Tutorial CSS programing for web master

What You Should Already Know

Before you continue you should have a basic understanding of the following:

• HTML / XHTML

If you want to study these subjects first, find the tutorials on our Home page.

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What is CSS?

• CSS stands for Cascading Style Sheets
• Styles define how to display HTML elements
• Styles were added to HTML 4.0 to solve a problem
• External Style Sheets can save a lot of work
• External Style Sheets are stored in CSS files

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CSS Demo

An HTML document can be displayed with different styles: See how it works

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Styles Solved a Big Problem

HTML was never intended to contain tags for formatting a document.

HTML was intended to define the content of a document, like:

<h1>This is a heading</h1>

<p>This is a paragraph.</p>

When tags like <font>, and color attributes were added to the HTML 3.2 specification, it started a nightmare for web developers. Development of large web sites, where fonts and color information were added to every single page, became a long and expensive process.

To solve this problem, the World Wide Web Consortium (W3C) created CSS.

In HTML 4.0, all formatting could be removed from the HTML document, and stored in a separate CSS file.

All browsers support CSS today.

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CSS Saves a Lot of Work!

CSS defines HOW HTML elements are to be displayed.

Styles are normally saved in external .css files. External style sheets enable you to change the appearance and layout of all the pages in a Web site, just by editing one single file!

Examples

• Look at Example 1
• Look at Example 2

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CSS Syntax

A CSS rule has two main parts: a selector, and one or more declarations:

The selector is normally the HTML element you want to style.

Each declaration consists of a property and a value.

The property is the style attribute you want to change. Each property has a value.

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CSS Example

A CSS declaration always ends with a semicolon, and declaration groups are surrounded by curly brackets:

p {color:red;text-align:center;}

To make the CSS more readable, you can put one declaration on each line, like this:

Example

p
{
color:red;
text-align:center;
}

Try it yourself »

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CSS Comments

Comments 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.

A CSS comment begins with "/*", and ends with "*/", like this:

/*This is a comment*/
p
{
text-align:center;
/*This is another comment*/
color:black;
font-family:arial;
}

The id and class Selectors

In addition to setting a style for a HTML element, CSS allows you to specify your own selectors called "id" and "class".

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The id Selector

The id selector is used to specify a style for a single, unique element.

The id selector uses the id attribute of the HTML element, and is defined with a "#".

The style rule below will be applied to the element with id="para1":

Example

#para1
{
text-align:center;
color:red;
}

Try it yourself »

 Do NOT start an ID name with a number! It will not work in Mozilla/Firefox.

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The class Selector

The class selector is used to specify a style for a group of elements. Unlike the id selector, the class selector is most often used on several elements.

This allows you to set a particular style for many HTML elements with the same class.

The class selector uses the HTML class attribute, and is defined with a "."

In the example below, all HTML elements with class="center" will be center-aligned:

Example

.center {text-align:center;}

Try it yourself »

You can also specify that only specific HTML elements should be affected by a class.

In the example below, all p elements with class="center" will be center-aligned:

Example

p.center {text-align:center;}

Try it yourself »

 Do NOT start a class name with a number! This is only supported in Internet Explorer.

When a browser reads a style sheet, it will format the document according to it.

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Three Ways to Insert CSS

There are three ways of inserting a style sheet:

• External style sheet
• Internal style sheet
• Inline style

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External Style Sheet

An external style sheet is ideal when the style is applied to many pages. With an external style sheet, you can change the look of an entire Web site by changing one file. Each page must link to the style sheet using the <link> tag. The <link> tag goes inside the head section:

<head>
<link rel="stylesheet" type="text/css" href="mystyle.css">
</head>

An external style sheet can be written in any text editor. The file should not contain any html tags. Your style sheet should be saved with a .css extension. An example of a style sheet file is shown below:

hr {color:sienna;}
p {margin-left:20px;}
body {background-image:url("images/back40.gif");}

 Do not add a space between the property value and the unit (such as margin-left:20 px). The correct way is: margin-left:20px

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Internal Style Sheet

An internal style sheet should be used when a single document has a unique style. You define internal styles in the head section of an HTML page, by using the <style> tag, like this:

<head>
<style>
hr {color:sienna;}
p {margin-left:20px;}
body {background-image:url("images/back40.gif");}
</style>
</head>

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Inline Styles

An inline style loses many of the advantages of style sheets by mixing content with presentation. Use this method sparingly!

