This document provides an introduction to CSS (Cascading Style Sheets) through a series of lessons:
- Lesson 1 defines CSS and its history, purpose of separating formatting from content, and examples of how CSS changes page appearance without altering HTML.
- Lesson 2 explains CSS syntax including selectors, declarations, properties/values, and declaration blocks. Students create their first CSS page.
- Lesson 3 covers CSS class and ID selectors. Students create pages using class and ID selectors.
- Lesson 4 describes three methods to apply CSS - inline, internal, and external style sheets.
The document includes assignments for students to practice CSS concepts by modifying provided code examples.
2. IntroductionIntroduction
To CSSTo CSS
by: Alexandra Vlachakisby: Alexandra Vlachakis
Sandy Creek High School, Fayette County SchoolsSandy Creek High School, Fayette County Schools
Content and Resources Used With Permission:Content and Resources Used With Permission:
Interact With Web Standards. Copyright 2010. Erin Anderson et. Al.Interact With Web Standards. Copyright 2010. Erin Anderson et. Al.
W3 Schools. www.w3schools.com. 12-25-11.W3 Schools. www.w3schools.com. 12-25-11.
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3. HTML ReviewHTML Review
► What is HTML used for?
► Give some examples of formatting tags in
HTML?
► HTML is the most widely used language on the
Web
► In today’s lesson we will be discussing the
second most widely used language on the web
► Does anyone know the name of the second most
widely used language?
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4. Lesson 1: History of CSSLesson 1: History of CSS
► CSS was proposed in 1994 as a web styling
language. To helps solve some of the
problems HTML 4.
► There were other styling languages
proposed at this time, such as Style Sheets
for HTML and JSSS but CSS won.
► CSS2 became the recommendation in 1998
by W3C
► CSS3 was started in 1998 but it has never
been completed. Some parts are still being
developed and some components work on
some browsers.
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5. Lesson 1: What is CSS?Lesson 1: What is CSS?
• CSSCSS stands forstands for CCascadingascading SStyletyle SSheetsheets
• Styles - defineStyles - define how to displayhow to display HTML elementsHTML elements
• Styles are normally stored inStyles are normally stored in Style SheetsStyle Sheets
Definition:Definition:
Cascading Style Sheets (CSS) – is a rule based
language that applies styling to your HTML elements.
You write CSS rules in elements, and modify properties
of those elements such as color, background color,
width, border thickness, font size, etc.
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6. Lesson 1: Examples ofLesson 1: Examples of
CSSCSS
► Example 1: http://www.csszengarden.com/Example 1: http://www.csszengarden.com/
► Example 2: http://w3schools.com/css/demo_default.htmExample 2: http://w3schools.com/css/demo_default.htm
► If you notice each time we click on a different CSS style sheet on theIf you notice each time we click on a different CSS style sheet on the
two pages above the look and feel of each page changes dramaticallytwo pages above the look and feel of each page changes dramatically
but the content stays the same.but the content stays the same.
► HTML did not offer us this option.HTML did not offer us this option.
► HTML was never intended to contain tags for formatting a document.HTML was never intended to contain tags for formatting a document.
► HTML was intended to define the content of a document, like:HTML was intended to define the content of a document, like:
► <h1>This is a heading</h1><h1>This is a heading</h1>
► <p>This is a paragraph.</p><p>This is a paragraph.</p>
► When tags like <font>, and color attributes were added to the HTMLWhen tags like <font>, and color attributes were added to the HTML
3.2 specification, it started a nightmare for web developers.3.2 specification, it started a nightmare for web developers.
Development of large web sites, where fonts and color informationDevelopment of large web sites, where fonts and color information
were added to every single page, became a long and expensivewere added to every single page, became a long and expensive
process.process.
► To solve this problem, the World Wide Web Consortium (W3C) createdTo solve this problem, the World Wide Web Consortium (W3C) created
CSS.CSS.
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7. HTML Formatting ReviewHTML Formatting Review
► What are the starting tags in HTML?What are the starting tags in HTML?
► What are the ending tags in HTML?What are the ending tags in HTML?
► How do you save in a Notepad document so itHow do you save in a Notepad document so it
becomes a web page?becomes a web page?
► What is the tag for creating paragraphs inWhat is the tag for creating paragraphs in
HTML?HTML?
► What is the tag for creating heading tags inWhat is the tag for creating heading tags in
HTML?HTML?
