CSS apply border to a cloud shape?

Question

I drew a cloud via CSS3 using different div tags I am trying to add a border to the whole shape but I am having trouble since every shape get its own border how can I apply a border to the whole cloud?

HTML:

<div id="cloud">
  <div id="bottom_c"></div>
  <div id="right_c"></div>
  <div id="left_c"></div>
</div>

CSS:

* {
  margin: 0;
  padding: 0;
  border: 0;
}

body{
  background-color: #4ca3ff;
}
#cloud {
  position: absolute;

}
#bottom_c {
  position: relative; top: 200px; left: 500px;
  width: 350px;
  height: 150px;
  background-color: #fff;
  border-radius: 100px;
  border: solid 5px black;
  z-index: 100;
}
#right_c{
  position: absolute; top: 140px; left: 640px;
  width: 150px;
  height: 150px;
  border-radius: 100%;
  background-color: #fff;
  border: solid 5px black;
}
#left_c{
  position: absolute; top: 170px; left: 550px;
  width: 100px;
  height: 100px;
  border-radius: 100%;
  background-color: #fff;
  border: solid 5px black;
}

Image:

Answer 1

You can do it without any additional elements. Just use the ::before and ::after pseudo-elements with the same size and round shape as the top cloud bubbles. z-index keeps everything in the right layer.

Demo:

Output:

CSS:

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;
}

HTML:

<div id="cloud">
  <div id="bottom_c"></div>
  <div id="right_c"></div>
  <div id="left_c"></div>
</div>