$banner-width: 300px;
$banner-height: 250px;

*,
*:before,
*:after {
  box-sizing: inherit;
  margin: 0;
  padding: 0;
}

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

.banner {
  background: #fff;
  border: 1px solid #ccc;
  box-sizing: border-box;
  cursor: pointer;
  height: $banner-height;
  left: 50%;
  overflow: hidden;
  position: relative;
  position: absolute;
  transform: translate(-50%, -50%);
  top: 50%;
  width: $banner-width;
}