body {
  font-family: 'Arial', sans-serif;
}

.content {
  max-width: 1000px;
  margin: 0 auto;
  border-top: 8px solid #000;
}

h1 {
  font-size: 50px;
  font-weight: bold;
  margin: 20px 0px 0px 20px;
}

h2 {
  font-size: 30px;
  font-weight: bold;
  margin: 5px 0px 10px 20px;
  color: #999;
}


h3{
  font-size: 20px;
  font-weight: bold;
  margin: 5px 0px 10px 0px;
  color: #000;
}

h4{
  font-size: 16px;
  font-weight: bold;
  margin: 5px 0px 10px 0px;
  color: #000;
}


.table-of-contents {
  text-align: center;
  margin: 40px;
}


.chapter {
  text-align: left;
}

.chapter-image {
  margin-right: auto;
  margin-left: auto;
  margin-bottom: 20px;
  width: 70%;
  height: auto;
}
.chapter-image-inst {
  margin-right: 20px;
  margin-bottom: 20px;
  width: 30%;
  height: auto;
}

.chapter-image-exp {
  margin-right: 20px;
  margin-bottom: 20px;
  width: 45%;
  height: auto;
}

.chapter-body {
  text-align: left;
  display: inline-block;
  vertical-align: top;
  width: 960px;
  margin-right: 20px;
  margin-bottom: 20px;
  margin-left: 20px;
  margin-top: 20px;
}

.Top {
  text-align: left;
  max-width: 1000px;
}

.Top-image {
  margin-right: 20px;
  margin-bottom: 20px;
}

.Top-body {
  text-align: left;
  display: inline-block;
  vertical-align: top;
  width: 960px;
}

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


/* Add a black background color to the top navigation */
.topnav {
    background-color: #333;
    overflow: hidden;
}

/* Style the links inside the navigation bar */
.topnav a {
    float: left;
    color: #f2f2f2;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    font-size: 17px;
}

/* Change the color of links on hover */
.topnav a:hover {
    background-color: #ddd;
    color: black;
}

/* Add a color to the active/current link */
.topnav a.active {
    background-color: #4CAF50;
    color: white;
}

.Home {
  text-align: center;
}