rowid,title,contents,year,author,author_slug,published,url,topic 330,An Explanation of Ems,"Ems are so-called because they are thought to approximate the size of an uppercase letter M (and so are pronounced emm), although 1em is actually significantly larger than this. The typographer Robert Bringhurst describes the em thus: The em is a sliding measure. One em is a distance equal to the type size. In 6 point type, an em is 6 points; in 12 point type an em is 12 points and in 60 point type an em is 60 points. Thus a one em space is proportionately the same in any size. To illustrate this principle in terms of CSS, consider these styles: #box1 { font-size: 12px; width: 1em; height: 1em; border:1px solid black; } #box2 { font-size: 60px; width: 1em; height: 1em; border: 1px solid black; } These styles will render like: M and M Note that both boxes have a height and width of 1em but because they have different font sizes, one box is bigger than the other. Box 1 has a font-size of 12px so its width and height is also 12px; similarly the text of box 2 is set to 60px and so its width and height are also 60px.",2005,Richard Rutter,richardrutter,2005-12-02T00:00:00+00:00,https://24ways.org/2005/an-explanation-of-ems/,design 318,Auto-Selecting Navigation,"In the article Centered Tabs with CSS Ethan laid out a tabbed navigation system which can be centred on the page. A frequent requirement for any tab-based navigation is to be able to visually represent the currently selected tab in some way. If you’re using a server-side language such as PHP, it’s quite easy to write something like class=""selected"" into your markup, but it can be even simpler than that. Let’s take the navigation div from Ethan’s article as an example.
As you can see we have a standard unordered list which is then styled with CSS to look like tabs. By giving each tab a class which describes it’s logical section of the site, if we were to then apply a class to the body tag of each page showing the same, we could write a clever CSS selector to highlight the correct tab on any given page. Sound complicated? Well, it’s not a trivial concept, but actually applying it is dead simple. Modifying the markup First thing is to place a class name on each li in the list:
Then, on each page of your site, apply the a matching class to the body tag to indicate which section of the site that page is in. For example, on your About page: ... Writing the CSS selector You can now write a single CSS rule to match the selected tab on any given page. The logic is that you want to match the ‘about’ tab on the ‘about’ page and the ‘products’ tab on the ‘products’ page, so the selector looks like this: body.home #navigation li.home, body.about #navigation li.about, body.work #navigation li.work, body.products #navigation li.products, body.contact #navigation li.contact{ ... whatever styles you need to show the tab selected ... } So all you need to do when you create a new page in your site is to apply a class to the body tag to say which section it’s in. The CSS will do the rest for you – without any server-side help.",2005,Drew McLellan,drewmclellan,2005-12-10T00:00:00+00:00,https://24ways.org/2005/auto-selecting-navigation/,code 319,Avoiding CSS Hacks for Internet Explorer,"Back in October, IEBlog issued a call to action, asking developers to clean up their CSS hacks for IE7 testing. Needless to say, a lot of hubbub ensued… both on IEBlog and elsewhere. My contribution to all of the noise was to suggest that developers review their code and use good CSS hacks. But what makes a good hack? Tantek Çelik, the Godfather of CSS hacks, gave us the answer by explaining how CSS hacks should be designed. In short, they should (1) be valid, (2) target only old/frozen/abandoned user-agents/browsers, and (3) be ugly. Tantek also went on to explain that using a feature of CSS is not a hack. Now, I’m not a frequent user of CSS hacks, but Tantek’s post made sense to me. In particular, I felt it gave developers direction on how we should be coding to accommodate that sometimes troublesome browser, Internet Explorer. But what I’ve found, through my work with other developers, is that there is still much confusion over the use of CSS hacks and IE. Using examples from the code I’ve seen recently, allow me to demonstrate how to clean up some IE-specific CSS hacks. The two hacks that I’ve found most often in the code I’ve seen and worked with are the star html bug and the underscore hack. We know these are both IE-specific by checking Kevin Smith’s CSS Filters chart. Let’s look at each of these hacks and see how we can replace them with the same CSS feature-based solution. The star html bug This hack violates Tantek’s second rule as it targets current (and future) UAs. I’ve seen this both as a stand alone rule, as well as an override to some other rule in a style sheet. Here are some code samples: * html div#header {margin-top:-3px;} .promo