s.\n\n

\n\n #one { \n position: relative; \n z-index: 3;\n }\n\n #two { \n position: relative; \n z-index: 1;\n }\n\n #three {\n position: relative; \n z-index: 2;\n }\n\n\n\nAs you can see, the

with the z-index of 3 will appear closest, even though it comes before its siblings in the source order. As these three

s have no defined positioning context in the form of a positioned parent such as a

, their stacking order is defined from the root element . Simple stuff, but these building blocks are the basis on which we can create interesting interfaces (particularly when used in combination with image replacement and transparent PNGs).\n\nBrand building\n\nNow let\u2019s take three more basic elements, an

,
and
, all inside a branding
which acts a new positioning context. By enclosing them inside a positioned parent, we establish a new stacking order which is independent of either the root element or other positioning contexts on the page.\n\n
\n
Worrysome.com
\n
Don' worry 'bout a thing...
\n
Take the weight of the world off your shoulders.
\n
\n\nApplying a little positioning and z-index magic we can both set the position of these elements inside their positioning context and their stacking order. As we are going to use background images made from transparent PNGs, each element will allow another further down the stacking order to show through. This makes for some novel effects, particularly in liquid layouts.\n\n(Ed: We\u2019re using n below to represent whatever values you require for your specific design.) \n\n#branding {\n position: relative;\n width: n;\n height: n;\n background-image: url(n);\n }\n\n #branding>h1 {\n position: absolute;\n left: n;\n top: n;\n width: n;\n height: n;\n background-image: url(h1.png);\n text-indent: n;\n }\n\n #branding>blockquote {\n position: absolute;\n left: n;\n top: n;\n width: n;\n height: n;\n background-image: url(bq.png);\n text-indent: n;\n\n }\n\n #branding>p {\n position: absolute;\n right: n;\n top: n;\n width: n;\n height: n;\n background-image: url(p.png);\n text-indent: n;\n }\n\nNext we can begin to see how the three elements build upon each other.\n\n\n1. Elements outlined\n\n\n2. Positioned elements overlayed to show context\n\n\n3. Our final result\n\nMultiple stacking orders\n\nNot only can elements within a positioning context be given a z-index, but those positioning contexts themselves can also be stacked.\n\n\nTwo positioning contexts, each with their own stacking order\n\nInterestingly each stacking order is independent of that of either the root element or its siblings and we can exploit this to make complex layouts from just a few semantic elements. This technique was used heavily on my recent redesign of Karova.com.\n\nDissecting part of Karova.com\n\nFirst the XHTML. The default template markup used for the site places
and
as siblings inside their container.\n\n
\n
\n
\n
\n
\n
\n
\n\nBy giving the navigation
a lower z-index than the content
we can ensure that the positioned content elements will always appear closest to the viewer, despite the fact that the navigation comes after the content in the source.\n\n#content { \n position: relative; \n z-index: 2; \n }\n\n #nav_main { \n position: absolute; \n z-index: 1; \n }\n\nNow applying absolute positioning with a negative top value to the
and a higher z-index value than the following
ensures that the header sits not only on top of the navigation but also the styled paragraph which follows it.\n\nh2 {\n position: absolute;\n z-index: 200;\n top: -n;\n }\n\n h2+p {\n position: absolute;\n z-index: 100;\n margin-top: -n;\n padding-top: n;\n }\n\n\nDissecting part of Karova.com\n\nYou can see the full effect in the wild on the Karova.com site.\n\nHave a great holiday season!", "year": "2005", "author": "Andy Clarke", "author_slug": "andyclarke", "published": "2005-12-16T00:00:00+00:00", "url": "https://24ways.org/2005/zs-not-dead-baby-zs-not-dead/", "topic": "design"} {"rowid": 329, "title": "Broader Border Corners", "contents": "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.\n \n \n \n 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.\n\nHere\u2019s 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\u2019s actually sitting on top of the outer box. If it\u2019s 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.\n\nTake An Image, Finely Chopped\n\n\n\nAdd A Sprinkle of Markup\n\n
\n
Lorem ipsum etc. etc. etc.
\n
\n\nThrow In A Dollop of CSS\n\n#content { \n border: 1px solid #c03;\n}\n\n#content p {\n background: url(corner.gif) top left no-repeat;\n position: relative;\n left: -1px;\n top: -1px;\n padding: 1em;\n margin: 0;\n}\n\nBubblin\u2019 Hot\n\n\n\tThe content div has a one-pixel wide red border around it.\n\tThe paragraph is given a single instance of the background image, created to look like a one-pixel wide arc.\n\tThe paragraph is shunted outside of the box \u2013 back one pixel and up one pixel \u2013 so that it is sitting over the div\u2019s border. The white area of the image covers up that part of the border\u2019s corner, and the arc meets up with the top and left border.\n\tBecause, in this example, we\u2019re applying a background image to a paragraph, its top margin needs to be zeroed so that it starts at the top of its container.\n\n\nEt voil\u00e0. Bon app\u00e9tit.\n\nExtra Toppings\n\n\n\tIf 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\u2019s nothing wrong with this if that\u2019s the effect you truly want \u2013 they don\u2019t hurt anybody) or use some nifty DOM Scripting to put the scaffolding in for you.\n\tNote that if you\u2019ve 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.\n\tYou\u2019re not limited to one pixel wide, rounded corners \u2013 the same principles apply to thicker borders, or corners with different shapes.", "year": "2005", "author": "Patrick Griffiths", "author_slug": "patrickgriffiths", "published": "2005-12-14T00:00:00+00:00", "url": "https://24ways.org/2005/broader-border-corners/", "topic": "design"} {"rowid": 330, "title": "An Explanation of Ems", "contents": "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:\n\n\n\tThe 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.\n\n\nTo illustrate this principle in terms of CSS, consider these styles:\n\n#box1 {\n font-size: 12px;\n width: 1em;\n height: 1em;\n border:1px solid black;\n}\n\n#box2 {\n font-size: 60px;\n width: 1em;\n height: 1em;\n border: 1px solid black;\n}\n\nThese styles will render like:\n\n M\n\nand\n\n M\n\nNote 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.", "year": "2005", "author": "Richard Rutter", "author_slug": "richardrutter", "published": "2005-12-02T00:00:00+00:00", "url": "https://24ways.org/2005/an-explanation-of-ems/", "topic": "design"}