body {
  background-image: url(../img/ba.png);
}

.coo {
    text-align: center;  
    margin-top: 100px;
  }

  .coo img {
    width: 50%;
  }

  @media screen and (max-width: 520px) {

    .coo {
      text-align: center;  
      margin-top: 50px;
    }
  
    .coo img {
      width: 80%;
    }
  

}