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CSSCascading Style Sheets
Contents{
1. What is CSS? 1. A Brief History of CSS2. Why to use Styles?
2. Syntax 3. Cascading Order4. Examples of Properties5. Limitations6. CSS variations
{What is CSS? CSS stands for Cascading Style Sheets Styles define how to display (X)HTML elements Styles are normally stored in Style Sheets Multiple style definitions will cascade into one
{A Brief History of CSS
Style sheets have existed since the beginnings of SGML in the 1970s
As HTML grew, it came to encompass a wider variety of stylistic capabilities
Nine different style sheet languages were proposed to the W3C
Two were chosen as the foundation for CSS: CHSS and Stream-based Style Sheet Proposal
CSS level 1 – 1996; CSS level 2 – 1997 Difficulties with adoption
{Why to use Styles? Documents written with CSS are
more flexible short clear
Basic formating tool Easy multiple document managment Save time by using selector classes New opportunities in formating
Syntax
CSS
{ Basic Syntax Made up of three parts:selector {property: value}
The selector is normally the HTML element/tag you wish to define
The property is the attribute you wish to change Every property has the value
{ Syntax If the value is multiple words, put quotes around the
valuep {font-family: "sans serif"}
To make the style definitions more readable, you can describe one property on each line
p { text-align: center; color: black; font-family: arial }
{ Grouping
h1,h2,h3,h4,h5,h6 { color: green }
All header elements will be displayed in green text color
This is header h1This is header h2This is header h3This is header h4
{ The class Selector
With the class selector you can define different styles for the same type of HTML element.p.right {text-align: right} p.center {text-align: center}
Using the class argument in (X)HTML:<p class="right"> This paragraph will be right-aligned. </p>
<p class="center"> This paragraph will be center-aligned. </p>
{ Text color
<html><head>
<style type="text/css">
h1 {color: green}
h2 {color: #dda0dd}
p {color: rgb(0,0,255)}
</style>
</head>
<body>
<h1>This is header 1</h1>
<h2>This is header 2</h2>
<p>This is a paragraph</p>
</body>
</html>
This is header 1This is header 2This is a paragraph
Inserting of style sheet
CSS
{Cascading order
1. Browser default2. External style sheet
inside external *.css file
3. Internal style sheet inside the <head> tag
4. Inline style inside an HTML element
{External Style Sheet Each webpage must link
to the style sheet using the <link> tag
Browser reads styles definitions from mystyle.css file
<head> <link rel="stylesheet" type="text/css" href="mystyle.css" />
</head>
{ Internal Style Sheet Should be used when a
single document has a unique style
Defined in the head section by using the <style> tag
<head>
<style type="text/css">
hr {color: sienna}
p {margin-left: 20px}
body {background-image: url("images/back40.gif")}
</style>
</head>
{ Multiple Style Sheets An internal style sheet has
following properties for the h3 selector:h3 { text-align: right;
font-size: 20pt } External style sheet has
these:h3 { color: red; text-align: left; font-size: 8pt }
Your Web Browser has default formatting:h3 { color: black; font size: 10pt }
What will be the format of <h3> tag?
o color: red;o text-align: right; o font-size: 20pt
Examples
CSS Properties & values
{ Background: Control over the
background color of an element
set an image as the background,
repeat a background image
background-color color-rgbcolor-hexcolor-name
background-image url(URL)none
background-repeat repeatrepeat-xrepeat-yno-repeat
{Text: color direction
ltrrtl
word spacing normallength
text-decoration noneunderlineoverlineline-throughblink
text-align leftrightcenterjustify
{Font: font-family• family-namegeneric-family
font-size xx-smallx-smallsmall
/etc./
font-weigh normalboldbolderlighter100
{Dimension
{List:<head><style type="text/css">ul {list-style-image: url('arrow.gif')
}</style></head>
<body><ul> <li>Coffee</li> <li>Tea</li> <li>Coca Cola</li></ul>
</body>
CSS
Variations, Limitations
{CSS Limitations Some noted disadvantages of using "pure" CSS include
Inconsistent browser support Absence of expressions Lack of Variables Lack of multiple backgrounds per element Control of Element Shapes
CSS level 1 The first CSS specification to become an official W3C
Recommendation is CSS level 1, published in December 1996. Among its capabilities are support for: Font properties such as typeface and emphasis Color of text, backgrounds, and other elements Text attributes such as spacing between words, letters, and
lines of text Alignment of text, images, tables and other elements Margin, border, padding, and positioning for most elements Unique identification and generic classification of groups of
attributes The W3C maintains the CSS1 Recommendation.
CSS level 2 published as a Recommendation in May 1998. includes a number of new capabilities
absolute, relative, and fixed positioning of elements the concept of media types bidirectional text new font properties such as shadows
The W3C maintains the CSS2 Recommendation. CSS level 2 revision 1 or CSS 2.1 fixes errors in CSS2
returned to Candidate Recommendation status on 19 July 2007
Useful links http://www.w3schools.com/css/
Learn CSS http://validator.w3.org/
Check Your CSS syntax http://www.csszengarden.com/
The beauty of CSS Design One HTML file 210 CSS
http://www.csszengarden.com/
http://www.csszengarden.com/?cssfile=/209/209.css
http://www.csszengarden.com/?cssfile=/207/207.css
http://www.csszengarden.com/?cssfile=192/192.css
Zen Garden without formatting
Thank You for Your Attention
CSS
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