h3 {min-height:21px;} * html .promo h3 {height:21px;} The underscore hack This hack violates Tantek’s first two rules: it’s invalid (according to the W3C CSS Validator) and it targets current UAs. Here’s an example: ol {padding:0; _padding-left:5px;} Using child selectors We can use the child selector to replace both the star html bug and underscore hack. Here’s how: Write rules with selectors that would be successfully applied to all browsers. This may mean starting with no declarations in your rule! div#header {} .promo h3 {} ol {padding:0;} To these rules, add the IE-specific declarations. div#header {margin-top:-3px;} .promo h3 {height:21px;} ol {padding:0 0 0 5px;} After each rule, add a second rule. The selector of the second rule must use a child selector. In this new rule, correct any IE-specific declarations previously made. div#header {margin-top:-3px;} body > div#header {margin-top:0;} .promo h3 {height:21px;} .promo > h3 {height:auto; min-height:21px;} ol {padding:0 0 0 5px;} html > body ol {padding:0;} Voilà – no more hacks! There are a few caveats to this that I won’t go into… but assuming you’re operating in strict mode and barring any really complicated stuff you’re doing in your code, your CSS will still render perfectly across browsers. And while this may make your CSS slightly heftier in size, it should future-proof it for IE7 (or so I hope). Happy holidays!",2005,Kimberly Blessing,kimberlyblessing,2005-12-17T00:00:00+00:00,https://24ways.org/2005/avoiding-css-hacks-for-internet-explorer/,code 329,Broader Border Corners,"A note from the editors: Since this article was written the CSS border-radius property has become widely supported in browsers. It should be preferred to this image technique. A quick and easy recipe for turning those single-pixel borders that the kids love so much into into something a little less right-angled. Here’s the principle: We have a box with a one-pixel wide border around it. Inside that box is another box that has a little rounded-corner background image sitting snugly in one of its corners. The inner-box is then nudged out a bit so that it’s actually sitting on top of the outer box. If it’s all done properly, that little background image can mask the hard right angle of the default border of the outer-box, giving the impression that it actually has a rounded corner. Take An Image, Finely Chopped Add A Sprinkle of Markup

Lorem ipsum etc. etc. etc.

Throw In A Dollop of CSS #content { border: 1px solid #c03; } #content p { background: url(corner.gif) top left no-repeat; position: relative; left: -1px; top: -1px; padding: 1em; margin: 0; } Bubblin’ Hot The content div has a one-pixel wide red border around it. The paragraph is given a single instance of the background image, created to look like a one-pixel wide arc. The paragraph is shunted outside of the box – back one pixel and up one pixel – so that it is sitting over the div’s border. The white area of the image covers up that part of the border’s corner, and the arc meets up with the top and left border. Because, in this example, we’re applying a background image to a paragraph, its top margin needs to be zeroed so that it starts at the top of its container. Et voilà. Bon appétit. Extra Toppings If you want to apply a curve to each one of the corners and you run out of meaningful markup to hook the background images on to, throw some spans or divs in the mix (there’s nothing wrong with this if that’s the effect you truly want – they don’t hurt anybody) or use some nifty DOM Scripting to put the scaffolding in for you. Note that if you’ve got more than one of these relative corners, you will need to compensate for the starting position of each box which is nested in an already nudged parent. You’re not limited to one pixel wide, rounded corners – the same principles apply to thicker borders, or corners with different shapes.",2005,Patrick Griffiths,patrickgriffiths,2005-12-14T00:00:00+00:00,https://24ways.org/2005/broader-border-corners/,design 313,Centered Tabs with CSS,"Doug Bowman’s Sliding Doors is pretty much the de facto way to build tabbed navigation with CSS, and rightfully so – it is, as they say, rockin’ like Dokken. But since it relies heavily on floats for the positioning of its tabs, we’re constrained to either left- or right-hand navigation. But what if we need a bit more flexibility? What if we need to place our navigation in the center? Styling the li as a floated block does give us a great deal of control over margin, padding, and other presentational styles. However, we should learn to love the inline box – with it, we can create a flexible, centered alternative to floated navigation lists. Humble Beginnings Do an extra shot of ‘nog, because you know what’s coming next. That’s right, a simple unordered list:
