logo.css

body {
  margin: 150px;
  text-align: center;
}

.mango,
.mango span {
  width: 250px;
  height: 250px;
  line-height: 250px;
  border-radius: 50% / 12%;
  overflow: hidden;
  display: inline-block;
}

.mango {
  text-align: center;
  -webkit-transform: rotate(90deg);
  -moz-transform: rotate(90deg);
  transform: rotate(90deg);
}

.mango span {
  font-family: "Helvetica Neue", Helvetica, Arial;
  font-size: 9em;
  color: #fff;
  background-color: #19B530;
  -webkit-transform: rotate(-90deg);
  -moz-transform: rotate(-90deg);
  transform :rotate(-90deg);
}

.mango span:before,
.mango span:after {
  display: inline-block;
  font-size: 1.2em;
  line-height: 1em;
  left: .69em;
  position: absolute;
  -webkit-transform: rotate(90deg);
  -moz-transform: rotate(90deg);
  transform: rotate(90deg);
  font-weight: 500;
}

.mango span:before {
  content: '[';
  top: -8px;
}

.mango span:after {
  content: ']';
  bottom: -8px;
}