* {
  margin: 0;
  padding: 0;
  -webkit-box-sizing: border-box;
          box-sizing: border-box;
}

@media (min-width: 621px) {
  body {
    background: #333;
  }
}

@media (min-width: 621px) and (min-width: 500px) {
  body {
    background: #333;
  }
}

.spans {
  margin-top: 100px;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: center;
      -ms-flex-pack: center;
          justify-content: center;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
      -ms-flex-direction: column;
          flex-direction: column;
  -webkit-box-align: center;
      -ms-flex-align: center;
          align-items: center;
}

.spans span {
  display: block;
  width: 26px;
  height: 2px;
  background: #ccc;
  margin-bottom: 2px;
  -webkit-transition: all 0.3s ease-in-out;
  transition: all 0.3s ease-in-out;
  -webkit-transform-origin: 7.5px 1px;
          transform-origin: 7.5px 1px;
  -webkit-transform: rotate(360deg);
          transform: rotate(360deg);
}

.spans.open span:nth-child(1) {
  -webkit-transform: rotate(45deg);
          transform: rotate(45deg);
  background: green;
}

.spans.open span:nth-child(2) {
  opacity: 0;
}

.spans.open span:nth-child(3) {
  background: lightseagreen;
  -webkit-transform: rotate(-45deg);
          transform: rotate(-45deg);
}