html, body {
  height: 100%;
}
body {
  width: 35em;
  margin: 0 auto;
  font-family: Tahoma, Verdana, Arial, sans-serif;
  height: 100%;
  width: 100%;
  background-image: url("images/esquelets.jpg");
  background-size: 20%;
}

div.main-container {
  height: 100%;
  width: 100%;
  overflow: hidden;
}

/** Powered by Debian */
.ribbon-banner {
  display: block;
  position: fixed;
  bottom: 50px;
  right: -120px;
  width: 400px;
  height: 50px;
  line-height: 50px;
  text-align: center;
  opacity: 0.9;
  -webkit-transform: rotate(-45deg);
  -moz-transform:    rotate(-45deg);
  -ms-transform:     rotate(-45deg);
  transform:         rotate(-45deg);
  font-size: 20px;
  font-weight: 700;
  color: white;
  background-color: #D70A53;
  border: 1px solid white;
  z-index: 500;
}
.ribbon-banner a {
  text-decoration: none;
  color: white;
}

/** menu */
* {
  margin: 0;
  padding: 0;
}
nav {
  margin: 84px;
  margin-left: auto;
  margin-right: auto;
  text-align: center;
  display: table;
  /* display: none; */
  background-color: black;
  padding: 20px;
  opacity: 0.7;
}
ul {
  list-style-type: none;
}
li {
  height: 25px;
  float: left;
  margin-right: 0px;
  border-right: 1px solid #aaa;
  padding: 0 20px;
}
li:last-child {
  border-right: none;
}
li a {
  text-decoration: none;
  color: #ccc;
  font: 25px/1 Helvetica, Verdana, sans-serif;
  text-transform: uppercase;
}
li a:hover {
  color: #fff;
}
li.active a {
  font-weight: bold;
  color: #333;
}