► What are the tags we use to format font: family,What are the tags we use to format font: family,
color, size, alignment in HTML?color, size, alignment in HTML?Css Founder.com
8. Lesson 2:Lesson 2: Syntax oF CSSSyntax oF CSS
The CSS syntax is made up of 5 parts:The CSS syntax is made up of 5 parts:
selectorselector
property/valueproperty/value
declarationdeclaration
declaration blockdeclaration block
curly bracescurly braces
We will explore each part in the next slides.We will explore each part in the next slides.
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9. SelectorSelector
Definition: identifies the HTML elements that theDefinition: identifies the HTML elements that the
rule will be applied to, identified by the actualrule will be applied to, identified by the actual
element name, e.g. <body>, or by other meanselement name, e.g. <body>, or by other means
such assuch as classclass attribute values.attribute values.
Example:Example:
*The selector is normally the HTML element you want to style
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10. Property & ValueProperty & Value
Definition:Definition: The property is the style attribute you
want to change. Each property has a value.
*Properties are separated from their respective values by*Properties are separated from their respective values by
colonscolons ::
*Pairs are separated from each other byPairs are separated from each other by semicolonssemicolons ;;Css Founder.com
11. DeclarationDeclaration
Definition: Each CSS line that includes propertyDefinition: Each CSS line that includes property
and valueand value
*Each declaration consists of a property and a value.
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13. Curly BracesCurly Braces
Definition: the curly braces contain theDefinition: the curly braces contain the
properties of the element you want toproperties of the element you want to
manipulate, and the values that you want tomanipulate, and the values that you want to
change them to. The curly braces plus theirchange them to. The curly braces plus their
content is called a declaration block.content is called a declaration block.
Example:Example:
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14. Lesson 2 Assignment:Lesson 2 Assignment:
Let’s Create Our First CSS PageLet’s Create Our First CSS Page
► Open NotepadOpen Notepad
► Type the following CodeType the following Code
<html><html>
<head><head>
<style type="text/css"><style type="text/css">
p {color:red; text-align:center;}p {color:red; text-align:center;}
</style></style>
</head></head>
<body><body>
<p>Hello World!</p><p>Hello World!</p>
<p>This paragraph is styled with CSS.</p><p>This paragraph is styled with CSS.</p>
</body></body>
</html></html>
► Save Your File as css-myfirstpage.html into a new folder called CSSSave Your File as css-myfirstpage.html into a new folder called CSS
►Instructor Note: You canInstructor Note: You can
demonstrate how to do this bydemonstrate how to do this by
using the example given on theusing the example given on the
W3schools site. Also as you areW3schools site. Also as you are
creating this file point out tocreating this file point out to
students where they will find thestudents where they will find the
different syntax found in CSS.different syntax found in CSS.
►After creating the file haveAfter creating the file have
students manipulate the color andstudents manipulate the color and
alignment values.alignment values.
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15. Lesson 3:Lesson 3: Class and idClass and id
SelectorsSelectors In addition to setting a style for a HTML element, CSS allowsIn addition to setting a style for a HTML element, CSS allows
you to specify your own selectors called "id" and "class".you to specify your own selectors called "id" and "class".
idid -- The id selector is used to specify a style for a single, uniqueThe id selector is used to specify a style for a single, unique
element.element.
The id selector uses the id attribute of the HTML element,The id selector uses the id attribute of the HTML element,
and is defined with a "#".and is defined with a "#".
The style rule below will be applied to the element withThe style rule below will be applied to the element with
id="para1":id="para1":
#para1 {text-align:center;color:red;}#para1 {text-align:center;color:red;}
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16. Lesson 3:Lesson 3: Class and idClass and id
SelectorsSelectorsClassClass -- The class selector is used to specify a style for a groupThe class selector is used to specify a style for a group
of elements. Unlike the id selector, the class selector is mostof elements. Unlike the id selector, the class selector is most
often used on several elements.often used on several elements.
This allows you to set a particular style for any HTMLThis allows you to set a particular style for any HTML
elements with the same class.elements with the same class.
The class selector uses the HTML class attribute, and isThe class selector uses the HTML class attribute, and is
defined with a "."defined with a "."
In the example below, all HTML elements with class="center"In the example below, all HTML elements with class="center"
will be center-aligned:will be center-aligned:
.center {text-align:center;}.center {text-align:center;}
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17. Lesson 3:Lesson 3: Class and idClass and id
SelectorsSelectors
In the image below what is the h1 selectorIn the image below what is the h1 selector
an ID or a Class?an ID or a Class?
#
.
