What next for CSS Grid Layout?

In 2012 I wrote an article for 24 ways detailing a new CSS Specification that had caught my eye, at the time with an implementation only in Internet Explorer. What I didn’t realise at the time was that CSS Grid Layout was to become a theme on which I would base the next four years of research, experimentation, writing and speaking.

As I write this article in December 2016, we are looking forward to CSS Grid Layout being shipped in Chrome and Firefox. What will ship early next year in those browsers is expanded and improved from the early implementation I explored in 2012. Over the last four years the spec has been developed as part of the CSS Working Group process, and has had input from browser engineers, specification writers and web developers. Use cases have been discussed, and features added.

The CSS Grid Layout specification is now a Candidate Recommendation. This status means the spec is to all intents and purposes, finished. The discussions now happening are on fine implementation details, and not new feature ideas. It makes sense to draw a line under a specification in order that browser vendors can ship complete, interoperable implementations. That approach is good for all of us, it makes development far easier if we know that a browser supports all of the features of a specification, rather than working out which bits are supported. However it doesn’t mean that works stops here, and that new use cases and features can’t be proposed for future levels of Grid Layout. Therefore, in this article I’m going to take a look at some of the things I think grid layout could do in the future. I would love for these thoughts to prompt you to think about how Grid - or any CSS specification - could better suit the use cases you have.

Subgrid - the missing feature of Level 1

The implementation of CSS Grid Layout in Chrome, Firefox and Webkit is comparable and very feature complete. There is however one standout feature that has not been implemented in any browser as yet - subgrid. Once you set the value of the display property to grid, any direct children of that element become grid items. This is similar to the way that flexbox behaves, set display: flex and all direct children become flex items. The behaviour does not apply to children of those items. You can nest grids, just as you can nest flex containers, but the child grids have no relationship to the parent.

The subgrid behaviour would enable the grid defined on the parent to be used by the children. I feel this would be most useful when working with a multiple column flexible grid - for example a typical 12 column grid. I could define a grid on a wrapper, then position UI elements on that grid - from the major structural elements of my page down through the child elements to a form where I wanted the field to line up with items above.

The specification contained an initial description of subgrid, with a value of subgrid for grid-template-columns and grid-template-rows, you can read about this in the August 2015 Working Draft. This version of the specification would have meant you could declare a subgrid in one dimension only, and create a different set of tracks in the other.

In an attempt to get some implementation of subgrid, a revised specification was proposed earlier this year. This gives a single subgrid value of the display property. As we now cannot specify a subgrid on rows OR columns this limits us to have a subgrid that works in two dimensions. At this point neither version has been implemented by anyone, and subgrids are marked as “at risk” in the Level 1 Candidate Recommendation. With regard to ‘at-risk’ this is explained as follows:

“‘At-risk’ is a W3C Process term-of-art, and does not necessarily imply that the feature is in danger of being dropped or delayed. It means that the WG believes the feature may have difficulty being interoperably implemented in a timely manner, and marking it as such allows the WG to drop the feature if necessary when transitioning to the Proposed Rec stage, without having to publish a new Candidate Rec without the feature first.”

If we lose subgrid from Level 1, as it looks likely that we will, this does give us a chance to further discuss and iterate on that feature. My current thoughts are that I’m not completely happy about subgrids being tied to both dimensions and feel that a return to the earlier version, or something like it, would be preferable.

Further reading about subgrid

• My post from 2015 detailing why I feel subgrid is important
• My post based on the revised specification
• Eric Meyer’s thoughts on subgrid
• Write-up of a discussion from Igalia who work on the Blink and Webkit browser implementations

Styling cells, tracks and areas

Having defined a grid with CSS Grid Layout you can place child elements into that grid, however what you can’t do is style the grid tracks or cells. Grid doesn’t even go as far as multiple column layout, which has the column-rule properties.

In order to set a background colour on a grid cell at the moment you would have to add an empty HTML element or insert some generated content as in the below example. I’m using a 1 pixel grid gap to fake lines between grid cells, and empty div elements, and some generated content to colour those cells.

I think it would be a nice addition to Grid Layout to be able to directly add backgrounds and borders to cells, tracks and areas. There is an Issue raised in the CSS WG Drafts repository for Decorative Grid Cell pseudo-elements, if you want to add thoughts to that.

