body {
  font-family: -apple-system, system-ui, sans-serif;
  margin: 0;
  padding: calc(16px + env(safe-area-inset-top)) 16px calc(16px + env(safe-area-inset-bottom));
  background: #fff;
  color: #111;
}
h1 { font-size: 20px; margin: 0 0 8px; }
p { font-size: 14px; line-height: 1.4; }
button { font: inherit; width: 100%; padding: 14px 18px; border: 0; border-radius: 12px; background: #111; color: #fff; }
button:disabled { opacity: .4; }
pre { white-space: pre-wrap; word-break: break-word; font-size: 12px; background: #f4f4f4; padding: 12px; border-radius: 8px; }