:root {
  --bg: #f5f6f8;
  --card: #ffffff;
  --text: #1a1c20;
  --muted: #6b7280;
  --border: #e5e7eb;
  --accent: #2f6bff;
  --accent-2: #1d4ed8;
  --shadow: 0 1px 2px rgba(16, 24, 40, .05), 0 8px 24px rgba(16, 24, 40, .05);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15171b;
    --card: #1f2227;
    --text: #e8eaee;
    --muted: #9aa3b2;
    --border: #2c3038;
    --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 8px 24px rgba(0, 0, 0, .25);
  }
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Segoe UI", "Microsoft YaHei", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.7;
}

.wrap {
  max-width: 680px;
  margin: 0 auto;
  padding: 64px 20px 56px;
}

.hero { text-align: center; margin-bottom: 44px; }

.mark {
  width: 72px;
  height: 72px;
  margin: 0 auto 20px;
  border-radius: 18px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  font-size: 34px;
  line-height: 72px;
  box-shadow: 0 6px 18px rgba(47, 107, 255, .28);
}

.wordmark {
  margin: 0;
  font-size: 34px;
  font-weight: 650;
  letter-spacing: .14em;
  text-indent: .14em;
}

.subtitle {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 15px;
  letter-spacing: .02em;
}

.lede {
  margin: 18px auto 0;
  max-width: 30em;
  color: var(--text);
}

.actions {
  margin-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  transition: transform .15s ease, box-shadow .15s ease, opacity .15s ease;
}

.btn:hover { transform: translateY(-1px); box-shadow: var(--shadow); }

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  border-color: transparent;
  color: #fff;
}

.btn-primary:hover { opacity: .94; }

.btn-sub { font-size: 13px; opacity: .72; font-weight: 400; }

.btn:focus-visible,
a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.version {
  margin: 14px 0 0;
  min-height: 1.4em;
  color: var(--muted);
  font-size: 13px;
}

.note {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 22px 24px;
  margin-bottom: 16px;
  box-shadow: var(--shadow);
}

.card h2 {
  margin: 0 0 8px;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: .08em;
  color: var(--muted);
}

.card p { margin: 0; }

.card strong { font-weight: 600; }

.steps {
  margin: 0;
  padding-left: 1.3em;
}

.steps li { margin: 2px 0; }

.foot {
  margin-top: 40px;
  text-align: center;
  color: var(--muted);
  font-size: 13px;
  letter-spacing: .06em;
}

@media (max-width: 420px) {
  .wrap { padding: 44px 16px 40px; }
  .wordmark { font-size: 28px; }
  .actions { flex-direction: column; }
  .btn { justify-content: center; }
  .card { padding: 18px 18px; }
}