* { box-sizing: border-box; }
html, body { margin: 0; min-height: 100%; }
body {
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #ffffff;
  padding: 16px;
}
img {
  display: block;
  width: 100%;
  max-width: 1200px;
  height: auto;
}