body {
  font-family: sans-serif;

  margin-left: auto;
  margin-right: auto;
  max-width: 600px;
}


/* headings */

th, h1, h2, h3, h4, h5, h6, .title {
  font-family: serif;
}

h1, h2, h3, h4, h5, h6 {
  margin-top: 3em;
  border-bottom: thin solid silver;
}


/* table of contents */

#menu {
  position: fixed;
  left: 0px;
  top: 0px;

  background-color: ghostwhite;
  border-bottom: thin solid lavender;
  width: 100%;

  text-align: center;
}


/* admonitions */

.admonition {
  border: thin solid steelblue;
  background-color: aliceblue;
  padding: 1em;
  margin-bottom: 1em;
  margin-top: 1em;

  min-height: 170px;
}

.admonition img {
  margin-right: 2em;
}


/* source code */

tt {
  background-color: #cfc;
}

pre, blockquote .code {
  padding: 1em;
  line-height: normal;
  overflow: auto;
  display: block;
}

pre {
  border: thin solid darkgray;
  background-color: whitesmoke;
}

.code {
  border: thin solid darkkhaki;
  background-color: ivory;
}


/* tables */

th, td {
  padding: 1em;
  border: thin solid silver;
}

th {
  background-color: whitesmoke;
}


/* formal blocks; see http://www.sagehill.net/docbookxsl/FormalTitles.html */

.formal {
  margin: 1em;
}

.title {
  display: block;
  font-size: large;
}

.formal .title {
  text-align: center
}


  /* center-align any tables and images */

  .formal table, .formal img {
    margin-left: auto;
    margin-right: auto;
  }

  .formal img {
    display: block;
  }


/* misc. */

a img {
  border: none;
}

em, strong {
  font-family: serif;
}

.formal .title {
  margin-top: 3em;
}