.gallery {
  column-rule: 0px solid #eee;
  column-gap: 17px;
  width: 100%;
  margin: 0 auto;
}
.gallery.gallery-columns {
  -webkit-column-count: 2;
  /* Chrome, Safari, Opera */
  -moz-column-count: 2;
  /* Firefox */
  column-count: 2;
}

.gallery .gallery-item {
  display: inline-block;
  vertical-align: top;
  margin-bottom: 17px;
  max-width: 100%;
  width: 100%;
}
.gallery .gallery-item img{
  max-width: 100%;
  height:auto;
  display:block;
  margin: 0 auto;
	width: 100%;
}
pre{
	background-color: #e8e8e8;
	padding:5px;
}

button {
    display: inline-block;
    height: 200px;
		width: 400px;
    padding: 0;
    margin: 0;
}

@media only screen and (max-width: 720px) {
  .gallery.gallery-columns {
    -webkit-column-count: 1;
    /* Chrome, Safari, Opera */
    -moz-column-count: 1;
    /* Firefox */
    column-count: 1;
  }
}