* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { min-height: 100%; width: 100%; }
body {
  min-height: 100vh;
  background: #fff;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  display: grid;
  place-items: center;
  overflow: hidden;
}
.container { text-align: center; padding: 20px; max-width: 800px; width: 100%; }
img { max-width: 100%; height: auto; display: block; margin: 0 auto; }