html, body {
  height: 100%;
  margin: 0;
  padding: 0;
  font-size: 16px;
}

body {  
  background-color: rgb(64, 64, 74);
  color: #ccc;
  font-family: Verdana;
  background-image: url('resources/psocavesred.jpg');
  background-attachment: fixed;
  background-size: cover;
  background-repeat: no-repeat;
  background-position: center;
  min-height: 100vh; /* ensures full viewport height */
  margin: 0;
  padding: 0;
}
a {
  color: #ccccff
}
a:hover {
  color: #eee 
}
a:visited {
 color: #666666 
}

section {
  background-color: rgba(64, 64, 74, 0.9);
  width: 800px;            /* or whatever max width you want */
  margin: 0 auto;          /* centers horizontally */
  padding: 20px;           /* optional */
}