html, body
{
}

div#stripes {
  height:100%;
  width:100%;
  background-color: rgb(255, 251, 0);
  background-image: linear-gradient(45deg, #000 25%, transparent 25%, transparent 50%, #000 50%, #000 75%, transparent 75%, rgb(255, 251, 0));
  background-size: 50px 50px;
}

.container
{
    text-align: center;
}

.container:before
{
    content: '';
    height: 100%;
    display: inline-block;
    vertical-align: middle;
}

.content
{
    display: inline-block;
    vertical-align: middle;
}