:root {
  --bg: #ffffff;
  --surface: #f3f6fb;
  --text: #1f2937;
  --muted: #5b6474;
  --accent: #1a56db;
  --border: #dbe2ee;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --surface: #1e293b;
    --text: #e5e7eb;
    --muted: #a3adbd;
    --accent: #60a5fa;
    --border: #334155;
  }
}

* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
a { color: var(--accent); }
.wrap { max-width: 1100px; margin: 0 auto; padding: 0 16px; }

header { border-bottom: 1px solid var(--border); }
header .wrap { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.brand { font-weight: 700; color: var(--text); text-decoration: none; }
nav a { margin-left: 20px; text-decoration: none; }

.hero { padding: 48px 0 24px; }
.hero h1 { font-size: clamp(28px, 5vw, 44px); line-height: 1.15; margin: 0 0 12px; }
.hero p { color: var(--muted); max-width: 720px; margin: 0; }

.app {
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  background: var(--surface);
}
.app iframe { display: block; width: 100%; height: 1400px; border: 0; }
.app-missing { padding: 48px 24px; margin: 0; text-align: center; color: var(--muted); }
.app-note { font-size: 14px; color: var(--muted); margin: 8px 0 0; }

section { padding: 40px 0; }
h2 { font-size: 26px; margin: 0 0 16px; }
.steps { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 18px; }
.card h3 { margin: 0 0 6px; font-size: 18px; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }

.faq { border-bottom: 1px solid var(--border); padding: 12px 0; }
.faq summary { cursor: pointer; font-weight: 600; }
.faq p { margin: 8px 0 0; color: var(--muted); }

.warning { border-left: 4px solid var(--accent); padding: 4px 0 4px 16px; }

footer { border-top: 1px solid var(--border); padding: 24px 0; font-size: 14px; color: var(--muted); }
footer .wrap > a { margin-right: 16px; }

.page { max-width: 760px; padding: 40px 16px; }

@media (max-width: 600px) {
  nav a { margin-left: 12px; font-size: 15px; }
  .app iframe { height: 1800px; }
}