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 .

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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?

Answer 2

Basically I was trying to get my code to have a middle section on a 'row' to auto-adjust to the content on both sides (in my case, a dotted line separator). Like @Michael_B suggested, the key is using display:flex on the row container and at least making sure your middle container on the row has a flex-grow value of at least 1 higher than the outer containers (if outer containers don't have any flex-grow properties applied, middle container only needs 1 for flex-grow ).

Here's a pic of what I was trying to do and sample code for how I solved it.

 .row { background: lightgray; height: 30px; width: 100%; display: flex; align-items:flex-end; margin-top:5px; } .left { background:lightblue; } .separator{ flex-grow:1; border-bottom:dotted 2px black; } .right { background:coral; }

 <div class="row"> <div class="left">Left</div> <div class="separator"></div> <div class="right">Right With Text</div> </div> <div class="row"> <div class="left">Left With More Text</div> <div class="separator"></div> <div class="right">Right</div> </div> <div class="row"> <div class="left">Left With Text</div> <div class="separator"></div> <div class="right">Right With More Text</div> </div>