#center {
    text-align: center;
}

html {
    background-color: black;
}

hr {
    color: green;
}

.scroll-box{
    height:200px;
    width:800px;
    border:1px solid #080;
    overflow:auto;
    margin: 20px;
    padding: 20px;
}

.body {
    margin: 48px;
    clear: right;
    color: green;
    font-size: 24px;
    font-family: monospace;
    background-color: black;
}

.topnav {
  background-color: #111111;
  overflow: hidden;
}
.topnav a {
  float: left;
  color: #00e200;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 17px;
}
.topnav a:hover {
  background-color: #008800;
  color: black;
}
.topnav a.active {
  background-color: #00a800;
  color: black;
}

.collapsible {
  background-color: #000;
  color: green;
  cursor: pointer;
  padding: 18px;
  width: 100%;
  border: none;
  text-align: left;
  outline: none;
  font-size: 15px;
  font-family: monospace;
  border:4px solid #080;
}
.active, .collapsible:hover {
  background-color: #222;
}
.content {
  padding: 0 18px;
  display: none;
  overflow: hidden;
  background-color: #000;
  color: green;
  border:4px solid #080;
}