As a web developer, I have this pocket reference in my backpack at all times. It’s invaluable to how I make my living…

If you have not learned how to use CSS – and all the different things CSS can be used upon/within – then you are really missing out. This goes for whether your fancy yourself a web designer or claim to be a programmer.

Web UIs are pervasive these days. Today, many applications embed what is loosely called “web technology”. This includes CSS and some standard document format(s) on which it can apply its style rules.

The list of document types CSS 2.1 can style is growing:

1. HTML (the old workhorse from the early 1990s – Java Swing components even support it)
2. XHTML (like HTML but pretty much cleaner/better in small but meaningful ways since it follows the simple/consistent XML syntax rules)
3. XML (yes, it can style plain, old XML elements, just set the display: attribute for each of them)
4. SVG (you have heard of graphics, haven’t you?)
5. XForms (the standard way of displaying forms/controls in XHTML 2.0 is also a modular standard that can be used standalone or with other document formats besides XHTML)
6. MathML (even mathematicians have style to their writing)

Java has had the ability to display HTML, and a little CSS, in its Java GUI applications since the late 1990s.

Java application programs can also embed a web server such as Tomcat. It is no big deal. The capability has been there for half a decade.

So anyone programming Java – client or server applications – should learn CSS and one or more of the document languages mentioned above.

Web designers are moving away from deeply nested tables for doing layouts. The only hygienic way to do precision layouts these days is with CSS. Tables have their place – but they do not own the place anymore.