To use inline styles you use the style attribute in the relevant tag. The style attribute can contain any CSS property. The example shows how to change the color and the left margin of a paragraph:

<p style="color:sienna;margin-left:20px">This is a paragraph.</p>

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Multiple Style Sheets

If some properties have been set for the same selector in different style sheets, the values will be inherited from the more specific style sheet. 

For example, an external style sheet has these properties for the h3 selector:

h3
{
color:red;
text-align:left;
font-size:8pt;
}

And an internal style sheet has these properties for the h3 selector:

h3
{
text-align:right;
font-size:20pt;
}

If the page with the internal style sheet also links to the external style sheet the properties for h3 will be:

color:red;
text-align:right;
font-size:20pt;

The color is inherited from the external style sheet and the text-alignment and the font-size is replaced by the internal style sheet.

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Multiple Styles Will Cascade into One

Styles can be specified:

• inside an HTML element
• inside the head section of an HTML page
• in an external CSS file

Tip: Even multiple external style sheets can be referenced inside a single HTML document.

Cascading order

What style will be used when there is more than one style specified for an HTML element?

Generally speaking we can say that all the styles will "cascade" into a new "virtual" style sheet by the following rules, where number four has the highest priority:

1.    Browser default

2.    External style sheet

3.    Internal style sheet (in the head section)

4.    Inline style (inside an HTML element)

So, an inline style (inside an HTML element) has the highest priority, which means that it will override a style defined inside the <head> tag, or in an external style sheet, or in a browser (a default value).

 Note: If the link to the external style sheet is placed after the internal style sheet in HTML <head>, the external style sheet will override the internal style sheet!

Background Color

The background-color property specifies the background color of an element.

The background color of a page is defined in the body selector:

Example

body {background-color:#b0c4de;}

Try it yourself »

With CSS, a color is most often specified by:

• a HEX value - like "#ff0000"
• an RGB value - like "rgb(255,0,0)"
• a color name - like "red"

Look at CSS Color Values for a complete list of possible color values.

In the example below, the h1, p, and div elements have different background colors:

Example

h1 {background-color:#6495ed;}
p {background-color:#e0ffff;}
div {background-color:#b0c4de;}

Try it yourself »

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Background Image

The background-image property specifies an image to use as the background of an element.

By default, the image is repeated so it covers the entire element.

The background image for a page can be set like this:

Example

body {background-image:url('paper.gif');}

Try it yourself »

Below is an example of a bad combination of text and background image. The text is almost not readable:

Example

body {background-image:url('bgdesert.jpg');}

Try it yourself »

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Background Image - Repeat Horizontally or Vertically

By default, the background-image property repeats an image both horizontally and vertically.

Some images should be repeated only horizontally or vertically, or they will look strange, like this: 

Example

body
{
background-image:url('gradient2.png');
}

Try it yourself »

If the image is repeated only horizontally (repeat-x), the background will look better:

Example

body
{
background-image:url('gradient2.png');
background-repeat:repeat-x;
}

Try it yourself »

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Background Image - Set position and no-repeat

 When using a background image, use an image that does not disturb the text.

Showing the image only once is specified by the background-repeat property:

Example

body
{
background-image:url('img_tree.png');
background-repeat:no-repeat;
}

Try it yourself »

In the example above, the background image is shown in the same place as the text. We want to change the position of the image, so that it does not disturb the text too much.

The position of the image is specified by the background-position property:

Example

body
{
background-image:url('img_tree.png');
background-repeat:no-repeat;
background-position:right top;
}

Try it yourself »

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Background - Shorthand property

As you can see from the examples above, there are many properties to consider when dealing with backgrounds.

To shorten the code, it is also possible to specify all the properties in one single property. This is called a shorthand property.

