body {
  margin: 0;
  background-color: #f8fafc;
  font: 1rem system-ui, sans-serif;
}

/* Center the button vertically and horizontally in the viewport. */
main {
  display: grid;
  min-height: 100vh;
  min-height: 100dvh;
  place-items: center;
}

button {
  padding: 0.85rem 1.4rem;
  border: 0;
  border-radius: 0.75rem;
  background-color: #334155;
  color: #fff;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}

button:focus-visible {
  outline: 3px solid #0f172a;
  outline-offset: 4px;
}