Flex-box: Align last row to grid

I have a simple flex-box layout with a container like:

.grid {
  display: flex;
  flex-flow: row wrap;
  justify-content: space-between;
}

Now I want the items in the last row to be aligned with the other. justify-content: space-between; should be used because the width and height of the grid can be adjusted.

Currently it looks like

Here, I want the item in the bottom right to be in the "middle column". What is the simplest way to accomplish that? Here is a small jsfiddle that shows this behaviour.

.exposegrid {
  display: flex;
  flex-flow: row wrap;
  justify-content: space-between;
}

.exposetab {
  width: 100px;
  height: 66px;
  background-color: rgba(255, 255, 255, 0.2);
  border: 1px solid rgba(0, 0, 0, 0.4);
  border-radius: 5px;
  box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.2);
  margin-bottom: 10px;
}

<div class="exposegrid">
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
  <div class="exposetab"></div>
</div>

Solution 1:

Add a ::after which autofills the space. No need to pollute your HTML. Here is a codepen showing it: http://codepen.io/DanAndreasson/pen/ZQXLXj

.grid {
  display: flex;
  flex-flow: row wrap;
  justify-content: space-between;
}

.grid::after {
  content: "";
  flex: auto;
}

Solution 2:

One technique would be inserting a number of extra elements (as many as the max number of elements you ever expect to have in a row) that are given zero height. Space is still divided, but superfluous rows collapse to nothing:

http://codepen.io/dalgard/pen/Dbnus

body {
  padding: 5%;
}

div {
  overflow: hidden;
  background-color: yellow;
}

ul {
  display: flex;
  flex-wrap: wrap;
  margin: 0 -4px -4px 0;
  list-style: none;
  padding: 0;
}

li {
  flex: 1 0 200px;
  height: 200px;
  border-right: 4px solid black;
  border-bottom: 4px solid black;
  background-color: deeppink;
}
li:empty {
  height: 0;
  border: none;
}

*,
:before,
:after {
  box-sizing: border-box;
}

<div>
  <ul>
    <li>a</li>
    <li>b</li>
    <li>c</li>
    <li>d</li>
    <li>e</li>
    <li>f</li>
    <li>g</li>
    <li>h</li>
    <li>i</li>
    <li>j</li>
    <li>k</li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
  </ul>
</div>

In the future, this may become achievable through using multiple ::after(n).

Solution 3:

As other posters have mentioned - there's no clean way to left-align the last row with flexbox (at least as per the current spec)

However, for what it's worth: With the CSS Grid Layout Module this is surprisingly easy to produce:

Basically the relevant code boils down to this:

ul {
  display: grid; /* 1 */
  grid-template-columns: repeat(auto-fill, 100px); /* 2 */
  grid-gap: 1rem; /* 3 */
  justify-content: space-between; /* 4 */
}

1) Make the container element a grid container

2) Set the grid with auto columns of width 100px. (Note the use of auto-fill (as apposed to auto-fit - which (for a 1-row layout) collapses empty tracks to 0 - causing the items to expand to take up the remaining space. This would result in a justified 'space-between' layout when grid has only one row which in our case is not what we want. (check out this demo to see the difference between them)).

3) Set gaps/gutters for the grid rows and columns - here, since want a 'space-between' layout - the gap will actually be a minimum gap because it will grow as necessary.

4) Similar to flexbox.

ul {
  display: grid;
  grid-template-columns: repeat(auto-fill, 100px);
  grid-gap: 1rem;
  justify-content: space-between;
  
  /* boring properties */
  list-style: none;
  background: wheat;
  padding: 2rem;
  width: 80vw;
  margin: 0 auto;
}

li {
  height: 50px;
  border: 1px solid green;
}

<ul>
  <li></li>
  <li></li>
  <li></li>
  <li></li>
  <li></li>
  <li></li>
  <li></li>
</ul>

Codepen Demo (Resize to see the effect)