html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background-color: #f0f0f0;
}
.container {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
}
.responsive-img {
  max-width: 100%;
  max-height: 100%;
  height: auto;
  width: auto;
}