* {
    margin: 0;
    padding: 0;
}

body {
    margin-left: auto;
    margin-right: auto;
    max-width: 960px;
}
nav ul {
    margin-left: 130px;
    margin-top: 20px;
    margin-bottom: 10px;
}

nav li {
    list-style-type: none;
    display: inline;
}

nav a:link {
    list-style-type: none;
    display: inline;
    font-family: sans-serif;
    font-size: 20px;
    color: rgb(0,0,0);
    margin-right: 20px;
    text-transform: uppercase;
    text-decoration: none;
}

nav a:hover {
    color: rgb(155,155,155);
}

ul img {
    width: 100%;
    border-radius: 3%;
}

ul.img-list {
  list-style-type: none;
  margin: 0;
  padding: 0;
  text-align: center;
}

ul.img-list li {
  display: inline-block;
  height: 112px;
  margin: 15px;
  position: relative;
  width: 150px;
}

span.text-content span {
  display: table-cell;
  text-align: center;
  vertical-align: middle;
}

ul.img-list li:hover span.text-content {
  opacity: 1;
}

span.text-content {
  background: rgba(0,0,0,0.5);
  color: white;
  cursor: pointer;
  display: table;
  height: 112px;
  left: 0;
  position: absolute;
  top: 0;
  width: 150px;
  opacity: 0;
  -webkit-transition: opacity 500ms;
  -moz-transition: opacity 500ms;
  -o-transition: opacity 500ms;
  transition: opacity 500ms;
}