Cascading CSS can potentially cause problems with encapsulation, which means that other page styles may affect or conflict with the navbar and menu styles:
Since the navigation bar and
menus are made of HTML
they'll be affected by global styles applying to
<ul>, <li> and <a> elements.
The menu also uses <span> and <img> to create
menu-indicators, and <h*>
if you have
headings inside the navbar.
In practice, <a> elements are so well-defined that it's extremely
unlikely you'll get any problems. But for the others you might, so
there's a few things you can do to minimize the
chances of conflict:
<div> with
the id of "content", you can use a descendent selector
from that: "#content ul { }"
rather than simply "ul { }".
"#udm a { text-decoration:none !important; }".
The links have dynamic z-index, which continually
increases and requires up to
20,000 levels of headroom. If you want other elements
to go above the navigation, you'll need to position
them with a higher z-index value: 20000 plus
whatever you've defined for the
navbar's base z order.
You shouldn't have other elements whose class name begins or ends with "udm", because the menu uses CSS3 substring-matching attribute selectors to apply certain styles, for example:
ul[class^="udm"] {
...
}
This will match any element who's class name
begins with "udm" (and another selector is used
which will match it at the end of a string). So to avoid problems,
don't begin or end other class names with that substring.
UDM 4 is valid XHTML, and in our judgement, meets the criteria for WAI Triple-A conformance.