Equal height sections within flexbox columns?

Question

I\'m using flexbox columns for a pretty basic layout. There is a header, image and a list below. List must have a border and can have varying contents. Is it possible to hav

Answer 1

Since both columns are inside the same flex container, yes, the list boxes can be the same height (based on the tallest content) using only CSS.

.columns {
  display: flex;
}

.col {  
  display: flex;          /* new */
  flex-direction: column; /* new */
  margin-left: 20px;
}

.list {
  flex: 1;                /* new */
  padding: 24px;
  border: 1px solid blue;
}

ul {
  margin: 0;
}

<div class="columns">
  <div class="col">
    <h3>Header</h3>
    <div class="list">
      <ul>
        <li>List item</li>
        <li>List item</li>
      </ul>
    </div>
  </div>
  <div class="col">
    <h3>Header</h3>
    <div class="list">
      <ul>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
      </ul>
    </div>
  </div>
</div>

Here are a few more examples:

jsFiddle demo

.columns {
  display: flex;
}

.col {
  display: flex;           /* new */
  flex-direction: column;  /* new */
  margin-left: 20px;
}

.list {
  flex: 1;                 /* new */
  padding: 24px;
  border: 1px solid blue;
}

ul {
  margin: 0;
}

<div class="columns">
  <div class="col">
    <h3>Header</h3>
    <div class="list">
      <ul>
        <li>List item</li>
        <li>List item</li>
      </ul>
    </div>
  </div>
  <div class="col">
    <h3>Header</h3>
    <div class="list">
      <ul>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
      </ul>
    </div>
  </div>
</div>

<br>

<div class="columns">
  <div class="col">
    <h3>Header</h3>
    <div class="list">
      <ul>
        <li>List item</li>
        <li>List item</li>
      </ul>
    </div>
  </div>
  <div class="col">
    <h3>Header</h3>
    <div class="list">
      <ul>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
      </ul>
    </div>
  </div>
</div>

<br>

<div class="columns">
  <div class="col">
    <h3>Header</h3>
    <div class="list">
      <ul>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>
        <li>List item</li>        
      </ul>
    </div>
  </div>
  <div class="col">
    <h3>Header</h3>
    <div class="list">
      <ul>
        <li>List item</li>
        <li>List item</li>
      </ul>
    </div>
  </div>
</div>

Answer 2

You should set .col as flex too

.col{ display:flex; }

and your class columns is better named row