html, body { height: 100%; }

body {
  display: grid;
  place-items: center;          /* centers horizontally + vertically */
  min-height: 100svh;           /* better on mobile than 100vh */
  margin: 0;
  background: #fff;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI','Roboto','Helvetica Neue','Ubuntu',sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Optional wrapper around #checkout */
section {
  display: flex;
  flex-direction: column;
  width: 100%;
  max-width: 480px;             /* keep it reasonable */
  border-radius: 6px;
  background: #fff;
}

/* Let the embedded Checkout size itself */
#checkout {
  width: 100%;
  min-height: 420px;            /* prevents initial collapse */
}

.hidden { display: none; }