:root {
 --width-target: calc(100vw / 6);
 --height-target: calc(100vh / 3);
 --size: min(var(--width-target), var(--height-target));
 --margin-vertical: calc((100vh - var(--size) * 2) / 2);
 --margin-horizontal: calc((100vw - var(--size) * 5) / 2);
}

* {
  margin: 0;
  padding: 0;
}

html {
  background-color: black;
  color: white;
  overflow: hidden;
  text-align: center;
  font-family: monospace;
  font-size: var(--size);
  line-height: var(--size);
}

a {
  color: white;
  text-decoration: none;
}

a:hover {
  text-shadow: 0 0 5px #fff;
}

body {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin: var(--margin-vertical) var(--margin-horizontal);
}

body > * {
  width: var(--size);
}

body > div {
  height: var(--size);
  text-shadow: 0 0 5px #fff;
}

body > a:nth-child(n+5) {
  align-items: center;
  display: flex;
  font-size: calc(var(--size) / 9);
  height: calc(var(--size) / 2);
  justify-content: center;
  line-height: calc(var(--size) / 9);
}

/* just is an isogram */
#j:after       { content: 'j'; }
#j:hover:after { content: ':'; }
#u:after       { content: 'u'; }
#u:hover:after { content: '~'; }
#s:after       { content: 's'; }
#s:hover:after { content: '$'; }
#t:after       { content: 't'; }
#t:hover:after { content: '='; }