Edit in JSFiddle

body{
    background-color: #4ca3ff;
}

#cloud {
    height: 230px;
    margin: 40px;
    position: relative;
    width: 400px;
}

#cloud div {
    border: solid 5px black;
}

#bottom_c {
    background-color: #fff;
    border-radius: 100px;
    height: 150px;
    position: absolute; 
    top: 100px;
    width: 350px;
    z-index: 0;
}

#right_c{
    background-color: #fff;
    border-radius: 100%;
    height: 150px;
    left: 140px;
    position: absolute; 
    top: 40px; 
    width: 150px;
    z-index: -1;
}

#left_c{
    background-color: #fff;  
    border-radius: 100%;
    height: 100px;
    left: 50px;
    position: absolute; 
    top: 70px; 
    width: 100px;
    z-index: -1;
}

#cloud::before {
    background-color: white;
    border-radius: 50%;
    content: '';
    height: 100px;
    left: 55px;
    position: absolute; 
    top: 75px; 
    width: 100px;
    z-index: 1;
}

#cloud::after {
    position: absolute; top: 45px; left: 145px;
    background-color: white;
    border-radius: 50%;
    content: '';
    width: 150px;
    height: 150px;
    z-index: 1;
}