Inline flex container (display: inline-flex) is expanding the full width of parent container

Question

I have a DIV with display: block (.out).

In this DIV there is a flexbox with display: inline-flex (.row) that has

Answer 1

Use width: 350px instead of flex-basis: 350px.

In your code, .row is first sized summing the width of its contents. Since .infos has no width, its initial size is given by its very long content. So .row fills all the available space in its containing block. It's after the size of .row has been determined that the flex items do flex and .infos becomes 350px. But then it's too late, .row is already too wide.

If you use width: 350px, .row will be sized using that value, without taking extra space.

.out {
  border: 1px solid red;
  display: block;
  position: fixed;
  top: 0;
  left: 0;
}
.row {
  display: inline-flex;
  flex-direction: row;
  padding: 10px;
  border: 1px solid yellow;
}
.infos {
  border: 1px solid green;
  width: 350px;
}
.dynamic {
  border: 1px solid blue;
  flex: 1 1;
}

  

    

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