How can I set a customized distance between child of flexbox - html

Question

<div class="container">
<div class="a"></div>
<div class="b"></div>
<div class="c"></div>
</div>
.container{
display: flex;
flex-direction: column;
justify-content: space-between;
height: 140;
}
.a{
margin-top: 10px;
height: 17px;
}
.b{
//??
height: 40px;
}
.c{
margin-bottom: 10px;
height: 18px;
}
I have three <div>s a, b and c in the container <div>. I want an element a to be positioned 10px to the top of the container, b to be positioned 50px to the top of the container and c to be positioned 10px to the bottom of the container.
How should I set b's style in order to achieve this? I want to avoid using absolute position if possible since when I tried to use it, somehow the width of b changed. I want to know if there is a way to set a customized distance between children of a flexbox.

Answer 1

Its easier that you adjust the distances here with margins - so you can remove justify-content: space-between.
Add margin-top: 23px to b and margin-top: auto to c. Check the below demo (you can inspect the red lines to verify that the distances are correct):
* {
box-sizing: border-box;
}
.container {
display: flex;
flex-direction: column;
/*justify-content: space-between;*/
height: 140px;
border: 1px solid;
position: relative;
}
.a {
margin-top: 10px;
height: 17px;
}
.b {
height: 40px;
margin-top: 23px; /* ADDED */
}
.c {
margin-bottom: 10px;
height: 18px;
margin-top: auto; /* ADDED */
}
/* STYLING */
.a,.b,.c {
border: 1px solid blue;
background: cadetblue;
}
.a:before,.b:before,.c:before {
content: '';
top: 0;
width: 2px;
position: absolute;
left: 100px;
background: red;
}
.a:before {
height: 10px;
}
.b:before {
height: 50px;
left: 200px;
}
.c:before {
left: 100px;
top: unset;
bottom: 0;
height: 10px;
}
<div class="container">
<div class="a"></div>
<div class="b"></div>
<div class="c"></div>
</div>