More control over auto placement

If you haven’t explicitly placed the direct children of your grid element they will be laid out according to the grid auto placement rules. You can see in this example how we have created a grid and the items are placing themselves into cells on that grid.

The auto-placement algorithm is very cool. We can position some items, leaving others to auto-place; we can set items to span more than one track; we can use the grid-auto-flow property with a value of dense to backfill gaps in our grid.

I think however this could be taken further. In this issue posted to my CSS Grid AMA on GitHub, the question is raised as to whether it would be possible to ask grid to place items on the next available line of a certain name. This would allow you to skip tracks in the grid when using auto-placement, an issue that has also been raised by Emil Björklund in this post to the www-style list prior to spec discussion moving to Github. I think there are probably similar issues, if you can think of one add a comment here.

Creating non-rectangular grid areas

A grid area is a collection of grid cells, defined by setting the start and end lines for columns and rows or by creating the area in the value of the grid-template-areas property as shown below. Those areas however must be rectangular - you can’t create an L-shaped or otherwise non-regular shape.

Perhaps in the future we could define an L-shape or other non-rectangular area into which content could flow, as in the below currently invalid code where a quote is embedded into an L-shaped content area.

.wrapper {
  display: grid;
  grid-template-areas:
      "sidebar header  header"
      "sidebar content quote"
      "sidebar content content";
}

Flowing content through grid cells or areas

Some uses cases I have seen perhaps are not best solved by grid layout at all, but would involve grid working alongside other CSS specifications. As I detail in this post, there are a class of problems that I believe could be solved with the CSS Regions specification, or a revised version of that spec.

Being able to create a grid layout, then flow content through the areas could be very useful. Jen Simmons presented to the CSS Working Group at the Lisbon meeting a suggestion as to how this might work.

In a post from earlier this year I looked at a collection of ideas from specifications that include Grid, Regions and Exclusions. These working notes from my own explorations might prompt ideas of your own.

Solving the keyboard/layout disconnect

One issue that grid, and flexbox to a lesser extent, raises is that it is very easy to end up with a layout that is disconnected from the underlying markup. This raises problems for people navigating using the keyboard as when tabbing around the document you find yourself jumping to unexpected places. The problem is explained by Léonie Watson with reference to flexbox in Flexbox and the keyboard navigation disconnect.

The grid layout specification currently warns against creating such a disconnect, however I think it will take careful work by web developers in order to prevent this. It’s also not always as straightforward as it seems. In some cases you want the logical order to follow the source, and others it would make more sense to follow the visual. People are thinking about this issue, as you can read in this mailing list discussion.

Bringing your ideas to the future of Grid Layout

When I’m not getting excited about new CSS features, my day job involves working on a software product - the CMS that is serving this very website, Perch. When we launched Perch there were many use cases that we had never thought of, despite having a good idea of what might be needed in a CMS and thinking through lots of use cases. The additional use cases brought to our attention by our customers and potential customers informed the development of the product from launch. The same will be true for Grid Layout.

As a “product” grid has been well thought through by many people. Yet however hard we try there will be use cases we just didn’t think of. You may well have one in mind right now. That’s ok, because as with any CSS specification, once Level One of grid is complete, work can begin on Level Two. The feature set of Level Two will be informed by the use cases that emerge as people get to grips with what we have now.

This is where you get to contribute to the future of layout on the web. When you hit up against the things you cannot do, don’t just mutter about how the CSS Working Group don’t listen to regular developers and code around the problem. Instead, take a few minutes and write up your use case. Post it to your blog, to Medium, create a CodePen and go to the CSS Working Group GitHub specs repository and post an issue there. Write some pseudo-code, draw a picture, just make sure that the use case is described in enough detail that someone can see what problem you want grid to solve. It may be that - as with any software development - your use case can’t be solved in exactly the way you suggest. However once we have a use case, collected with other use cases, methods of addressing that class of problems can be investigated.

I opened this article by explaining I’d written about grid layout four years ago, and how we’re only now at a point where we will have Grid Layout available in the majority of browsers. Specification development, and implementation into browsers takes time. This is actually a good thing, as it’s impossible to take back CSS once it is out there and being used by production websites. We want CSS in the wild to be well thought through and that takes time. So don’t feel that because you don’t see your use case added to a spec immediately it has been ignored. Do your future self a favour and write down your frustrations or thoughts, and we can all make sure that the web platform serves the use cases we’re dealing with now and in the future.