Used all css3 techniques possible

index.slim

.container
  .frog
    .left-eye
    .right-eye
    .mouth

style.scss

@import "compass";
.container{
  margin: 120px auto;
    width: 20%;
  .frog{
    background: none repeat scroll 0 0 #92AE57;
    border-radius: 50% 50% 50% 50%;
    height: 0;
    padding-top: 60%;
    position: relative;
    width: 100%;
    &:after{
    background: none repeat scroll 0 0 #6F8346;
    border-radius: 50% 50% 50% 50%;
    content: "";
    height: 10%;
    left: 42.00%;
    position: absolute;
    top: 56.00%;
    width: 6%;
    z-index: 1;
    }
    &:before{
    background: none repeat scroll 0 0 #6F8346;
    border-radius: 50% 50% 50% 50%;
    content: "";
    height: 10%;
    left: 50.00%;
    position: absolute;
    top: 56.00%;
    width: 6%;
    z-index: 1;
    }
    .left-eye,.right-eye{
    background: none repeat scroll 0 0 #FFE13B;
    border: 10px solid #92AE57;
    border-radius: 50% 50% 50% 50%;
    height: 68.00%;
    left: -4.00%;
    position: absolute;
    top: -18.00%;
    width: 45.00%;
   &:before{
    background: none repeat scroll 0 0 black;
    border-radius: 50% 50% 50% 50%;
    content: "";
    height: 38%;
    left: 50%;
    margin-left: -17.0%;
    margin-top: -19%;
    position: absolute;
    top: 50%;
    width: 35%;
      }
    }
    .right-eye{
    left: auto;
    right:-4.5%;
    }
    .mouth{
    height: 50%;
    left: 1.7%;
    overflow: hidden;
    position: absolute;
    top: 60%;
    width: 100%;
      &:after{
      background: none repeat scroll 0 0 #71803F;
        border-radius: 50% 50% 50% 50%;
      content: "";
      height: 100%;
      left: 0;
      position: absolute;
      top: -50%;
      width: 97%;
      background: none repeat scroll 0 0 #92AE57;
      height: 80%;
      left: 0;
      top: -40%;
      }
      &:before{
        background: none repeat scroll 0 0 #71803F;
        border-radius: 50% 50% 50% 50%;
        content: "";
        height: 100%;
        left: 0;
        position: absolute;
        top: -50%;
        width: 97%;
      }
    }
  }
}