body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  background: #f6f7fb;
}
.card {
  width: min(680px, 92vw);
  background: white;
  border-radius: 16px;
  padding: 28px;
  box-shadow: 0 8px 30px rgba(0,0,0,.08);
}
.btn {
  display: inline-block;
  margin-top: 16px;
  padding: 12px 18px;
  border-radius: 12px;
  text-decoration: none;
  background: #111827;
  color: white;
}