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18. Lesson 3 Assignment:Lesson 3 Assignment:
Let’s Create A CSS Page that uses “id”Let’s Create A CSS Page that uses “id”
► Open NotepadOpen Notepad
► Type the following CodeType the following Code
<html>
<head>
<style type="text/css">
#para1
{
text-align:center;
color:red;
}
</style>
</head>
<body>
<p id="para1">Hello World!</p>
<p>This paragraph is not affected by the style.</p>
</body>
</html>
► Save Your File as css-id.html into a your folder called CSS.Save Your File as css-id.html into a your folder called CSS.
►Instructor Note: You canInstructor Note: You can
demonstrate how to do this bydemonstrate how to do this by
using the example given on theusing the example given on the
W3schools site. Also as you areW3schools site. Also as you are
creating this file point out tocreating this file point out to
students where they will find thestudents where they will find the
different syntax found in CSSdifferent syntax found in CSS
►After creating the file haveAfter creating the file have
students manipulate the name ofstudents manipulate the name of
the “id”the “id”
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19. Lesson 3 Assignment:Lesson 3 Assignment:
Let’s Create A CSS Page that uses “class”Let’s Create A CSS Page that uses “class”
► Open NotepadOpen Notepad
► Type the following CodeType the following Code
<html>
<head>
<style type="text/css">
.center
{
text-align:center;
}
</style>
</head>
<body>
<h1 class="center">Center-aligned heading</h1>
<p class="center">Center-aligned paragraph.</p>
</body>
</html>
► Save Your File as css-class.html into a your folder called CSS.Save Your File as css-class.html into a your folder called CSS.
►Instructor Note: You canInstructor Note: You can
demonstrate how to do this bydemonstrate how to do this by
using the example given on theusing the example given on the
W3schools site. Also as you areW3schools site. Also as you are
creating this file point out tocreating this file point out to
students where they will find thestudents where they will find the
different syntax found in CSSdifferent syntax found in CSS
►After creating the file haveAfter creating the file have
students manipulate the name ofstudents manipulate the name of
the “class”the “class”
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20. Lesson 3 CommentsLesson 3 Comments
► Comments are used to explain your code, and may help you when you editComments are used to explain your code, and may help you when you edit
the source code at a later date. Comments are ignored by browsers.the source code at a later date. Comments are ignored by browsers.
► You add comments by enclosing them inYou add comments by enclosing them in
/* and *//* and */
► Comments can span several lines, and the browser will ignore these lines.Comments can span several lines, and the browser will ignore these lines.
► Example:Example:
► /* This is a basic comment it will not appear on the page*/ /* This is a basic comment it will not appear on the page*/
/* starts the comment/* starts the comment
*/ is the end of the comment*/ is the end of the comment
/*This is a comment*//*This is a comment*/
p{ text-align:center; color:black; font-family:arial;}p{ text-align:center; color:black; font-family:arial;}
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21. Lesson 3 Assignment:Lesson 3 Assignment:
Let’s Add A CommentLet’s Add A Comment
► Open Your CSS-ID example in NotepadOpen Your CSS-ID example in Notepad
► Type the following Code right above the style you had written previously.Type the following Code right above the style you had written previously.
<html>
<head>
/*This is an example of how to use ID in a CSS web page*//*This is an example of how to use ID in a CSS web page*/
<style type="text/css">
#para1
{
text-align:center;
color:red;
}
</style>
</head>
<body>
<p id="para1">Hello World!</p>
<p>This paragraph is not affected by the style.</p>
</body>
</html>
► Save Your File as css-comment.html into a your folder called CSS.Save Your File as css-comment.html into a your folder called CSS.
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22. Lesson 4:Lesson 4: How CSS is Applied to A WebHow CSS is Applied to A Web
PagePage
►CSS is applied to a web page using threeCSS is applied to a web page using three
different methods:different methods:
Inline styleInline style
Internal style sheetInternal style sheet
External style sheetExternal style sheet
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23. ►Inline CSSInline CSS
►Applies styles directly to the elements byApplies styles directly to the elements by
adding declarations into the styleadding declarations into the style
►For Example:For Example:
<p style=“color: red;”> This is a simple<p style=“color: red;”> This is a simple
paragraph and the inline style makes itparagraph and the inline style makes it
red.</p>red.</p>
Lesson 4:Lesson 4: How CSS is Applied to A WebHow CSS is Applied to A Web
PagePage
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24. ► Internal Style SheetInternal Style Sheet
► Applies styles to HTML by placing the CSS rules inside the tagApplies styles to HTML by placing the CSS rules inside the tag
<style> inside the document tag <head>.<style> inside the document tag <head>.
