Css presentation lecture 1

CSS
Muhammad Ali Baloch
6/16/2013 Hidaya Institute Of Science And Technology Jamshoro 1

TOPIC ‘s TO BE COVERED
• CSS Introduction
• CSS Syntax – Selectors
• CSS Inclusion - Associating Styles
• Setting Backgrounds using CSS
• Setting Fonts using CSS
• Manipulating Text using CSS
• CSS – Images
• CSS – Links
• CSS – Box Model

CSS INTRODUCTION
What is CSS …?

CSS INTRODUCTION
• Cascading Style Sheets, fondly referred to as CSS, is a simple design language intended to
simplify the process of making web pages presentable.
• CSS handles the look and feel part of a web page. Using CSS, you can control the color of the
text, the style of fonts, the spacing between paragraphs, how columns are sized and laid out,
what background images or colors are used, as well as a variety of other effects.
• CSS is easy to learn and understand but it provides powerful control over the presentation of
an HTML document. Most commonly, CSS is combined with the markup languages HTML or
XHTML.

CSS INTRODUCTION (Advantages of CSS)
• CSS SAVE TIME
• You can write CSS once and then reuse same sheet in multiple HTML pages. You can define a
style for each HTML element and apply it to as many Web pages as you want.
• PAGES LOAD FASTER
• If you are using CSS, you do not need to write HTML tag attributes every time. Just write one
CSS rule of a tag and apply to all the occurrences of that tag. So less code means faster
download times.
• EASY MAINTENANCE
• To make a global change, simply change the style, and all elements in all the web pages will
be updated automatically.

CSS INTRODUCTION (Advantages of CSS)
• SUPERIOR STYLES TO HTML
• CSS has a much wider array of attributes than HTML so you can give far better look to your
HTML page in comparison of HTML attributes.
• MULTIPLE DEVICE COMPATIBILITY
• Style sheets allow content to be optimized for more than one type of device. By using the
same HTML document, different versions of a website can be presented for handheld devices
such as PDAs and cell phones or for printing.
• GLOBAL WEB STANDARDS
• Now HTML attributes are being deprecated and it is being recommended to use CSS. So its a
good idea to start using CSS in all the HTML pages to make them compatible to future
browsers.

CSS INTRODUCTION (Who Creates and Maintains CSS)
• CSS is created and maintained through a group of people within the W3C called the CSS Working
Group. The CSS Working Group creates documents called specifications. When a specification has
been discussed and officially ratified by W3C members, it becomes a recommendation.
• These ratified specifications are called recommendations because the W3C has no control over
the actual implementation of the language. Independent companies and organizations create that
software.
• NOTE: The World Wide Web Association, or W3C is a group that makes recommendations about
how the Internet works and how it should evolve.

CSS INTRODUCTION (CSS Versions)
• Cascading Style Sheets, level 1 (CSS1) was came out of W3C as a recommendation in December
1996. This version describes the CSS language as well as a simple visual formatting model for all
the HTML tags.
• CSS2 was became a W3C recommendation in May 1998 and builds on CSS1. This version adds
support for media-specific style sheets e.g. printers and aural devices, downloadable fonts,
element positioning and tables.

CSS SYNTAX – SELECTORS

CSS SYNTAX – SELECTORS
• A CSS comprises of style rules that are interpreted by the browser and then applied to the
corresponding elements in your document. A style rule is made of three parts:
• SELECTOR:
• A selector is an HTML tag at which style will be applied. This could be any tag like <h1> or
<table> etc.
• PROPERTY:
• A property is a type of attribute of HTML tag. Put simply, all the HTML attributes are
converted into CSS properties. They could be color or border etc.
• VALUE:
• Values are assigned to properties. For example color property can have value either red or
#F1F1F1 etc.

CSS SYNTAX – SELECTORS (Syntax)
• You can put CSS Style Rule Syntax as follows:
selector { property: value }
• Example:
• You can define a table border as follows:
table{ border :1px solid #C00; }

CSS SYNTAX – SELECTORS (Type Selectors)
• This is the same selector we have seen above. Again one more example to
give a color to all level 1 headings :
h1 {
color: #36CFFF;
}

CSS SYNTAX – SELECTORS (Universal Selectors)
• Rather than selecting elements of a specific type, the universal selector quite simply matches
the name of any element type
* {
color: #36CFFF;
}
• This rule renders the content of every element in our document in black.

CSS SYNTAX – SELECTORS (Descendant Selectors)
• Suppose you want to apply a style rule to a particular element only when it lies inside a
particular element. As given in the following example, style rule will apply to <em> element
only when it lies inside <ul> tag.
ul em{
color: #36CFFF;
}

CSS SYNTAX – SELECTORS (Class Selectors)
• You can define style rules based on the class attribute of the elements. All the
elements having that class will be formatted according to the defined rule.
.black {
color: #36CFFF;
}
H1.black {
color: green;
}

CSS SYNTAX – SELECTORS (Class Selectors)
• This rule renders the content in black for only <h1> elements with class attribute set to black.
• You can apply more than one class selectors to given element.
<p class= "center bold“ >This para will be styled by the classes center and bold. </p>

CSS SYNTAX – SELECTORS (ID Selectors)
• This rule renders the content in black for every element with id attribute set to black in
our document. You can make it a bit more particular.
#black {color: #36CFFF;}
h1#black {color: #36CFFF;}
• The true power of id selectors is when they are used as the ground work for
descendant selectors
#black h2 {color: #36CFFF;}
• In this example all level 2 headings will be displayed in black color only when those
headings will lie with in tags having id attribute set to black.