If we were wedded to using floats to style our list, we could easily fix the width of our ul, and trick it out with some margin: 0 auto; love to center it accordingly. But this wouldn’t net us much flexibility: if we ever changed the number of navigation items, or if the user increased her browser’s font size, our design could easily break. Instead of worrying about floats, let’s take the most basic approach possible: let’s turn our list items into inline elements, and simply use text-align to center them within the ul: #navigation ul, #navigation ul li { list-style: none; margin: 0; padding: 0; } #navigation ul { text-align: center; } #navigation ul li { display: inline; margin-right: .75em; } #navigation ul li.last { margin-right: 0; } Our first step is sexy, no? Well, okay, not really – but it gives us a good starting point. We’ve tamed our list by removing its default styles, set the list items to display: inline, and centered the lot. Adding a background color to the links shows us exactly how the different elements are positioned. Now the fun stuff. Inline Elements, Padding, and You So how do we give our links some dimensions? Well, as the CSS specification tells us, the height property isn’t an option for inline elements such as our anchors. However, what if we add some padding to them? #navigation li a { padding: 5px 1em; } I just love leading questions. Things are looking good, but something’s amiss: as you can see, the padded anchors seem to be escaping their containing list. Thankfully, it’s easy to get things back in line. Our anchors have 5 pixels of padding on their top and bottom edges, right? Well, by applying the same vertical padding to the list, our list will finally “contain” its child elements once again. ’Tis the Season for Tabbing Now, we’re finally able to follow the “Sliding Doors” model, and tack on some graphics: #navigation ul li a { background: url(""tab-right.gif"") no-repeat 100% 0; color: #06C; padding: 5px 0; text-decoration: none; } #navigation ul li a span { background: url(""tab-left.gif"") no-repeat; padding: 5px 1em; } #navigation ul li a:hover span { color: #69C; text-decoration: underline; } Finally, our navigation’s looking appropriately sexy. By placing an equal amount of padding on the top and bottom of the ul, our tabs are properly “contained”, and we can subsequently style the links within them. But what if we want them to bleed over the bottom-most border? Easy: we can simply decrease the bottom padding on the list by one pixel, like so. A Special Note for Special Browsers The Mac IE5 users in the audience are likely hopping up and down by now: as they’ve discovered, our centered navigation behaves rather annoyingly in their browser. As Philippe Wittenbergh has reported, Mac IE5 is known to create “phantom links” in a block-level element when text-align is set to any value but the default value of left. Thankfully, Philippe has documented a workaround that gets that [censored] venerable browser to behave. Simply place the following code into your CSS, and the links will be restored to their appropriate width: /**//*/ #navigation ul li a { display: inline-block; white-space: nowrap; width: 1px; } /**/ IE for Windows, however, displays an extra kind of crazy. The padding I’ve placed on my anchors is offsetting the spans that contain the left curve of my tabs; thankfully, these shenanigans are easily straightened out: /**/ * html #navigation ul li a { padding: 0; } /**/ And with that, we’re finally finished. All set. And that’s it. With your centered navigation in hand, you can finally enjoy those holiday toddies and uncomfortable conversations with your skeevy Uncle Eustace.",2005,Ethan Marcotte,ethanmarcotte,2005-12-08T00:00:00+00:00,https://24ways.org/2005/centered-tabs-with-css/,code 332,CSS Layout Starting Points,"I build a lot of CSS layouts, some incredibly simple, others that cause sleepless nights and remind me of the torturous puzzle books that were given to me at Christmas by aunties concerned for my education. However, most of the time these layouts fit quite comfortably into one of a very few standard formats. For example: Liquid, multiple column with no footer Liquid, multiple column with footer Fixed width, centred Rather than starting out with blank CSS and (X)HTML documents every time you need to build a layout, you can fairly quickly create a bunch of layout starting points, that will give you a solid basis for creating the rest of the design and mean that you don’t have to remember how a three column layout with a footer is best achieved every time you come across one! These starting points can be really basic, in fact that’s exactly what you want as the final design, the fonts, the colours and so on will be different every time. It’s just the main sections we want to be able to quickly get into place. For example, here is a basic starting point CSS and XHTML document for a fixed width, centred layout with a footer. Fixed Width and Centred starting point document

Sidebar content here

Your main content goes here.