► For Example:For Example:
<head><head>
<title>my page</title><title>my page</title>
<style type=“text/css”><style type=“text/css”>
p{color:red}</style>p{color:red}</style>
</head></head>
<body><body>
<p>this is a simple paragraph<p>this is a simple paragraph
</p></p>
</body></body>
Lesson 4:Lesson 4: How CSS is Applied to A WebHow CSS is Applied to A Web
PagePage
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25. ► External CSSExternal CSS
► Applies styles as a separate file with a .css extension. The file isApplies styles as a separate file with a .css extension. The file is
then referenced from inside the <head> element by a link to thethen referenced from inside the <head> element by a link to the
file.file.
► For Example:For Example:
<head><head>
<title>my external style sheet page</title><title>my external style sheet page</title>
<link rel=“style sheet” type=“text/css” href=“my-external-<link rel=“style sheet” type=“text/css” href=“my-external-
stylesheet.css”>stylesheet.css”>
<body><body>
<p>this is a simple paragraph</p><p>this is a simple paragraph</p>
</body></body>
► You can create an external style sheet in your text editor.You can create an external style sheet in your text editor.
Lesson 4:Lesson 4: How CSS is Applied to A WebHow CSS is Applied to A Web
PagePage
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26. ► What style sheet is best?What style sheet is best?
► Web developers rarely use inline CSS. Since they preferWeb developers rarely use inline CSS. Since they prefer
to not mix content with presentation. And it is notto not mix content with presentation. And it is not
efficient since you have to declare the style individuallyefficient since you have to declare the style individually
for every component.for every component.
► Internal and External style sheets are more popularInternal and External style sheets are more popular
because you can style multiple elements with one rule.because you can style multiple elements with one rule.
► External style sheets are best because they allow you toExternal style sheets are best because they allow you to
save all the style information on a separate file from thesave all the style information on a separate file from the
content. You can then modify a style for a site and it willcontent. You can then modify a style for a site and it will
update all of the pages in a site.update all of the pages in a site.
Lesson 4:Lesson 4: How CSS is Applied to A WebHow CSS is Applied to A Web
PagePage
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27. ►CSS ColorsCSS Colors
►In the previous lesson you have seen a fewIn the previous lesson you have seen a few
CSS styles that included color like: <pCSS styles that included color like: <p
style=“color: red;”>style=“color: red;”>
►There are a few ways that you can setThere are a few ways that you can set
colors in CSS:colors in CSS:
Keywords, Hex values, RGB, HSL(a)Keywords, Hex values, RGB, HSL(a)
Lesson 5:Lesson 5: Colors and Formatting in CSSColors and Formatting in CSS
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28. ► CSS Colors: KeywordsCSS Colors: Keywords
► Using the keywords like: red, fuchsia, yellow,Using the keywords like: red, fuchsia, yellow,
blue, green you can specify what color you wouldblue, green you can specify what color you would
like the CSS rule to display.like the CSS rule to display.
► For example:For example:
► p{color:red}p{color:red}
► h2{color:yellow}h2{color:yellow}
► There are 17 of these keyword colors you canThere are 17 of these keyword colors you can
use in CSS.use in CSS.
Lesson 5:Lesson 5: Colors and Formatting in CSSColors and Formatting in CSS
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29. Keyword ColorKeyword Color HexHex
aqua #00ffff
black #000000
blue #0000ff
fuchsia #ff00ff
gray #808080
green #008000
lime #00ff00
maroon #800000
navy #000080
olive #808000
orange (added in CSS 2.1) #ffa500
purple #800080
red #ff0000
silver #c0c0c0
teal #008080
white #ffffff
yellow #ffff00
Lesson 5:Lesson 5: Colors and Formatting in CSSColors and Formatting in CSS
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30. ► Computers are capable of displaying a lot moreComputers are capable of displaying a lot more
than 17 colors.than 17 colors.
► In fact they can display approximately 16.7In fact they can display approximately 16.7
million colors!million colors!
► Hex Values (hex is short for hexadecimal) areHex Values (hex is short for hexadecimal) are
the most common way of specifying colors forthe most common way of specifying colors for
web pages. (see hex# in the previous chart)web pages. (see hex# in the previous chart)
► For example:For example:
p{color: #000000;}p{color: #000000;}
/*This is equivalent to the keyword black*//*This is equivalent to the keyword black*/
Lesson 5:Lesson 5: Colors and Formatting in CSSColors and Formatting in CSS
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31. ►Hex numbersHex numbers - has 16 possible values- has 16 possible values
►0 to 9 then A to F. Which gives you 160 to 9 then A to F. Which gives you 16
values.values.
