Stretch columns in two columns layout with shared header using flexbox - html

Question

I'm using flexbox to create a two-columns layout with a header row.
* {
box-sizing: border-box;
position: relative;
}
.container {
border: 2px solid gray;
display: flex;
flex-wrap: wrap;
height: 300px;
}
.header {
flex-basis: 100%;
border: 2px solid magenta;
height: 50px;
line-height: 50px;
text-align: center;
}
.column1 {
flex-basis: 150px;
/* height: calc(100% - 50px); */
border: 2px solid green;
}
.column2 {
/* height: calc(100% - 70px); */
flex: 1;
border: 2px solid orange;
}
<div class='container'>
<div class='header'>it's a header</div>
<div class='column1'>column 1</div>
<div class='column2'>column 2</div>
</div>
Feel free to see the full example here.
As you can see in the example there is a gap between columns and header. My aim is to stretch columns vertically to fill whole empty space in the container.
I can achieve it by setting height property like calc(100% - <header-height>). Is it the correct way?
I just tried to use "flex" style and set align-items: stretch to the container and align-self: stretch to columns but without success. Did I probably miss something trying to implement it this way?

Answer 1

I think specifying flex-direction as column is appropriate in this case.
The second row is itself a flex element with the flex-direction: row. You can fill the rest of the remaining space using flex: 1, which is equivalent to flex-grow: 1.
* {
box-sizing: border-box;
}
.container {
border: 2px solid gray;
display: flex;
flex-direction: column;
flex-wrap: wrap;
height: 300px;
}
.header {
border: 2px solid magenta;
height: 50px;
line-height: 50px;
text-align: center;
}
.subcontainer {
display: flex;
flex-direction: row;
flex: 1;
}
.column1 {
flex-basis: 150px;
border: 2px solid green;
}
.column2 {
flex: 1;
border: 2px solid orange;
}
<div class='container'>
<div class='header'>it's a header</div>
<div class="subcontainer">
<div class='column1'>column 1</div>
<div class='column2'>column 2</div>
</div>
</div>

Answer 2

Do it like shown below
* {
box-sizing: border-box;
}
body,
html {
height: 100%;
}
.container {
border: 2px solid gray;
display: flex;
flex-direction: column;
height: 100%;
}
.header {
width: 100%;
border: 2px solid magenta;
height: 50px;
line-height: 50px;
text-align: center;
}
.body-container {
display: flex;
width: 100%;
flex: 1;
}
.column1 {
width: 50%;
border: 2px solid green;
}
.column2 {
width: 50%;
border: 2px solid orange;
}
<div class='container'>
<div class='header'>it's a header</div>
<div class="body-container">
<div class='column1'>column 1</div>
<div class='column2'>column 2</div>
</div>
</div>