body {
  font-family: Times, TimesRoman, serif;
  font-size: 18px;
  background-color: #ccccc0;
  margin: 0;
  padding: 0;
  min-width: 550px;
}

.header {
  background-color: #000;
  padding: 50px 0 20px 0;
}

.title_bar {
  margin: 0 auto;
  width: 615px;
  color: #f44;
  font-family: serif;
  font-weight: 200;
  font-size: 50px;
}

.nav_bar {
  margin: 0 auto;
  padding: 0;
  width: 620px;
}
.nav_bar li {
  list-style: none;
  display: inline-block;
  width: 120px;
}
.nav_bar a:link,
.nav_bar a:hover,
.nav_bar a:visited,
.nav_bar a {
  font-family: Arial, sans-serif;
  font-weight: bold;
  font-size: 15px;
  text-decoration: none;
  color: #fff;
  background-color: inherit;
}
.nav_bar a:hover {
  text-decoration: underline;
}
.nav_bar .material-icons {
  vertical-align: bottom;
  margin-right: 5px;
}

.menu {
  position: absolute;
  top: 170px;
}
.menu ul {
  margin-left: 20px;
  padding: 0;
}
.menu li {
  list-style-type: none;
}
.nav_link,
.nav_link:hover,
.nav_link:active,
.nav_link:visited {
  text-decoration: none;
  background-color: initial;
  position: absolute;
  top: 0px;
}
.nav_link.back {
  left: -50px;
}
.nav_link.forward {
  right: -50px;
}

#ad_bar,
#ad_bar_sideline {
  display: none;
}

.page_text {
  position: relative;
  margin: 40px auto 0 auto;
  width: 550px;
  background-color: white;
  border: solid 1px #aaa;
  border-radius: 20px;
  padding: 20px 40px;
}

.bottom_rule {
  display: none;
}

.question, .remark, .fact, .example {
  font-weight: bold;
  margin-bottom: 12px;
}

.footer {
  text-align: center;
  font-family: sans-serif;
  font-size: 10px;
  color: #a0a0a0;
  margin: 20px 0;
}

.footer .copyright {
  white-space: pre;
}

a:link {
  color: #800000;
  text-decoration: none;
}

a:visited {
  color: #800000;
  text-decoration: none;
}

a:hover {
  background: #FFFF80;
  text-decoration: underline;
}

a:active {
  color: #FF0000;
  background: #FFFF40;
}

h1 {
  font-family: Arial, sans-serif;
  font-size: 24px;
  font-weight: bold;
  color: 808080;
}

h2 {
  font-family: Arial, sans-serif;
  font-size: 20px;
  font-weight: normal;
  color: 606060;
}

h3 {
  font-family: Arial, sans-serif;
  font-size: 16px;
  font-weight: bold;
  color: 404040;
  text-decoration: underline;
}

div.line {
  width: 250px;
  border-top: #808080 dashed 1px;
  margin-left: 150px;
  margin-top: 20px;
  margin-bottom: 20px;
}

div.bigline {
  border-top: #ddd solid 1px;
  margin-top: 20px;
  margin-bottom: 20px;
}