Ho Ho Ho!

body { text-align: center; min-width: 740px; padding: 0; margin: 0; } #wrapper { text-align: left; width: 740px; margin-left: auto; margin-right: auto; padding: 0; } #content { margin: 0 200px 0 0; } #content .inner { padding-top: 1px; margin: 0 10px 10px 10px; } #side { float: right; width: 180px; margin: 0; } #side .inner { padding-top: 1px; margin: 0 10px 10px 10px; } #footer { margin-top: 10px; clear: both; } #footer .inner { margin: 10px; } 9 times out of 10, after figuring out exactly what main elements I have in a layout, I can quickly grab the ‘one I prepared earlier’, mark-up the relevant sections within the ready-made divs, and from that point on, I only need to worry about the contents of those different areas. The actual layout is tried and tested, one that I know works well in different browsers and that is unlikely to throw me any nasty surprises later on. In addition, considering how the layout is going to work first prevents the problem of developing a layout, then realising you need to put a footer on it, and needing to redevelop the layout as the method you have chosen won’t work well with a footer. While enjoying your mince pies and mulled wine during the ‘quiet time’ between Christmas and New Year, why not create some starting point layouts of your own? The css-discuss Wiki, CSS layouts section is a great place to find examples that you can try out and find your favourite method of creating the various layout types.",2005,Rachel Andrew,rachelandrew,2005-12-04T00:00:00+00:00,https://24ways.org/2005/css-layout-starting-points/,code 324,Debugging CSS with the DOM Inspector,"An Inspector Calls The larger your site and your CSS becomes, the more likely that you will run into bizarre, inexplicable problems. Why does that heading have all that extra padding? Why is my text the wrong colour? Why does my navigation have a large moose dressed as Noel Coward on top of all the links? Perhaps you work in a collaborative environment, where developers and other designers are adding code? In which case, the likelihood of CSS strangeness is higher. You need to debug. You need Firefox’s wise-guy know-it-all, the DOM Inspector. The DOM Inspector knows where everything is in your layout, and more importantly, what causes it to look the way it does. So without further ado, load up any css based site in your copy of Firefox (or Flock for that matter), and launch the DOM Inspector from the Tools menu. The inspector uses two main panels – the left to show the DOM tree of the page, and the right to show you detail: The Inspector will look at whatever site is in the front-most window or tab, but you can also use it without another window. Type in a URL at the top (A), press ‘Inspect’ (B) and a third panel appears at the bottom, with the browser view. I find this layout handier than looking at a window behind the DOM Inspector. Step 1 – find your node! Each element on your page – be it a HTML tag or a piece of text, is called a ‘node’ of the DOM tree. These nodes are all listed in the left hand panel, with any ID or CLASS attribute values next to them. When you first look at a page, you won’t see all those yet. Nested HTML elements (such as a link inside a paragraph) have a reveal triangle next to their name, clicking this takes you one level further down. This can be fine for finding the node you want to look at, but there are easier ways. Say you have a complex rounded box technique that involves 6 nested DIVs? You’d soon get tired of clicking all those triangles to find the element you want to inspect. Click the top left icon © – “Find a node to inspect by clicking on it” and then select the area you want to inspect. Boom! All that drilling down the DOM tree has been done for you! Huzzah! If you’re looking for an element that you know has an ID (such as