The shorthand property for background is simply "background":

Example

body {background:#ffffff url('img_tree.png') no-repeat right top;}

Try it yourself »

When using the shorthand property the order of the property values is:

• background-color
• background-image
• background-repeat
• background-attachment
• background-position

TEXT FORMATTING

This text is styled with some of the text formatting properties. The heading uses the text-align, text-transform, and color properties. The paragraph is indented, aligned, and the space between characters is specified. The underline is removed from the "Try it yourself" link.

Text Color

The color property is used to set the color of the text.

With CSS, a color is most often specified by:

• a HEX value - like "#ff0000"
• an RGB value - like "rgb(255,0,0)"
• a color name - like "red"

Look at CSS Color Values for a complete list of possible color values.

The default color for a page is defined in the body selector.

Example

body {color:blue;}
h1 {color:#00ff00;}
h2 {color:rgb(255,0,0);}

Try it yourself »

 For W3C compliant CSS: If you define the color property, you must also define the background-color property.

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Text Alignment

The text-align property is used to set the horizontal alignment of a text.

Text can be centered, or aligned to the left or right, or justified.

When text-align is set to "justify", each line is stretched so that every line has equal width, and the left and right margins are straight (like in magazines and newspapers).

Example

h1 {text-align:center;}
p.date {text-align:right;}
p.main {text-align:justify;}

Try it yourself »

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Text Decoration

The text-decoration property is used to set or remove decorations from text.

The text-decoration property is mostly used to remove underlines from links for design purposes:

Example

a {text-decoration:none;}

Try it yourself »

It can also be used to decorate text:

Example

h1 {text-decoration:overline;}
h2 {text-decoration:line-through;}
h3 {text-decoration:underline;}

Try it yourself »

 It is not recommended to underline text that is not a link, as this often confuses users.

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Text Transformation

The text-transform property is used to specify uppercase and lowercase letters in a text.

It can be used to turn everything into uppercase or lowercase letters, or capitalize the first letter of each word.

Example

p.uppercase {text-transform:uppercase;}
p.lowercase {text-transform:lowercase;}
p.capitalize {text-transform:capitalize;}

Try it yourself »

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Text Indentation

The text-indentation property is used to specify the indentation of the first line of a text.

Example

p {text-indent:50px;}

Try it yourself »

CSS font properties define the font family, boldness, size, and the style of a text.

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Difference Between Serif and Sans-serif Fonts

 On computer screens, sans-serif fonts are considered easier to read than serif fonts.

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CSS Font Families

In CSS, there are two types of font family names:

• generic family - a group of font families with a similar look (like "Serif" or "Monospace")
• font family - a specific font family (like "Times New Roman" or "Arial")

Generic family	Font family	Description
Serif	Times New Roman Georgia	Serif fonts have small lines at the ends on some characters
Sans-serif	Arial Verdana	"Sans" means without - these fonts do not have the lines at the ends of characters
Monospace	Courier New Lucida Console	All monospace characters have the same width

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Font Family

The font family of a text is set with the font-family property.

The font-family property should hold several font names as a "fallback" system. If the browser does not support the first font, it tries the next font.

Start with the font you want, and end with a generic family, to let the browser pick a similar font in the generic family, if no other fonts are available.

Note: If the name of a font family is more than one word, it must be in quotation marks, like font-family: "Times New Roman".

More than one font family is specified in a comma-separated list:

Example

p{font-family:"Times New Roman", Times, serif;}

Try it yourself »

For more commonly used font combinations, look at our Web Safe Font Combinations.

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Font Style

The font-style property is mostly used to specify italic text.

This property has three values:

• normal - The text is shown normally
• italic - The text is shown in italics
• oblique - The text is "leaning" (oblique is very similar to italic, but less supported)

Example

p.normal {font-style:normal;}
p.italic {font-style:italic;}
p.oblique {font-style:oblique;}

Try it yourself »

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Font Size

The font-size property sets the size of the text.

Being able to manage the text size is important in web design. However, you should not use font size adjustments to make paragraphs look like headings, or headings look like paragraphs.

Always use the proper HTML tags, like <h1> - <h6> for headings and <p> for paragraphs.

The font-size value can be an absolute, or relative size.

Absolute size:

• Sets the text to a specified size
• Does not allow a user to change the text size in all browsers (bad for accessibility reasons)
• Absolute size is useful when the physical size of the output is known

Relative size:

• Sets the size relative to surrounding elements
• Allows a user to change the text size in browsers

 If you do not specify a font size, the default size for normal text, like paragraphs, is 16px (16px=1em).

