html,
body {
  background-color: black;
  color: chartreuse;
  width: 100%;
  margin: 0;
  font-family: sans-serif;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

img {
  display: block;
  max-width: 100%;
  max-height: 100vh;
  width: auto;
  height: auto;
}