1. CSS
Cascading Style Sheets

2. Style Sheets
Describe the evolution of style sheets from print media to the web
List advantages of using cascading style sheets
Create style sheets that configure common page and text properties
Use inline styles
Use embedded style sheets
Use external style sheets
Use pseudo-classes

3. Overview of Cascading Style Sheets (CSS)
See what is possible with CSS:
Visit
Style Sheets
used for years in Desktop Publishing
apply typographical styles and spacing to printed media
CSS
provides the functionality of style sheets (and much more) for web developers
a flexible, cross-platform, standards-based language developed by the W3C.

4. CSS Advantages Greater typography and page layout control
Style is separate from structure
Styles can be stored in a separate document and linked to from the web page
Potentially smaller documents
No need for <font> tags
Easier site maintenance

5. Types of Cascading Style Sheets
Inline Styles
Inline styles are coded in the body of the web page as an attribute of an XHTML tag. The style only applies to the specific element that contains it as an attribute
Embedded Styles
Embedded styles are defined in the header of a web page. These style instructions apply to the entire web page document.
External Styles
External Styles are coded in a separate text file. This text file is linked to the web page by using a <link> tag in the header section.
Imported Styles
Imported Styles are similar to External Styles in that they are coded in a separate text file. We’ll concentrate on the other types of styles in this text.

6. CSS Syntax
Style sheets are composed of "Rules" that describe the styling to be applied.
Each Rule contains a Selector and a Declaration

7. CSS Syntax Sample body { color: blue; background-color: yellow; }
This could also be written using hexadecimal color values as shown below.
body { color: #0000FF;
background-color: #FFFF00; }

8. Common Formatting CSS Properties
See Table 9.1 Common CSS Properties, including:
background-color
color
font-family
font-size
font-weight
font-style
text-decoration
line-height
text-align
background-image

9. Using Inline Styles
Inline Styles are coded as attributes on XHTML tags.
The following code will set the text color of a <h1> tag to a shade of red:
<h1 style="color:#CC0000">This is displayed as a red heading</h1>
The following code sets the text in the heading to red and italic.
<h1 style="color:#CC0000;font-style:italic">This is displayed as a red heading in italic style</h1>

10. Hexadecimal Color Values
# is used to indicate a hexadecimal value
Hex value pairs range from 00 to FF
Three hex value pairs describe an RGB color
# black #FFFFFF white
#FF0000 red #00FF00 green
#0000FF blue #CCCCCC grey

11. Configuring Color with Inline CSS (1)
Configured in the body of the Web page
Use the style attribute of an XHTML tag
Apply only to the specific element
The Style Attribute
Value: one or more style declaration property and value pairs
Example: configure red color text in an <h1> element:
<h1 style="color:#ff0000">Heading text is red</h1>

12. Configuring Color with Inline CSS (2)
Example 2: configure the red text in the heading
configure a gray backgroundin the heading
Separate style rule declarations with ;
<h1 style="color:#FF0000;background-color:#cccccc">This is displayed as a red heading with gray background</h1>

13. Questions List three reasons to use CSS on a web page.
When designing a page to use other than the default colors for text and background, explain why it is a good reason to configure both properties: text color and background color.
Write the code to configure an inline style attached to a <div> tag. Configure as follows: background color set to a light green color, text set to a dark green color, font set to Arial or sans-serif, size set to larger, font weight set to bold.

14. CSS Embedded Styles Configured in the header section of a Web page.
Use the XHTML <style> element
Apply to the entire Web page document
Style declarations are contained between the opening and closing <style> tags
The type attribute indicates the MIME type of text/css
Example: Configure a Web page with white text on a black background
<style type ="text/css">
body { background-color: #000000;
color: #FFFFFF; }
</style>

15. Embedded Styles <style type="text/css">
body { background-color: #000000;
color: #FFFFFF;
font-family:Arial,sans-serif; }
</style>
Embedded Styles
Apply to an entire web page.
Placed within a <style> tag located in the header section of a web page.
The opening <style> tag begins the embedded style rules.
The closing </style> tag ends the area containing embedded style rules.
When using the <style> tag, there is no need for the style attribute.
The <style> tag does use a type attribute that should have the value of "text/css".

