html - Fill the remaining height or width in a flex container

Question

I have 2 divs side-by-side in a flexbox. The right hand one should always be the same width, and I want the left hand one to just grab the remaining space. But it won't unless I specifically set its width.

So at the moment, it's set to 96% which looks OK until you really squash the screen - then the right hand div gets a bit starved of the space it needs.

I guess I could leave it as it is but it feels wrong - like there has to be a way to say:

the right one is always the same; you on the left - you get everything that's left

.ar-course-nav {
  cursor: pointer;
  padding: 8px 12px 8px 12px;
  border-radius: 8px;
}
.ar-course-nav:hover {
  background-color: rgba(0, 0, 0, 0.1);
}

<br/>
<br/>
<div class="ar-course-nav" style="display:flex; justify-content:space-between;">
  <div style="width:96%;">
    <div style="overflow:hidden; white-space:nowrap; text-overflow:ellipsis;">
      <strong title="Course Name Which is Really Quite Long And Does Go On a Bit But Then When You Think it's Stopped it Keeps on Going for even longer!">
                Course Name Which is Really Quite Long And Does Go On a Bit But Then When You Think it's Stopped it Keeps on Going for even longer!
            </strong>
    </div>
    <div style="width:100%; display:flex; justify-content:space-between;">
      <div style="color:#555555; margin-right:8px; overflow:hidden; white-space:nowrap; text-overflow:ellipsis;" title="A really really really really really really really really really really really long department name">
        A really really really really really really really really really really really long department name
      </div>
      <div style="color:#555555; text-align:right; white-space:nowrap;">
        Created: 21 September 2016
      </div>
    </div>
  </div>
  <div style="margin-left:8px;">
    <strong>&gt;</strong>
  </div>
</div>

Answer 1

Use the flex-grow property to make a flex item consume free space on the main axis.

This property will expand the item as much as possible, adjusting the length to dynamic environments, such as screen re-sizing or the addition / removal of other items.

A common example is flex-grow: 1 or, using the shorthand property, flex: 1.

Hence, instead of width: 96% on your div, use flex: 1.

---

You wrote:

So at the moment, it's set to 96% which looks OK until you really squash the screen - then the right hand div gets a bit starved of the space it needs.

The squashing of the fixed-width div is related to another flex property: flex-shrink

By default, flex items are set to flex-shrink: 1 which enables them to shrink in order to prevent overflow of the container.

To disable this feature use flex-shrink: 0.

For more details see The flex-shrink factor section in the answer here:

• What are the differences between flex-basis and width?

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Learn more about flex alignment along the main axis here:

• In CSS Flexbox, why are there no "justify-items" and "justify-self" properties?

Learn more about flex alignment along the cross axis here:

• How does flex-wrap work with align-self, align-items and align-content?