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Set Font Size With Pixels

Setting the text size with pixels gives you full control over the text size:

Example

h1 {font-size:40px;}
h2 {font-size:30px;}
p {font-size:14px;}

Try it yourself »

The example above allows Internet Explorer 9, Firefox, Chrome, Opera, and Safari to resize the text.

Note: The example above does not work in IE, prior version 9.

The text can be resized in all browsers using the zoom tool (however, this resizes the entire page, not just the text).

---

Set Font Size With Em

To avoid the resizing problem with older versions of Internet Explorer, many developers use em instead of pixels.

The em size unit is recommended by the W3C.

1em is equal to the current font size. The default text size in browsers is 16px. So, the default size of 1em is 16px.

The size can be calculated from pixels to em using this formula: pixels/16=em

Example

h1 {font-size:2.5em;} /* 40px/16=2.5em */
h2 {font-size:1.875em;} /* 30px/16=1.875em */
p {font-size:0.875em;} /* 14px/16=0.875em */

Try it yourself »

In the example above, the text size in em is the same as the previous example in pixels. However, with the em size, it is possible to adjust the text size in all browsers.

Unfortunately, there is still a problem with older versions of IE. The text becomes larger than it should when made larger, and smaller than it should when made smaller.

---

Use a Combination of Percent and Em

The solution that works in all browsers, is to set a default font-size in percent for the <body> element:

Example

body {font-size:100%;}
h1 {font-size:2.5em;}
h2 {font-size:1.875em;}
p {font-size:0.875em;}

Try it yourself »

Our code now works great! It shows the same text size in all browsers, and allows all browsers to zoom or resize the text!

Styling Links

Links can be styled with any CSS property (e.g. color, font-family, background, etc.).

Special for links are that they can be styled differently depending on what state they are in.

The four links states are:

• a:link - a normal, unvisited link
• a:visited - a link the user has visited
• a:hover - a link when the user mouses over it
• a:active - a link the moment it is clicked

Example

a:link {color:#FF0000;}      /* unvisited link */
a:visited {color:#00FF00;}  /* visited link */
a:hover {color:#FF00FF;}  /* mouse over link */
a:active {color:#0000FF;}  /* selected link */

Try it yourself »

When setting the style for several link states, there are some order rules:

• a:hover MUST come after a:link and a:visited
• a:active MUST come after a:hover

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Common Link Styles

In the example above the link changes color depending on what state it is in.

Lets go through some of the other common ways to style links:

Text Decoration

The text-decoration property is mostly used to remove underlines from links:

Example

a:link {text-decoration:none;}
a:visited {text-decoration:none;}
a:hover {text-decoration:underline;}
a:active {text-decoration:underline;}

Try it yourself »

Background Color

The background-color property specifies the background color for links:

Example

a:link {background-color:#B2FF99;}
a:visited {background-color:#FFFF85;}
a:hover {background-color:#FF704D;}
a:active {background-color:#FF704D;}

Try it yourself »

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The CSS list properties allow you to:

·         Set different list item markers for ordered lists

·         Set different list item markers for unordered lists

·         Set an image as the list item marker

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List

In HTML, there are two types of lists:

• unordered lists - the list items are marked with bullets
• ordered lists - the list items are marked with numbers or letters

With CSS, lists can be styled further, and images can be used as the list item marker.

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Different List Item Markers

The type of list item marker is specified with the list-style-type property:

Example

ul.a {list-style-type: circle;}
ul.b {list-style-type: square;}

ol.c {list-style-type: upper-roman;}
ol.d {list-style-type: lower-alpha;}

Try it yourself »

Some of the values are for unordered lists, and some for ordered lists.

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An Image as The List Item Marker

To specify an image as the list item marker, use the list-style-image property:

Example

ul
{
list-style-image: url('sqpurple.gif');
}

Try it yourself »

The example above does not display equally in all browsers. IE and Opera will display the image-marker a little bit higher than Firefox, Chrome, and Safari.

If you want the image-marker to be placed equally in all browsers, a crossbrowser solution is explained below.