16. CSS Embedded Styles
The body selector sets the global style rules for the entire page.
These global rules are overridden for <h1> and <h2> elements by the h1 and h2 style rules.
<style type="text/css"> body { background-color: #E6E6FA; color: #191970;} h1 { background-color: #191970; color: #E6E6FA;} h2 { background-color: #AEAED4; </style>

17. CSS and text

18. Configuring Text with CSS
CSS properties for configuring text:
font-weight
Configures the boldness of text
font-style
Configures text to an italic style
font-size
Configures the size of the text
font-family
Configures the font typeface of the text

19. The font-size Property
Accessibility Recommendation:
Use em or percentage font sizes – these can be easily enlarged in all browsers by users

20. The font-family Property
Not everyone has the same fonts installed in their computer
Configure a list of fonts and include a generic family name
p {font-family: Arial,Verdana, sans-serif;}

21. Embedded Styles Example
<style type="text/css">
body { background-color: #E6E6FA;
color: #191970;
font-family: Arial, Verdana, sans-serif; }
h1 { background-color: #191970;
color: #E6E6FA;
line-height: 200%;
font-family: Georgia, "Times New Roman", serif; }
h2 { background-color: #AEAED4;
font-family: Georgia, "Times New Roman", serif; }
p {font-size: .90em; }
ul {font-weight: bold; }
</style>

22. CSS Selectors CSS style rules can be configured for an:
HTML element selector (i.e. as we saw in previous slide to the element itself)
class selector
id selector

23. Using CSS with “class” class Selector Configure with .classname
Apply a CSS rule to a certain "class" of elements on a Web page
Does not associate the style to a particular XHTML element
Configure with .classname
The sample creates a class called “new” with red italic text.
To use the class, code the following XHTML:
<p class=“new”>This is text is red and in italics</p>
<style type="text/css">
.new { color: #FF0000;
font-style: italic; }
</style>

24. Using CSS with “id” id Selector Configure with #idname
Apply a CSS rule to ONE element on a Web page.
Configure with #idname
The sample creates an id called “new” with red, large, italic text.
To use the id, code the following XHTML:
<p id=“new”>This is text is red, large, and in italics</p>
<style type="text/css">
#new { color: #FF0000;
font-size:2em;
font-style: italic; }
</style>

25. Why ID and class
SPECIAL question ---why both id and classname used to define CSS embeded styles:
ID's are unique
Each element can have only one ID
Each page can have only one element with that ID
Classes are NOT unique
You can use the same class on multiple elements.
You can use multiple classes on the same element.

26. CSS and styling “areas”

27. XHTML <div> element
A block-level element
Purpose: configure a specially formatted division or area of a Web page
There is a line break before and after the division.
Can contain other block-level and inline elements
Useful to define an area that will contain other block-level tags (such as paragraphs or spans) within it.

28. XHTML <div> Element Example
Configure a page footer area
Embedded CSS:
<style type="text/css">
.footer { font-size: small;
text-align: center; }
</style>
XHTML:
<div class=“footer">Copyright © 2009</div>

29. XHTML <span> element
An inline-level element
Purpose:
configure a specially formatted area displayed in-line with other elements, such as within a paragraph.
There is no line break before and after the span.

30. XHTML <span> Element Example
Embedded CSS:
<style type="text/css">
.companyname { font-weight: bold;
font-family: Georgia, "Times New Roman", serif;
font-size: 1.25em; }
</style>
XHTML:
<p>Your needs are important to us at <span class=“companyname">Acme Web Design</span>. We will work with you to build your Web site.</p>

31. External Style Sheets
Storing in separate file – decoupling design from content!!!
NOTE: IDEs like Dreamweaver often do this by default

32. External Style Sheets
CSS style rules are contained in a text file separate from the XHTML documents.
The External Style Sheet text file:
extension ".css"
contains only style rules
does not contain any XHTML tags

33. External Style Sheets
Multiple web pages can associate with the same external style sheet file.
index.htm
site.css
body {background-color:#E6E6FA;
color:#000000;
font-family:Arial, sans-serif;
font-size:90%; }
h2 { color: #003366; }
.nav { font-size: 16px;
font-weight: bold; }
clients.htm
about.htm
Etc…

34. The <link /> Element
A self-contained tag
Placed in the header section
Purpose: associates the external style sheet file with the web page.
Example:
<link rel="stylesheet" href="color.css" type="text/css" />

35. Using an External Style Sheet
External Style Sheet color.css
body { background-color: #0000FF;
color: #FFFFFF; }
To link to the external style sheet called color.css, the XHTML code placed in the header section is: <link rel="stylesheet" href="color.css" type="text/css" />

36. Centering Page Content with CSS
#container { margin-left: auto; margin-right: auto; width:80%; }

37. W3C CSS Validation

38. CSS Guidelines – Getting Started
Review the design of the page
Configure global font and color properties for the body selector
Identify typical elements (such as <h1>, <h3>, and so on) and declare style rules for these if needed.
Identify page areas such as logo, navigation, footer, and so on – configure an appropriate class or id for each.
Create one prototype page that contains most of the elements you plan to use and test.
Revise your CSS as needed.
Once your design is set – move styles to an external .css file
Planning and testing are important activities when designing a Web site

39. CSS Troubleshooting Tips
Verify you are using the : and ; symbols in the right spots—they are easy to confuse.
Check that you are not using = signs instead of : between each property and its value.
Verify that the { and } symbols are properly placed
Check the syntax of your selectors, their properties, and property values for correct usage.
If part of your CSS works, and part doesn’t:
Review your CSS
Determine the first rule that is not applied. Often the error is in the rule above the rule that is not applied.
Validate your CSS at

40. The Cascade
This “cascade” applies the styles in order from outermost (External Styles) to innermost (actual XHTML coded on the page).
This way site-wide styles can be configured but overridden when needed by more granular (or page specific) styles.