CSS SYNTAX – SELECTORS (Child Selectors)
• You have seen descendant selectors. There is one more type of selectors which is very similar
to descendants but have different functionality
Body> p {color: #36CFFF; }
• This rule will render all the paragraphs in black if they are direct child of <body> element.
Other paragraphs put inside other elements like <div> or <td> etc. would not have any effect
of this rule.

CSS SYNTAX – SELECTORS (Multiple Style Rules)
• You may need to define multiple style rules for a single element. You can define
these rules to combine multiple properties and corresponding values into a single
block as defined
h1{
color: #36CFFF;
font-weight: normal;
letter-spacing: .4em;
text-transform: #36cff;
}

CSS SYNTAX – SELECTORS (Grouping Selectors)
• You can apply a style to many selectors if you like. Just separate the selectors with a comma.
h1 , h2 , h3 {
color: #36CFFF;
}
• You can combine various class selectors together as shown below:
#content, #footer , #supplement {
position: absolute;
left: 510px;
width: 200px ;
}

CSS INCLUSION – ASSOIATING STYLES

CSS INCLUSION – ASSOIATING STYLES (embedded css)
• There are four ways to associate styles with your HTML document. Most
commonly used methods are inline CSS and External CSS.
• You can put your CSS rules into an HTML document using the <style> element.
This tag is placed inside <head>...</head> tags. Rules defined using this
syntax will be applied to all the elements available in the document
<head>
<style type="text/css" media="all"> h1{ color: #36C; } </style>
</head>

CSS INCLUSION – ASSOIATING STYLES (Inline CSS )
• You can use style attribute of any HTML element to define style rules. These
rules will be applied to that element only. Here is the generic syntax:
<h1 style ="color:#36C;"> This is inline CSS </h1>

CSS INCLUSION – ASSOIATING STYLES ( External CSS )
• The <link> element can be used to include an external stylesheet file in your HTML
document.
• An external style sheet is a separate text file with .css extension. You define all the Style rules
within this text file and then you can include this file in any HTML document using <link>
element.
• Consider a simple style sheet file with a name mystyle.css having the following rules:
h1 , h2 , h3 {
color: #36CFFF;
}
• Now you can include this file mystyle.css in any HTML document as follows:
• <head> <link type="text/css" href="mystyle.css" media="all" /> </head>

CSS INCLUSION – ASSOIATING STYLES (Imported CSS )
• Imported CSS - @import Rule:
• @import is used to import an external stylesheet in a manner similar to the <link> element.
Here is the generic syntax of @import rule.
<head> <@import "URL"; </head>
• Here URL is the URL of the style sheet file having style rules. You can use another syntax as
well:
<head> <@import url("URL"); </head>
• EXAMPLE:
• Following is the example showing you how to import a style sheet file into HTML document:
<head> @import "mystyle.css"; </head>

CSS INCLUSION – ASSOIATING STYLES (CSS Rules Overriding)
• We have discussed four ways to include style sheet rules in a an HTML
document. Here is the rule to override any Style Sheet Rule.
• Any inline style sheet takes highest priority. So it will override any rule defined
in <style>...</style> tags or rules defined in any external style sheet file.
• Any rule defined in <style>...</style> tags will override rules defined in any
external style sheet file.
• Any rule defined in external style sheet file takes lowest priority and rules
defined in this file will be applied only when above two rules are not
applicable.

CSS INCLUSION – ASSOIATING STYLES (CSS Comments)
• Many times you may need to put additional comments in your style sheet
blocks. So it is very easy to comment any part in style sheet. You simple put
your comments inside /*.....this is a comment in style sheet.....*/.
• You can use /* ....*/ to comment multi-line blocks in similar way you do in C
and C++ programming languages.

CSS – LINKS

CSS – LINKS
• We will revisit same properties when we will discuss Pseudo-Classes
of CSS
• The :link Signifies unvisited hyperlinks.
• The :visited Signifies visited hyperlinks.
• The :hover Signifies an element that currently has the user's mouse pointer
hovering over it.
• The :active Signifies an element on which the user is currently clicking.

CSS – LINKS
• Remember a:hover MUST come after a:link and a:visited in the CSS definition
in order to be effective. Also, a:active MUST come after a:hover in the CSS
definition as follows.
<style type="text/css">
a:link {color: #000000}
a:visited {color: #006600}
a:hover {color: #FFCC00}
a:active {color: #FF00CC}
</style>

Css presentation lecture 1

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