Crossbrowser Solution

The following example displays the image-marker equally in all browsers:

Example

ul
{
list-style-type: none;
padding: 0px;
margin: 0px;
}
ul li
{
background-image: url(sqpurple.gif);
background-repeat: no-repeat;
background-position: 0px 5px;
padding-left: 14px;
}

Try it yourself »

Example explained:

• For ul:
• Set the list-style-type to none to remove the list item marker
• Set both padding and margin to 0px (for cross-browser compatibility)
• For all li in ul:
• Set the URL of the image, and show it only once (no-repeat)
• Position the image where you want it (left 0px and down 5px)
• Position the text in the list with padding-left

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List - Shorthand property

It is also possible to specify all the list properties in one, single property. This is called a shorthand property.

The shorthand property used for lists, is the list-style property:

Example

ul
{
list-style: square url("sqpurple.gif");
}

Try it yourself »

When using the shorthand property, the order of the values are:

• list-style-type
• list-style-position (for a description, see the CSS properties table below)
• list-style-image

It does not matter if one of the values above are missing, as long as the rest are in the specified order.

The look of an HTML table can be greatly improved with CSS:

Company	Contact	Country
Alfreds Futterkiste	Maria Anders	Germany
Berglunds snabbköp	Christina Berglund	Sweden
Centro comercial Moctezuma	Francisco Chang	Mexico
Ernst Handel	Roland Mendel	Austria
Island Trading	Helen Bennett	UK
Königlich Essen	Philip Cramer	Germany
Laughing Bacchus Winecellars	Yoshi Tannamuri	Canada
Magazzini Alimentari Riuniti	Giovanni Rovelli	Italy
North/South	Simon Crowther	UK
Paris spécialités	Marie Bertrand	France
The Big Cheese	Liz Nixon	USA
Vaffeljernet	Palle Ibsen	Denmark

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Table Borders

To specify table borders in CSS, use the border property.

The example below specifies a black border for table, th, and td elements:

Example

table, th, td
{
border: 1px solid black;
}

Try it yourself »

Notice that the table in the example above has double borders. This is because both the table and the th/td elements have separate borders.

To display a single border for the table, use the border-collapse property.

Collapse Borders

The border-collapse property sets whether the table borders are collapsed into a single border or separated:

Example

table
{
border-collapse:collapse;
}
table,th, td
{
border: 1px solid black;
}

Try it yourself »

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Table Width and Height

Width and height of a table is defined by the width and height properties.

The example below sets the width of the table to 100%, and the height of the th elements to 50px:

Example

table 
{
width:100%;
}
th
{
height:50px;
}

Try it yourself »

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Table Text Alignment

The text in a table is aligned with the text-align and vertical-align properties.

The text-align property sets the horizontal alignment, like left, right, or center:

Example

td
{
text-align:right;
}

Try it yourself »

The vertical-align property sets the vertical alignment, like top, bottom, or middle:

Example

td
{
height:50px;
vertical-align:bottom;
}

Try it yourself »

---

Table Padding

To control the space between the border and content in a table, use the padding property on td and th elements:

Example

td
{
padding:15px;
}

Try it yourself »

---

Table Color

The example below specifies the color of the borders, and the text and background color of th elements:

Example

table, td, th
{
border:1px solid green;
}
th
{
background-color:green;
color:white;
}

Try it yourself »

The CSS Box Model

All HTML elements can be considered as boxes. In CSS, the term "box model" is used when talking about design and layout.

The CSS box model is essentially a box that wraps around HTML elements, and it consists of: margins, borders, padding, and the actual content.

The box model allows us to place a border around elements and space elements in relation to other elements.

The image below illustrates the box model:

Explanation of the different parts:

• Margin - Clears an area around the border. The margin does not have a background color, it is completely transparent
• Border - A border that goes around the padding and content. The border is affected by the background color of the box
• Padding - Clears an area around the content. The padding is affected by the background color of the box
• Content - The content of the box, where text and images appear

In order to set the width and height of an element correctly in all browsers, you need to know how the box model works.

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Width and Height of an Element

 Important: When you set the width and height properties of an element with CSS, you just set the width and height of the content area. To calculate the full size of an element, you must also add the padding, borders and margins.

