chromium/third_party/blink/web_tests/virtual/threaded/synthetic_gestures/synthetic-pinch-zoom-gesture.css

body, html {
  width: 100%;
  height: 100%;
  margin: 0;
}

div {
  background-color: green;
  width: 100px;
  height: 100px;
  position: absolute;
  left: 50%;
  top: 50%;
  margin-left: -50px;
  margin-top: -50px;
}