41. CSS and anchor <a> tag
Style attributes differently
Use to make buttons

42. CSS Pseudo-classes Pseudo-classes and the anchor tag
<style type=”text/css>
a:link {color:#FF0000 }
a:hover {text-decoration:none;
color:# }
</style>
CSS Pseudo-classes
Pseudo-classes and the anchor tag
Link – default state for a link (anchor tag)
Visited – state of a link that has been visited
Hover – state of a link that the mouse is currently over
Active – state of a link that is being clicked

43. CSS “buttons” <style type="text/css">
.button { border: 2px inset #cccccc;
width: 100px;
padding: 3px 15px;
color: #ffffff;
background-color: #006600;
font-family: Arial, Helvetica, sans-serif;
font-size: 16px;
font-weight: bold;
text-align: center;
text-decoration:none; }
a.button:link { color : #FFFFFF; }
a.button:visited { color : #cccccc; }
a.button:hover { color : #66cc33;
border:2px outset #cccccc;
</style>
CSS “buttons”
<div align="center">
<h2>CSS Buttons!</h2>
<a href="index.htm" class="button">Home</a>
<a href="products.htm" class="button">Products</a>
<a href="sevices.htm" class="button">Services</a>
<a href="contact.htm" class="button">Contact</a>
<a href="about.htm" class="button">About</a>
<div>

44. CSS – more to do
Effecting borders

45. The CSS border Property
Configures a border on the top, right, bottom, and left sides of an element
Consists of
border-width
border-style
border-color
h2 { border: 2px solid #ff0000 }

46. CSS Borders: Block / Inline Elements
Block element
default width of element content extends to browser margin (or specified width)
Inline element
Border closely outlines the element content
h2 { border: 2px solid #ff0000; }
a { border: 2px solid #ff0000; }

47. Browser Display Can Vary

48. Configuring Specific Sides of a Border
Use CSS to configure a line on one or more sides of an element
border-bottom
border-left
border-right
border-top
h2 { border-bottom: 2px solid #ff0000 }

49. The CSS padding Property
Configures empty space between the content of the XHTML element and the border
Set to 0px by default
h2 { border: 2px solid #ff0000;
padding: 5px; }
No padding configured:

50. Configuring Padding on Specific Sides of an Element
Use CSS to configure padding on one or more sides of an element
padding-bottom
padding-left
padding-right
padding-top
h2 { border: 2px solid #ff0000;
background-color: #cccccc;
padding-left: 5px;
padding-bottom: 10px;
padding-top: 10px;}

51. CSS padding Property Shorthand: two values
Two numeric values or percentages
first value configures top and bottom padding
the second value configures left and right padding
h2 { border: 2px solid #ff0000;
background-color: #cccccc;
padding: 20px 10px; }

52. CSS padding Property Shorthand: four values
Four numeric values or percentages
Configure top, right, bottom, and left padding
h2 { border: 2px solid #ff0000;
width: 250px;
background-color: #cccccc;
padding: 30px 10px 5px 20px; }

53. Hands-On Practice
Try this on your own
h1 { background-color:#191970; color:#E6E6FA; padding: 15px; font-family: Georgia, "Times New Roman", serif; } h2 { background-color:#AEAED4; color:#191970; font-family: Georgia, "Times New Roman", serif; border-bottom: 2px dashed #191970; }

54. CSS – more to do
Background images

55. CSS background-image Property
Configures a background-image
By default, background images tile (repeat)
body { background-image: url(background1.gif); }

56. CSS background-repeat Property

57. Using background-repeat
trilliumbullet.gif:
h2 { background-color: #d5edb3; color: #5c743d; font-family: Georgia, "Times New Roman", serif; padding-left: 30px; background-image: url(trilliumbullet.gif); background-repeat: no-repeat; }

58. CSS Strategies(1)
Always include end tags (even though browsers usually display the page, anyway) for all XHTML container tags.
Design and code the page to look "OK" or "Acceptable" -- then use style sheets for extra-special effects and formatting.
Use style sheet components that will degrade gracefully. Check the compatibility charts and test, test, test, test, test....

59. CSS Strategies(2)
Use <div> and <span> tags to create logical page sections. Be aware that Netscape 4.x handles the <div> tag better than the <span> tag.
Use style sheets in Intranet environments -- you know exactly what browsers your visitors will be using.
Consider using a browser detection script (discussed in Chapter 12) to test for a specific browser and link to the style sheet coded specifically for that browser.