Vertical reordering in CSS

There are plenty of techniques for reordering content horizontally in CSS (by reordering content I mean visually laying out content in an order different than the one in the source code). Usually those rely on a combination of clever floats and negative margins. YAML has a few examples.

A different objective would be to reorder content vertically, though. This could be particularly interesting for responsive design, where you would want to present content in a different order at different breakpoints, or maybe for a print stylesheet. After a bit of research I came across an interesting technique that relies on the fact that most browsers tend to render <caption> <thead> table elements above the table contents, even if the <caption> <thead> itself is at the bottom of the table in the markup. Of course, you don't need real <table> and <caption> <thead> elements; instead making use of CSS's table-caption table-row-header value for the display property.

Update: I got it a bit wrong; the technique used by Marat on his blog used display: table-header-group, not table-caption. Marat did some research into the problems of using table-caption; I was unfortunate to find a few other when using table-header-group.

I was not quite satisfied with the solution above — although it saved my backside a couple of times. It didn't work in IE, and it revealed a few browser bugs on Chrome (I guess display: table-row-header is not the most well tested CSS feature). So, a bit more experimenting and I struck at this idea:

So, we simply rotate a container 180° (upside down) and then rotate each child in-place another 180°. Magic! Seems to work wonders in Firefox, Safari, Chrome… and IE9.

Of course, IE versions less than 9 don't understand the CSS transform property, but there's still something we can do if we need to support those browsers (which, remember, we might not have to do if we are using this technique to target responsive design). Yes, we have to rely on the icky filter property… specifically, the "matrix" filter: it allows for rotation, scaling and skewing. We just need rotation. Unfortunately, it's been a long time since I did anything to do with matrices. Fortunately, someone else has made it easy — as easy as copy and paste. We also need to be a bit careful with preventing overlap of the filter property with transform in IE9 (since it supports both), so we use IE's conditional comments to keep the CSS clean. Here we go:

The filter solution should play well with IE6-8, but filter is notoriously buggy. In my quick testing I found at least two issues that might be deal breakers for you:

• <input> fields within the rotated sections don't display the input caret correctly (the field works as normal but the blinking cursor renders in the original position — go figure)
• rotated sections must have a background or they render as black squares, or with badly aliased text

A few more words of warning about this technique in general:

• your markup must make semantic sense regardless of how it is presented (this might actually help towards that, if used correctly)
• remember keyboard navigation: you might need to re-assign tabindex attributes for it to make sense to tab between links/fields
• this is not a tried-and-tested method; expect "issues"!