/* Fill the viewport and set the global look */
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
  background: forestgreen;
  color: #fff;
  font-family: Arial, Helvetica, sans-serif;
}

/* Center the headings both ways */
.center {
  min-height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center; /* vertical */
  align-items: center;     /* horizontal */
  text-align: center;
}

h1, h2 {
  font-weight: 700;
  margin: 0.3em 0;
}

/* Mobile: double font size */
@media (max-width: 600px) {
  h1 {
    font-size: 2em; /* Default ~32px; doubled for mobile */
    font-size: calc(2em * 2); /* Safe scaling */
  }
  h2 {
    font-size: 1.5em; /* Default ~24px; doubled for mobile */
    font-size: calc(1.5em * 2);
  }
}