style.css

body {
  font-family: helvetica, arial, sans-serif;
  font-size: 16px;
  line-height: 28px;
}

* {
  box-sizing: border-box;
  -moz-box-sizing: border-box;
  margin: 0;
  padding: 0;
  color: #303030;
}

h1 {
  height: 25px;
  width: 640px;
  position: absolute;
  top: 50%;
  left: 50%;
  margin-left: -322px;
  margin-top: -290px;
  font-size: 32px;
  letter-spacing: -1px;
}

section {
  display: none;
}

.bespoke-parent {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
}

.bespoke-slide {
  width: 640px;
  height: 480px;
  position: absolute;
  top: 50%;
  margin-top: -240px;
  left: 50%;
  margin-left: -320px;
}

section.bespoke-slide {
  -webkit-transition: all .3s ease;
  -moz-transition: all .3s ease;
  -ms-transition: all .3s ease;
  -o-transition: all .3s ease;
  transition: all .3s ease;
  display: block;
}

.bespoke-inactive {
  opacity: 0;
}

.bespoke-active {
  opacity: 1;
}