body {
  font-family: Verdana, Geneva, sans-serif;
}

.content {
  max-width: 900px;
  margin: 0 auto;
}

h1 {
  font-size: 40px;
  font-weight: bold;
  margin: 20px 0px 0px 20px;
}

h2 {
  font-size: 30px;
  font-weight: bold;
  margin: 10px 0px 10px 20px;
  color: #999;
}

h3 {
  font-size: 20px;
  margin: 20px 0px 0px 20px;
}

h4 {font-size: 15px;
  margin: 20px 0px 0px 20px;
color: #999}


iframe {

  float: middle;
  margin: 0px 0px 20px 0px;
}

.intro-image {
  margin-right: 10px;
  margin-bottom: 20px;
  margin-top: 150px;
    max-width:35%;
  max-height:35%;
}

.centered-image {
  display: block;
  margin-right: auto;
  margin-left: auto;
  margin-bottom: 20px;
  max-width:100%;
  max-height:50%;
}

.intro-body {
  text-align: justify;
  display: inline-block;
  vertical-align: top;
  width: 60%;
}

.chapter {
  text-align: center;
}

.chapter-left {
    border-top: 4px solid #000;
  text-align: left;
  margin: 0px 0px 0px 20px;

}



p {
  font-size: 16px;
  line-height: 20px;
  margin-bottom: 20px;
}

.top {
    width: 100%;
    background: linear-gradient(#999, white)
    }