►RGB (Red Green Blue) has the possibilityRGB (Red Green Blue) has the possibility
of 256 colors for each (16x16)of 256 colors for each (16x16)
►(R)256 x (G)256 x (B)256 = 16,777,216 or(R)256 x (G)256 x (B)256 = 16,777,216 or
16.7 million color values16.7 million color values
►CSS example: h1{color: #000000;}CSS example: h1{color: #000000;}
Lesson 5:Lesson 5: Colors and Formatting in CSSColors and Formatting in CSS
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32. ► RGB (a)RGB (a) can also help specify colors in CSScan also help specify colors in CSS
RGB stands for Red Green BlueRGB stands for Red Green Blue
► You can specify RGB in either whole numbers orYou can specify RGB in either whole numbers or
percentagespercentages
► CSS example: h1{color: rgb(0,0,0) }CSS example: h1{color: rgb(0,0,0) }
/*this color is equivalent to #000000 or black *//*this color is equivalent to #000000 or black */
► You use numbers from 0 to 255 which covers theYou use numbers from 0 to 255 which covers the
256 color range.256 color range.
► More examples can be found at:More examples can be found at:
http://www.w3schools.com/css/css_colors.asphttp://www.w3schools.com/css/css_colors.asp
Lesson 5:Lesson 5: Colors and Formatting in CSSColors and Formatting in CSS
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33. ► RGB (a)RGB (a) can also help specify colors in CSS RGBcan also help specify colors in CSS RGB
stands for Red Green Blue. The “a” stands for alpha butstands for Red Green Blue. The “a” stands for alpha but
we will learn about that in another lesson.we will learn about that in another lesson.
► You can specify RGB in either whole numbers orYou can specify RGB in either whole numbers or
percentagespercentages
► CSS example: h1{color: rgb(0,0,0) }CSS example: h1{color: rgb(0,0,0) }
/*this color is equivalent to #000000 or black *//*this color is equivalent to #000000 or black */
► You use numbers from 0 to 255 which covers the 256You use numbers from 0 to 255 which covers the 256
color range.color range.
► More examples can be found at:More examples can be found at:
http://www.w3schools.com/css/css_colors.asphttp://www.w3schools.com/css/css_colors.asp
Lesson 5:Lesson 5: Colors and Formatting in CSSColors and Formatting in CSS
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34. ► HSL (a)HSL (a) - Hue Saturation Lightness- Hue Saturation Lightness
► Similar to RGB but based on saturation andSimilar to RGB but based on saturation and
lightness of a colorlightness of a color
► The “a” stands for alpha but we will learn aboutThe “a” stands for alpha but we will learn about
that in another lesson.that in another lesson.
► CSS example: h1{color: hsl(0,100%,40%) }CSS example: h1{color: hsl(0,100%,40%) }
► HSL accepts a number between 0 to 360 in valueHSL accepts a number between 0 to 360 in value
► HSL also accepts percentage between 0-100%HSL also accepts percentage between 0-100%
Lesson 5:Lesson 5: Colors and Formatting in CSSColors and Formatting in CSS
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35. Lesson 5 Assignment:Lesson 5 Assignment:
CSS Using ColorCSS Using Color
► Open Your CSS-ID example in NotepadOpen Your CSS-ID example in Notepad
► Type the following Code right above the style you had written previously.Type the following Code right above the style you had written previously.
<html>
<body>
<p style="background-color:#FFF111">
Color set by using hex value
</p>
<p style="background-color:rgb(0,255,0);">
Color set by using rgb value
</p>
<p style="background-color:red">
Color set by using color name
</p>
</body>
</html>
► Save Your File as css-color.html into your folder called CSSSave Your File as css-color.html into your folder called CSS
►Instructor Note: You canInstructor Note: You can
demonstrate how to do this bydemonstrate how to do this by
using the example given on theusing the example given on the
W3schools site. Also as you areW3schools site. Also as you are
creating this file point out tocreating this file point out to
students the different syntax foundstudents the different syntax found
in CSS.in CSS.
►After creating the file haveAfter creating the file have
students manipulate the colorstudents manipulate the color
values to discover other colorvalues to discover other color
combinations.combinations.
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