I'm working on a layout using CSS flexbox and facing an issue where I want my flex items to behave in a specific way when the browser window is resized:

1. Desired Behaviour:

   • When the window width decreases, the flex items should wrap until their combined height reaches the container's height.

   • Once the container's height is reached, the items should stop wrapping and start shrinking instead.

2. Current Issue:
   Right now, the items continue wrapping and overflow the parent container's height.

Here is an example code showcasing my issue: Link to Flems.io

.container {
  font-family: arial, sans-serif;
  margin: 0;
  padding: 0;
  list-style-type: none;
  border: 2px dashed red;

  display: flex;
  align-items: flex-start;
  height: 120px;
  flex-wrap: wrap;
}

.flex {
  background: #6ab6d8;
  padding: 10px;
  border: 3px solid #2e86bb;
  color: white;
  font-size: 20px;
  text-align: center;

  width: 400px;
  flex: 0 1 auto;
  min-width: 0;
}

.flex2 {
  width: 300px;
}

<ul class="container">
  <li class="flex flex1">1: some flex item</li>
  <li class="flex flex2">2: some flex item</li>
  <li class="flex flex3">3: some flex item</li>
  <li class="flex flex4">4: some flex item</li>
  <li class="flex flex5">5: some flex item</li>
</ul>

I'm working on a layout using CSS flexbox and facing an issue where I want my flex items to behave in a specific way when the browser window is resized:

1. Desired Behaviour:

   • When the window width decreases, the flex items should wrap until their combined height reaches the container's height.

   • Once the container's height is reached, the items should stop wrapping and start shrinking instead.

2. Current Issue:
   Right now, the items continue wrapping and overflow the parent container's height.

Here is an example code showcasing my issue: Link to Flems.io

.container {
  font-family: arial, sans-serif;
  margin: 0;
  padding: 0;
  list-style-type: none;
  border: 2px dashed red;

  display: flex;
  align-items: flex-start;
  height: 120px;
  flex-wrap: wrap;
}

.flex {
  background: #6ab6d8;
  padding: 10px;
  border: 3px solid #2e86bb;
  color: white;
  font-size: 20px;
  text-align: center;

  width: 400px;
  flex: 0 1 auto;
  min-width: 0;
}

.flex2 {
  width: 300px;
}

<ul class="container">
  <li class="flex flex1">1: some flex item</li>
  <li class="flex flex2">2: some flex item</li>
  <li class="flex flex3">3: some flex item</li>
  <li class="flex flex4">4: some flex item</li>
  <li class="flex flex5">5: some flex item</li>
</ul>

I tried adding min-width: 0 to the flex items because I learned that flexbox sets min-width to auto by default, unlike other block-level elements where min-width is typically 0. However, this change didn’t solve the problem.

• css
• flexbox

Share Improve this question Follow edited Mar 23 at 2:47 zer00ne 44.4k66 gold badges4848 silver badges7979 bronze badges asked Mar 22 at 15:15 Lucas MartinianoLucas Martiniano 2311 silver badge22 bronze badges 4

• When you are using flex-wrap: wrap you are telling the container that it can wrap its elements for as long at it wants regardless of the container height. The container can not hold more than 2 of the blocks you have created so it will always overflow since it can't decide on if it wraps or shrinks. You can allow the child to shrink and grow by using flex-grow or flex-shrink on the child. – Kasper Commented Mar 22 at 16:19
• I see. I do allow the childs to shrink through flex: 0 1 auto, but I saw here that the flexbox algorithm wraps the flex items before shrinking them, so it doesn't do much. Is there any way to specify a maximum combined height for the wrapped flex items? If not, is there another way to tackle the issue? – Lucas Martiniano Commented Mar 22 at 16:37
• What's the min/max-width of <ul>? What's the minimum font-size you'd accept? Because at some point an area with 10px padding will no longer shrink. 120px of vertical space is meager. You should rethink your layout or overflow-y: scroll/auto to maintain a max-height: 120px. If you flex-direction: column then flex-wrap is no longer an issue. – zer00ne Commented Mar 23 at 3:42
• I agree that this layout is not the most convenient. I'm currently learning Flexbox, so I posted this question more as a challenge—to see if it could be solved using Flexbox—rather than as a real issue I encountered on a project. – Lucas Martiniano Commented Mar 23 at 11:20

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1 Answer 1

Sorted by: Reset to default 1

Maybe with container queries? We can detect the overflow event with the known widths of the children. A bit hacky, but is there a more natural way to do this without javascript?

* { box-sizing: border-box; min-width: 0; min-height: 0; }

.container {
  font-family: arial, sans-serif;
  margin: 0;
  padding: 0;
  list-style-type: none;
  border: 2px dashed red;

  display: flex;
  align-items: flex-start;
  height: 120px;
  flex-wrap: wrap;

  container-type: inline-size;
}

.flex {
  background: #6ab6d8;
  padding: 10px;
  border: 3px solid #2e86bb;
  color: white;
  font-size: 20px;
  text-align: center;

  width: 400px;
  flex: 0 1 auto;
}

.flex2 {
  width: 300px;
}

@container (max-width: 1100px) {
  .flex1 { flex-basis: calc(400 / 1100* 100%); }
  .flex2 { flex-basis: calc(300 / 1100* 100%); }
  .flex3 { flex-basis: calc(400 / 1100* 100%); }
  .flex4 { flex-basis: calc(400 / 1100* 100%); }
  .flex5 { flex-basis: calc(400 / 1100* 100%); }

  /* Debug color change */
  .flex {
    background-color: aqua;
  }
}

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <link rel="stylesheet" href="stylesheet.css">
</head>
<body>
  <ul class="container">
    <li class="flex flex1">1: some flex item</li>
    <li class="flex flex2">2: some flex item</li>
    <li class="flex flex3">3: some flex item</li>
    <li class="flex flex4">4: some flex item</li>
    <li class="flex flex5">5: some flex item</li>
  </ul>
</body>
</html>

P.S: To do this without container queries, it can also be done with grid. Its suggested and explained as a fallback in the documentation.