What is CSS
CSS stands for Cascading Style Sheets. It is a style sheet language which is
used to describe the look and formatting of a document written in markup
language. It provides an additional feature to HTML. It is generally used with
HTML to change the style of web pages and user interfaces. It can also be
used with any kind of XML documents including plain XML, SVG and XUL.
CSS is used along with HTML and JavaScript in most websites to create user
interfaces for web applications and user interfaces for many mobile
applications.
What does CSS do
o You can add new looks to your old HTML documents.
o You can completely change the look of your website with only a few
changes in CSS code.
Why use CSS
These are the three major benefits of CSS:
1) Solves a big problem
Before CSS, tags like font, color, background style, element alignments,
border and size had to be repeated on every web page. This was a very long
process. For example: If you are developing a large website where fonts and
color information are added on every single page, it will be become a long
and expensive process. CSS was created to solve this problem. It was a W3C
recommendation.
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2) Saves a lot of time
CSS style definitions are saved in external CSS files so it is possible to
change the entire website by changing just one file.
, 3) Provide more attributes
CSS provides more detailed attributes than plain HTML to define the look and
feel of the website.
CSS Syntax
A CSS rule set contains a selector and a declaration block.
Selector: Selector indicates the HTML element you want to style. It could be
any tag like <h1>, <title> etc.
Declaration Block: The declaration block can contain one or more
declarations separated by a semicolon. For the above example, there are
two declarations:
1. color: yellow;
2. font-size: 11 px;
Each declaration contains a property name and value, separated by a colon.
Property: A Property is a type of attribute of HTML element. It could be
color, border etc.
Value: Values are assigned to CSS properties. In the above example, value
"yellow" is assigned to color property.
1. Selector{Property1: value1; Property2: value2; ..........;}
,CSS Selector
CSS selectors are used to select the content you want to style. Selectors
are the part of CSS rule set. CSS selectors select HTML elements according to
its id, class, type, attribute etc.
There are several different types of selectors in CSS.
1) CSS Id Selector
The id selector selects the id attribute of an HTML element to select a
specific element. An id is always unique within the page so it is chosen to
select a single, unique element.
It is written with the hash character (#), followed by the id of the element.
<!DOCTYPE html>
<html>
<head>
<style>
#para1 {
text-align: center;
color: blue;
}
</style>
</head>
<body>
<p id="para1">Hello Javatpoint.com</p>
<p>This paragraph will not be affected.</p>
</body>
</html>
, Output:
Hello Javatpoint.com
This paragraph will not be affected.
3) CSS Class Selector
The class selector selects HTML elements with a specific class attribute. It is
used with a period character . (full stop symbol) followed by the class name.
<!DOCTYPE html>
<html>
<head>
<style>
.center {
text-align: center;
color: blue;
}
</style>
</head>
<body>
<h1 class="center">This heading is blue and center-aligned.</h1>
<p class="center">This paragraph is blue and center-aligned.</p>
</body>
</html>
Output:
This heading is blue and center-aligned.
CSS stands for Cascading Style Sheets. It is a style sheet language which is
used to describe the look and formatting of a document written in markup
language. It provides an additional feature to HTML. It is generally used with
HTML to change the style of web pages and user interfaces. It can also be
used with any kind of XML documents including plain XML, SVG and XUL.
CSS is used along with HTML and JavaScript in most websites to create user
interfaces for web applications and user interfaces for many mobile
applications.
What does CSS do
o You can add new looks to your old HTML documents.
o You can completely change the look of your website with only a few
changes in CSS code.
Why use CSS
These are the three major benefits of CSS:
1) Solves a big problem
Before CSS, tags like font, color, background style, element alignments,
border and size had to be repeated on every web page. This was a very long
process. For example: If you are developing a large website where fonts and
color information are added on every single page, it will be become a long
and expensive process. CSS was created to solve this problem. It was a W3C
recommendation.
Backward Skip 10sPlay VideoForward Skip 10s
2) Saves a lot of time
CSS style definitions are saved in external CSS files so it is possible to
change the entire website by changing just one file.
, 3) Provide more attributes
CSS provides more detailed attributes than plain HTML to define the look and
feel of the website.
CSS Syntax
A CSS rule set contains a selector and a declaration block.
Selector: Selector indicates the HTML element you want to style. It could be
any tag like <h1>, <title> etc.
Declaration Block: The declaration block can contain one or more
declarations separated by a semicolon. For the above example, there are
two declarations:
1. color: yellow;
2. font-size: 11 px;
Each declaration contains a property name and value, separated by a colon.
Property: A Property is a type of attribute of HTML element. It could be
color, border etc.
Value: Values are assigned to CSS properties. In the above example, value
"yellow" is assigned to color property.
1. Selector{Property1: value1; Property2: value2; ..........;}
,CSS Selector
CSS selectors are used to select the content you want to style. Selectors
are the part of CSS rule set. CSS selectors select HTML elements according to
its id, class, type, attribute etc.
There are several different types of selectors in CSS.
1) CSS Id Selector
The id selector selects the id attribute of an HTML element to select a
specific element. An id is always unique within the page so it is chosen to
select a single, unique element.
It is written with the hash character (#), followed by the id of the element.
<!DOCTYPE html>
<html>
<head>
<style>
#para1 {
text-align: center;
color: blue;
}
</style>
</head>
<body>
<p id="para1">Hello Javatpoint.com</p>
<p>This paragraph will not be affected.</p>
</body>
</html>
, Output:
Hello Javatpoint.com
This paragraph will not be affected.
3) CSS Class Selector
The class selector selects HTML elements with a specific class attribute. It is
used with a period character . (full stop symbol) followed by the class name.
<!DOCTYPE html>
<html>
<head>
<style>
.center {
text-align: center;
color: blue;
}
</style>
</head>
<body>
<h1 class="center">This heading is blue and center-aligned.</h1>
<p class="center">This paragraph is blue and center-aligned.</p>
</body>
</html>
Output:
This heading is blue and center-aligned.
