/* Full height! */
body {
  height: 100vh;
}

img {
  margin: 0 calc(50% - 50vw);
  width: 100vw;
}

/* layout */
body {
  display: flex;
  flex-direction: column;
  padding: 0;
}

h1,
footer {
  background: papayawhip;
  flex: none;
}

h1,
h2 {
  font-size: 1em;
  margin: 0;
}

main {
  flex: 1;
  overflow: auto;
}

article {
  border-inline: medium dotted;
  margin-inline: auto;
  max-width: 45ch;
  padding-inline: 0.5em;
}

h1,
main,
footer {
  padding: 0.5rem;
}

footer {
  font-size: 0.5em;
}

img {
  max-width: initial;
}