So far everything we’ve touched with flexbox has used the rule
flex: 1 on all flex items, which makes the items grow or shrink equally to fill all of the available space. Very often, however, this is not the desired effect. Flex is also very useful for arranging items that have a specific size.
Let’s look at another example.
You should be able to predict what happens if you put
flex: 1 on the
.item by now. Give it a shot before we move on!
flex: 1 to
.item makes each of the items grow to fill the available space, but what if we wanted them to stay the same width, but distribute themselves differently inside the container? We can do this!
flex: 1 from
.item and add
justify-content: space-between to
.container. Doing so should give you something like this:
justify-content aligns items across the main axis. There are a few values that you can use here. You’ll learn the rest of them in the reading assignments, but for now try changing it to
center, which should center the boxes along the main axis.
To change the placement of items along the cross axis use
align-items. Try getting the boxes to the center of the container by adding
align-items: center to
.container. The desired result looks like this:
align-items are based on the main and cross axis of your container, their behavior changes when you change the flex-direction of a flex-container. For example, when you change
justify-content aligns vertically and
align-items aligns horizontally. The most common behavior, however, is the default, i.e.
justify-content aligns items horizontally (because the main axis defaults to horizontal), and
align-items aligns them vertically. One of the biggest sticking points that beginners have with flexbox is confusion when this behavior changes.
One more very useful feature of flex is the
gap property. Setting
gap on a flex container simply adds a specified space between flex items, very similar to adding a margin to the items themselves.
gap is a very new property so it doesn’t show up in very many resources yet, but it works reliably in all modern browsers, so it is safe to use and is very handy! Adding
gap: 8px to the centered example above produces the result below.
There’s more for you to learn in the reading below, but at this point surely you can see how immensely useful flexbox is. Using just the properties we’ve already covered you could already put together some impressive layouts!
Take your time going through the reading. There will be some review of the items we’ve already covered here, but it goes into more depth and touches on a few things that haven’t been mentioned yet. Don’t stress too much about trying to memorize every little detail yet; just code along with the examples and do your best to internalize everything that is possible with flexbox. You’ll have to reach for these resources again once you get to the practice exercises, but that’s perfectly acceptable. The more you use this stuff the better it will stick in your mind… and you will be using it constantly. Have fun!
When doing the following exercises, please use all the documentation and resources you need to accomplish them. You are not intended to have any of this stuff memorized at this point. Check the docs, use google, do what you need to do (besides checking the solutions) to get them done.
Go back to our CSS exercises repository (you’ve done these previously, but don’t forget that the instructions are in the README). Do the exercises in the ‘flex’ directory in the following order:
It may take you a while to get through all of them, and the difficulty ramps up as you progress. Stick with it! If you can get through all of them, then you will be in really good shape moving forward.
This section contains helpful links to other content. It isn’t required, so consider it supplemental.
This section contains questions for you to check your understanding of this lesson. If you’re having trouble answering the questions below on your own, review the material above to find the answer.