seahub/frontend/src/css/svg-file-view.css

.svg-file-view {
  position: relative;
  text-align: center;
}

.svg-file-view:before {
  content: ' ';
  display: inline-block;
  vertical-align: middle;
  height: 100%;
  font-size: 0;
  line-height: 0;
}

#svg-view {
  max-width: 100%;
  max-height: 100%;
}