
  margin: 0 0 20px;
}

.formats li {
  margin-bottom: 10px;
  font-size: 1rem;
}

details {
  background-color: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 16px 20px;
  margin-bottom: 14px;
}

details[open] {
  border-color: var(--accent);
}

summary {
  font-weight: 700;
  font-size: 1.05rem;
  cursor: pointer;
  min-height: 48px;
  display: flex;
  align-items: center;
  touch-action: manipulation;
}

details p {
  margin: 12px 0 4px;
  font-size: 0.95rem;
  color: var(--muted);
  line-height: 1.55;
}

details a {
  color: var(--accent);
  text-decoration: underline;
}

.fingerprint {
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 0.8rem;
  word-break: break-all;
  background-color: var(--soft);
  border-radius: 10px;
  padding: 12px 14px;
  color: var(--text);
}

footer {
  margin-top: 50px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 16px 24px;
  margin-top: 12px;
}

.footer-links a {
  color: var(--accent);
  text-decoration: underline;
  min-height: 48px;
  display: inline-flex;
  align-items: center;
}

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

@media (max-width: 480px) {
  html {
    font-size: 19px;
  }
  main {
    padding: 16px 14px 44px;
  }
  .hero {
    padding: 28px 18px 22px;
  }
  .download {
    font-size: 1.25rem;
    min-height: 76px;
  }
}