Remove space (gaps) between multiple lines of flex items when they wrap

I am trying to have a number of items underneath each other in a container with a set height. Items will then carry on next to each other if there's no space left.

This is the idea:

I am trying to achieve this using flexbox, a container with a set height, direction is set to column and flex-wrap is wrap:

The issue is that there are wide gaps between the columns.

I tried setting both justify-content and align-items to flex-start, but that is probably the default value.

Is there any way to solve this?

Here is the code:

* {
  box-sizing: border-box;
}
body {
  font-family: sans-serif;
}
.container {
  display: flex;
  flex-wrap: wrap;
  height: 300px;
  flex-direction: column;
  background-color: #ccc;
}
.items {
  width: 100px;
  height: 100px;
  margin: 10px;
  background-color: tomato;
  color: white;
  font-size: 60px;
  font-weight: bold;
  text-align: center;
  padding: 15px;
}

<div class="container">
  <div class="items">1</div>
  <div class="items">2</div>
  <div class="items">3</div>
  <div class="items">4</div>
  <div class="items">5</div>
</div>

codepen

An initial setting of a flex container is align-content: stretch.

This means that multiple lines of flex items will be distributed evenly along the cross axis.

To override this behavior, apply align-content: flex-start to the container.

---

When you're working in a single-line flex container (i.e., flex-wrap: nowrap), the properties to use to distribute space along the cross axis are align-items and align-self.

When you're working in a multi-line flex container (i.e., flex-wrap: wrap) – like in the question – the property to use to distribute flex lines (rows / columns) along the cross axis is align-content.

From the spec:

> 8.3. Cross-axis Alignment: the align-items and align-self properties

> align-items sets the default alignment for all of the flex container’s items, including anonymous flex items. align-self allows this default alignment to be overridden for individual flex items.

> 8.4. Packing Flex Lines: the align-content > property > > The align-content property aligns a flex container’s lines within the > flex container when there is extra space in the cross-axis, similar to > how justify-content aligns individual items within the main-axis. > Note, this property has no effect on a single-line flex container.

The align-content property takes six values:

• flex-start
• flex-end
• center
• space-between
• space-around
• stretch

Here's the definition for stretch:

> stretch > > Lines stretch to take up the remaining space. If the leftover free-space is negative, this value is identical to flex-start. Otherwise, the free-space is split equally between all of the lines, increasing their cross size. >

In other words, align-content: stretch on the cross axis is similar to flex: 1 on the main axis.