body {
  text-align: center;
}
ul {
  width: 225px;
  margin: 0;
  padding: 0;
  list-style:none;
}
li {
  float: left;
  width: 100px;
  height: 100px;
  margin: 5px;
  border: 1px solid #cccccc;
  border-radius: 10px;
  line-height: 100px;
  text-align: center;
}