// slideshow image placement

.slideshow img{
  position: absolute;
  top: 10em;
  left: 0;
  width: 100%;
  height:250px;
  overflow: hidden;
}

// other styles

header {
  font-family: Arial, Helvetica, sans-serif;
  text-align:center;
  height: 10em;
  padding: 2em;
}