Subtle CSS Error

An exercise in debugging Cascading Style Sheets

We launched a new version of the work website this week. We’re still tweaking things, but overall, I like the look of it, especially the subpages. The report pages haven’t looked this good in ages. I think I’ve kind of fallen in love with Open Sans, the font used in the new design, and I like that it comes in both bold and semi bold versions.

Just before we launched, though, we ran into one of those wonderful head scratchers that seem to be the hallmark of web development. We were clicking through the various views, and Garry clicked into the screen to edit an address. In IE, (of course) there was nothing there except the Save button at the top of the page. Since the section is loaded via Ajax, my first thought was that it was some sort of problem with loader script, especially since I was seeing Javascript errors in the error console. I found that error, fixed it, but it still didn’t fix the page.

Brute Force Debugging

Obviously, since we were dealing with a new theme and a new style sheet, those could be the culprit. So was it the new HTML or the new CSS? Turning off CSS showed the form, but was that issue?  Nothing obvious leapt out at me, and I had no idea where to even start looking. Finally, I bit the bullet, saved a backup copy of the stylesheet, then deleted the last third of it. No luck. I reinstated the section I deleted, then deleted another section. Still no luck. Finally, removing lines 400 to 700 revealed the form. From there, it was a simple matter of removing smaller and smaller parts of the stylesheet, until we zeroed in on the offending line.

Here it is:

main .controlbar .minibutton, main .controlbar .minibuttonactive {width:auto; display:inline;  text-align:center;  margin: .07em 0 .34e7em}

Do you see it?

The problem arose out of the fact that, for accessibility’s sake, we’re using ems instead of pixels (px) as units of measurement, because they make it much easier for a user to resize their screen. Pixels tend to be simple integers; ems are often decimals, and in a longish decimal, a typo can hide. In this case, the margin should be

margin: .07em 0 .347em

Once I narrowed into the right line, it was immediately obvious. Nearly an hour to find, 10 seconds to fix.

New Year, New Look

Just in time for the new year, I’ve revamped the appearance of the site. This is something I’ve been wanting to do since I first set up the site, but I had the notion that I needed to create a whole new theme, and was very slowly working my way through a WordPress book.

As it turns out, that wasn’t necessary. WordPress supports child themes–it isn’t necessary to create a whole new theme, you can simply override the parts of an existing theme that you want to. In this case, I’m basing my theme on the default TwentyEleven theme I was already using.

I’d fallen in love with the theme’s header image feature, and had already created some really nice banners from some of my pictures. But I wanted more color, I wanted to play with web fonts, and I wanted an appearance that was mine.


The fonts I’m now using are Museo Slab for the titles and Museo Sans for the main body text. Right now, I’m using TypeKit to provide them. One thing I’m less than crazy about is that you need to add a script to bring them in, and they’re hosted by TypeKit. I need to look into self-hosting them.


The main blue background is a PNG gradient applied to the HTML (root) element, with the “words” as a repeating PNG image applied to the BODY element. I’m of two minds about this background, from an accessibility standpoint. On the one hand, they’re meant to denote some of my interests, which would indicate that that some programmatically determinable method should be available. On the other hand, they’re meant to be decorative and kind of subliminal, and not to be really read. They’re not in a meaningful order, and in fact, you can’t see them all. They’re almost just texture. In the end, this is the line of thought I’ve followed.

The other gradients are created via CSS, using code based on ColorZilla’s Ultimate CSS Gradient Generator.

HTML Changes

Most of the generated HTML is still straight TwentyEleven. During development, I had to replace the stylesheet link with a hard coded link to my development site– WordPress is absolutely bloody-minded about using absolute links, which makes things needlessly complicated when you’re developing on a development domain. The one HTML change I’ve made so far is to add a little markup to facilitate the “posted on” calendar, which I implemented via a filter in my child theme.

One other change I want to implement in the future (hopefully, near future) is to provide alternative text for the header image. Surprisingly, the stock theme only provides an empty alt attribute with no easy way to add alternative text, and from what little I saw on the support forums last night, this was a design decision–I gather the feeling is that they regard the header image as being strictly decorative, and want to head off keyword stuffing. I can see that, but I can also see a site creating header images that include text, which would need alternative text. In my case, I’d like to add alternative text indicating what the header is a picture of, and it would even be nice to add a little visible caption with that information.

Browser Support

The site looks great in Safari, Opera, Chrome, and current Mozilla browsers like Firefox or Camino. I’ve looked at it in IE 7 and 8, and it looks good in those browsers too, though it’s missing some of the niceties like text embossing and rounded corners.  I haven’t seen it yet in IE 9. I am aware of an issue in older Mozilla browsers — the typography is missing, as is the gray background at the top, due to a bug in the way those browsers dealt with unknown elements. (The site uses some of the new HTML 5 features). The site is still readable, though, and the work-around– serving the site to Mozilla as text/xml– is risky, since one misplaced entity or malformed comment or post would blow the page out of the water. In the end, I’ve decided to accept that older Gecko based browsers won’t see as nice a presentation of the site. Fortunately, usage of these browsers is well under 1%.

Update 1/4/12:

I’ve now seen it in IE 9, and of course, IE Is Being IE. Earlier versions of Internet Explorer don’t support rounded corners, but IE 9 does. Unfortunately, since I was using an IE filter style to provide the top gray gradient, there were square corners poking out of the header. Apparently, it can’t clip the rounded corners when using older filter styles. I’ve replaced that gradient with an image; which took care of the problem.

Future Plans

As I stated above, I’d like to add alternative text/captioning to the header images, and I may add a little control to the home page enabling the user so rotate through the images without reloading the page. I also need to look into a widget to display tweets (I’m @ShutterAperture on Twitter). I will be adding an About page, and uploading and providing links to some of my older static pages that I was hosting either on Comcast when I was using them, or MobileMe. And in two weeks, I’ll be heading to Bonaire for a week of diving, and am looking forward to blogging about that.

Happy New Year, everyone.