style.css

.box{
    float:center;
    margin-right:20px;
}
.clear{
    clear:both;
}

body{margin:0;padding:0;background:#000000;font-size:0.875rem;line-height:1.5em;font-family:Arial, Helvetica, sans-serif;color:#afafaf}

 /* The side navigation menu */
 .sidebar {
    margin: 0;
    padding: 0;
    width: 200px;
    background-color: rgb(48, 58, 48);
    position: fixed;
    height: 100%;
    overflow: auto;
  }
  
  /* Sidebar links */
  .sidebar a {
    display: block;
    color: black;
    padding: 16px;
    text-decoration: none;
  }
  
  /* Active/current link */
  .sidebar a.active {
    background-color: #042e04;
    color: rgb(44, 179, 39);
  }
  
  /* Links on mouse-over */
  .sidebar a:hover:not(.active) {
    background-color: #555;
    color: rgb(44, 179, 39);
  }
  
  /* Page content. The value of the margin-left property should match the value of the sidebar's width property */
  div.content {
    margin-left: 200px;
    padding: 1px 16px;
    height: 1000px;
  }
  
  /* On screens that are less than 700px wide, make the sidebar into a topbar */
  @media screen and (max-width: 600px) {
    .sidebar {
      width: 600;
      height: auto;
      position: relative;
    }
    .sidebar a {float: left;}
    div.content {margin-left: 0;}
  }
  
  /* On screens that are less than 400px, display the bar vertically, instead of horizontally */
  @media screen and (max-width: 400px) {
    .sidebar a {
      text-align: center;
      float: none;
    }
  } 

   {
    font-family: 'CustomFont', Exocet, sans-serif;
    font-weight:normal;
    font-style:normal;
    }

body {
    background: black;
}

iframe {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

 /* The alert message box */
.alert {
  padding: 20px;
  background-color: #f44336; /* Red */
  color: white;
  margin-bottom: 15px;
}

/* The close button */
.closebtn {
  margin-left: 15px;
  color: white;
  font-weight: bold;
  float: right;
  font-size: 22px;
  line-height: 20px;
  cursor: pointer;
  transition: 0.3s;
}

/* When moving the mouse over the close button */
.closebtn:hover {
  color: black;
} 
 /* Callout box - fixed position at the bottom of the page */
.callout {
  position: fixed;
  bottom: 35px;
  right: 20px;
  margin-left: 20px;
  max-width: 300px;
}

/* Callout header */
.callout-header {
  padding: 25px 15px;
  background: #555;
  font-size: 30px;
  color: white;
}

/* Callout container/body */
.callout-container {
  padding: 15px;
  background-color: #ccc;
  color: black
}

/* Close button */
.closebtn {
  position: absolute;
  top: 5px;
  right: 15px;
  color: white;
  font-size: 30px;
  cursor: pointer;
}

/* Change color on mouse-over */
.closebtn:hover {
  color: lightgrey;
}