10.1 CSS Overview

Conceptually, CSS is pretty simpleyou define styles that can be applied easily over one or more pages. But the details can get confusing unless you're familiar with the terminology ( especially because Dreamweaver's terminology varies slightly from that used elsewhere). We'll start with the big picture and work our way towards the details.

10.1.1 CSS Versus HTML Styles

First let's compare CSS to so-called HTML styles (discussed in Chapter 11).

CSS stylesheets:

  • Are managed using the CSS Styles panel (see Figure 10-15), the Edit Style Sheet dialog box, the New Style dialog box, and the Style Definition dialog box. The CSS Styles panel shows only the styles available in the current document.

  • Require browsers supporting CSS1 (or later). Therefore, CSS generally works only in 4.0 browsers or later (see Table 10-1). CSS code is not HTML, but can be stored in an HTML page within <style> tags or within style="" attributes associated with other elements.

  • Offer advanced and precise control over all aspects of page formatting, including paragraph formatting, image alignment, margins, spacing, borders, element positioning, and special effects.

  • Offer automatic updating; if a CSS style changes, all content that uses the style will be updated automatically.

  • Use a compact and efficient notation. Multiple HTML pages can use a single stylesheet. CSS defines rules for the application of conflicting styles.

  • Doesn't distinguish between character and paragraph formatting.

  • Are based on a W3C standard.

HTML styles:

  • Are managed using the HTML Styles panel (see Chapter 11). The styles in the HTML Styles panel are accessible to all pages on a site.

  • Offer compatibility with older browsers (IE3, NN3, and earlier) that do not support CSS. HTML styles are a convenience offered in Dreamweaver, but they use basic HTML tags that don't require special browser features.

  • Offer imprecise control over fonts and little control over many page-formatting options.

  • Must be manually reapplied if a style changes (i.e., no automatic updating).

  • Suffer from verbose notation; multiple pages cannot share common styles.

  • Distinguish between character and paragraph formatting, similar to MS Word.

  • Are an invented convenience offered by Macromedia.

10.1.2 CSS and Browsers

Table 10-1 shows the level of CSS support in the major browsers. Although you'll need Version 4 or later for CSS1 support, even 4.x browsers don't necessarily implement all the CSS1 rules. Notable exceptions are highlighted where applicable . See the compatibility matrix of CSS property support at http://www.webreview.com/style/css1/ charts /mastergrid.shtml.

Table 10-1. CSS support in major browsers

CSS Support



IE2 and earlier; NN 3 and earlier

Partial CSS1 support



IE4 or later; NN4 (has some bugs ); Opera 4 and later

CSS1 and CSS2

IE5.5 or later; NN6 or later; Opera 5

10.1.3 CSS Roadmap

You need to understand several important concepts when using CSS styles in Dreamweaver, and they can't all be covered immediately. For example, I intentionally defer discussing how to apply CSS styles because the method depends on the type of CSS styles you've defined. Once you understand the nuances of CSS styles, you'll know how to apply them and why. Figure 10-1 gives you a roadmap to this chapter so you can decide in which order you'll read the sections. Buckle up! It's a long ride, but worth the trip.

Figure 10-1. CSS styles roadmap

As you can see, there is a lot going on in Figure 10-1, so let's take a closer look at the life cycle of a CSS style (creation, storage, and application):

  1. New styles are created using the New Style dialog box as seen in Figure 10-5 (Text figs/u2192.gif CSS Styles figs/u2192.gif New Style), which leads to the Style Definition dialog box (Figures Figure 10-7 through Figure 10-14).

  2. Styles defined in the Style Definition dialog box are deposited either in the HTML document or an external file. Embedded styles are stored within the HTML file itself; external stylesheets are separate .css files.

  3. Custom CSS styles, known as class selectors (such as .caption and .subhead2 ) are shown in the CSS Styles panel (Figure 10-15); type selectors that redefine existing HTML tags, such as p , are not.

  4. Both embedded styles and styles from external stylesheets can be used to format the HTML document's body content.

  5. The Edit Style Sheet dialog box (Figure 10-2) lists embedded styles individually (including ones that don't show up in the CSS Styles panel), but lists only the filenames of external stylesheetsnot the styles within them.

  6. Highlighting an external stylesheet's filename in the Edit Style Sheet dialog box and clicking the Edit button opens another dialog box that lists all the styles in an external stylesheet (see Figure 10-4). To actually edit a style, click the Edit button to go back to the Style Definition dialog box (see Step 2 of this list).

We'll cover these topics in the following sections:

  • Section 10.2 summarizes such operations as defining, applying, and editing styles and stylesheets.

  • Section 10.3 explains where styles are storednamely embedded in the HTML document or in external stylesheets (in a separate external .css file).

  • Section 10.4 covers details on the syntax of styles themselves and describes the different kinds of styles you're likely to use (custom classes, styles that redefine an HTML tag, and CSS selectors). We'll explain how to define new styles and store them in the embedded stylesheet or in a new or existing external stylesheet.

  • Section 10.5 covers the eight different panes in the Style Definition dialog box that can be used to set the properties for your style.

  • Section 10.6 covers how the CSS Styles panel is used to manage and apply styles.

  • Section 10.7 revisits some dialog boxes and explains how to revise existing styles and stylesheets.

  • Section 10.8.1 talks about precedence of styles and resolving potentially conflicting styles.

  • Section 10.8.2 and Section 10.8.3 cover some advanced topics.

Dreamweaver in a Nutshell
Dreamweaver in a Nutshell
Year: 2005
Pages: 208

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