:root {
  --colour_black: #000000;
  --colour_emerald: #32da98;
  --colour_banana: #eeffaa;
  --colour_white: #ffffff;
}

html, body {
  margin: 0;
  padding: 0;

  padding-bottom: 2.5dvh;

  font-family: Monaco, monospace;
  font-size: 10px;
}

*,
*::after,
*::before {
  box-sizing: border-box;
}

h1,
h2,
p,
.code_block,
footer {
  display: block;

  width: fit-content;

  margin: 0;
  margin-bottom: 5em;

  border: 1px solid var(
    --colour_black
  );

  box-shadow: 10px 10px 0 var(
    --colour_black
  );
}

h1,
h2 {
  padding: 0.5em 4em;
}

p {
  padding: 2em;
}

a {
  color: var(
    --colour_emerald
  );

  padding: 0 1em;
}

a.button,
button {
  margin: 1em;
  padding: 0.75em 1.125em;

  background: var(
    --colour_emerald
  );

  box-shadow: none;

  border: 1px solid var(
    --colour_black
  );

  border-radius: 0;

  text-decoration: none;

  cursor: pointer;
}

a.button {
  background: var(
    --colour_banana
  );

  color: var(
    --colour_black
  );
}

#zer0_introduction {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;

  height: 100dvh;
}

#zer0_introduction p {
  margin-bottom: 10em;
}

h2:first-of-type {
  margin-top: 10dvh;
}

h2,
.code_block {
  margin-left: auto;
  margin-right: auto;
}

.code_block {
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
}

.code_block > div {
  padding: 1em;

  border-right: 1px solid var(
    --colour_black
  );

  text-align: center;
}

.code_block > code {
  background: #eeeeee;

  padding: 0.25em 1em;
  margin: 1em;

  border: 1px solid var(
    --colour_black
  );

  white-space: pre;
}

footer {
  margin: auto;
  margin-top: 10dvh;

  padding: 1em;
}

#zer0_border {
  position: fixed;
  top: 0;
  left: 0;
}

#zer0_border::after {
  content: "";

  position: fixed;
  top: 0;
  left: 0;
  right: 0;

  height: 5px;

  background: var(
    --colour_black
  );
}

#zer0_border::before {
  content: "";

  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;

  width: 5px;

  background: var(
    --colour_black
  );
}