* {
  box-sizing: border-box;
}

html {
  font-size: 16px;
}

body {
  font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", 'DejaVu Sans Mono', ui-monospace, monospace;
  background-color: #f6f6f6;
}

main {
  margin: 15px;
}

.interactive-label {
  font-size: 1.25rem;
  font-weight: bold;
}

.interactive-result {
  background-color: #e9e9e9;
  color: #1640d6;
  padding: 8px 4px;
}

input[type="text"],
.interactive-result {
  font-size: 1.25rem;
}

input[type="text"] {
  padding: 4px;
  width: 100%;
  font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", 'DejaVu Sans Mono', ui-monospace, monospace;
}

main {
  max-width: 1024px;
}

header {
  text-transform: uppercase;
  display: flex;
  align-items: center;
}

header>pre {
  padding-bottom: 1rem;
}

header>*,
header>nav>a {
  padding-right: 20px;
}

footer {
  padding: 20px 0;
}

header pre,
.domain-name {
  font-weight: bold;
}

.table-of-contents>a {
  display: block;
}

.banner {
  padding-bottom: 20px;
  flex-wrap: wrap;
}

.xmas {
  background-image: url("./media/xmas2.gif");
  background-repeat: repeat-x;
  background-size: contain;
  width: 100%;
  height: 100px;
}

.warning {
  color: rgb(167, 0, 0);
}

code {
  background-color: #e9e9e9;
  color: #1640d6;
  font-weight: bold;
  text-align: center;
}


h2 {
  display: flex;
}

h2 a {
  margin-right: 10px;
}

.domain-name {
  border-right: 2px solid black;
  margin-right: 20px;
}

@media (max-width: 680px) {
  .banner {
    flex-direction: column;
    width: 100%;
    align-items: center;
  }

  header>* {
    display: flex;
    flex-direction: column;
  }

  header>nav>a {
    padding: 4px 0;
    padding-right: 0px;
  }
}

@media (max-width: 1024px) {
  h1 {
    text-align: center;
  }

  .banner {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
  }

  .banner img {
    margin: 10px;
  }

  header {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  header>pre {
    padding-bottom: 10px;
  }

  .domain-name {
    padding-bottom: 20px;
    margin-right: 0;
    border-right: 0;
  }

  footer {
    text-align: center;
  }
}