:root {
  --bg: #f6f7fb;
  --fg: #111827;
  --muted: #6b7280;
  --primary: #2563eb;
  --primary-600: #1d4ed8;
  --border: #e5e7eb;
  --card: #ffffff;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--fg);
  padding: 24px;
}

.card {
  max-width: 680px;
  margin: 0 auto;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 20px;
  box-shadow: 0 6px 20px rgba(0,0,0,0.05);
}

h1 {
  margin-top: 0;
  font-size: 1.4rem;
}

label {
  display: block;
  margin-top: 12px;
  font-weight: 600;
}

select, input {
  width: 100%;
  padding: 10px 12px;
  margin-top: 6px;
  border: 1px solid var(--border);
  border-radius: 10px;
  font-size: 1rem;
  background: #fff;
}

.hint {
  display: block;
  color: var(--muted);
  margin-top: 6px;
}

.grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

@media (min-width: 720px) {
  .grid { grid-template-columns: 1fr 1fr 1fr; }
}

.actions {
  display: flex;
  gap: 10px;
  margin-top: 16px;
  flex-wrap: wrap;
}

button {
  appearance: none;
  border: none;
  border-radius: 10px;
  background: var(--primary);
  color: white;
  padding: 10px 14px;
  font-weight: 600;
  cursor: pointer;
}

.actions, 
#btnIOS, 
#btnAndroid {
  margin-top: 30px;
}