.balls {
    border-radius: 50%;
    top: 249px;
    position: fixed;
    width: 50px;
    height: 50px;
    top: 60%;
    animation-name: jump;
    animation-duration: 2s;
    animation-iteration-count: infinite;
  }
  #red {
    background: red;
    left: 25%;
    animation-timing-function: linear;
  }
  #blue {
    background: blue;
    left: 50%;
    animation-timing-function: ease-out;
  }
  #green {
    background: green;
    left: 75%;
    // animation-timing-function: cubic-bezier(0.69, 0.1, 1, 0.1); //bouncing balls rotete...
    animation-timing-function: cubic-bezier(0.311, 0.441, 0.444, 1.649); //smooth
  }
  
  @keyframes jump {
    50% {
      top: 10%;
    }
  }