The total width of the element in the example below is 300px:

width:250px;
padding:10px;
border:5px solid gray;
margin:10px;

Let's do the math:
250px (width)
+ 20px (left + right padding)
+ 10px (left + right border)
+ 20px (left + right margin)
= 300px

Assume that you had only 250px of space. Let's make an element with a total width of 250px:

Example

width:220px;
padding:10px;
border:5px solid gray;
margin:0px;

Try it yourself »

The total width of an element should be calculated like this:

Total element width = width + left padding + right padding + left border + right border + left margin + right margin

The total height of an element should be calculated like this:

Total element height = height + top padding + bottom padding + top border + bottom border + top margin + bottom margin

---

Browsers Compatibility Issue

IE8 and earlier versions of IE, included padding and border in the width property.

To fix this problem, add a <!DOCTYPE html> to the HTML page.

Next Chapter »

CSS Border Properties

The CSS border properties allow you to specify the style and color of an element's border.

Border Style

The border-style property specifies what kind of border to display.

 None of the border properties will have ANY effect unless the border-style property is set!

border-style values:

none: Defines no border

dotted: Defines a dotted border

dashed: Defines a dashed border

solid: Defines a solid border

double: Defines two borders. The width of the two borders are the same as the border-width value

groove: Defines a 3D grooved border. The effect depends on the border-color value

ridge: Defines a 3D ridged border. The effect depends on the border-color value

inset: Defines a 3D inset border. The effect depends on the border-color value

outset: Defines a 3D outset border. The effect depends on the border-color value

Try it yourself: Set the style of the border

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Border Width

The border-width property is used to set the width of the border.

The width is set in pixels, or by using one of the three pre-defined values: thin, medium, or thick.

Note: The "border-width" property does not work if it is used alone. Use the "border-style" property to set the borders first.

Example

p.one
{
border-style:solid;
border-width:5px;
}
p.two
{
border-style:solid;
border-width:medium;
}

Try it yourself »

---

Border Color

The border-color property is used to set the color of the border. The color can be set by:

• name - specify a color name, like "red"
• RGB - specify a RGB value, like "rgb(255,0,0)"
• Hex - specify a hex value, like "#ff0000"

You can also set the border color to "transparent".

Note: The "border-color" property does not work if it is used alone. Use the "border-style" property to set the borders first.

Example

p.one
{
border-style:solid;
border-color:red;
}
p.two
{
border-style:solid;
border-color:#98bf21;
}

Try it yourself »

---

Border - Individual sides

In CSS it is possible to specify different borders for different sides:

Example

p
{
border-top-style:dotted;
border-right-style:solid;
border-bottom-style:dotted;
border-left-style:solid;
}

Try it yourself »

The example above can also be set with a single property:

Example

border-style:dotted solid;

Try it yourself »

The border-style property can have from one to four values.

• border-style:dotted solid double dashed;
• top border is dotted
• right border is solid
• bottom border is double
• left border is dashed

• border-style:dotted solid double;
• top border is dotted
• right and left borders are solid
• bottom border is double

• border-style:dotted solid;
• top and bottom borders are dotted
• right and left borders are solid

• border-style:dotted;
• all four borders are dotted

The border-style property is used in the example above. However, it also works with border-width and border-color.

The CSS margin properties define the space around elements.

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Margin

The margin clears an area around an element (outside the border). The margin does not have a background color, and is completely transparent.

The top, right, bottom, and left margin can be changed independently using separate properties. A shorthand margin property can also be used, to change all margins at once.

Possible Values

Value	Description
auto	The browser calculates a margin
length	Specifies a margin in px, pt, cm, etc. Default value is 0px
%	Specifies a margin in percent of the width of the containing element
inherit	Specifies that the margin should be inherited from the parent element

 It is possible to use negative values, to overlap content.

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Margin - Individual sides

In CSS, it is possible to specify different margins for different sides:

Example

margin-top:100px;
margin-bottom:100px;
margin-right:50px;
margin-left:50px;

Try it yourself »

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Margin - Shorthand property

To shorten the code, it is possible to specify all the margin properties in one property. This is called a shorthand property.

The shorthand property for all the margin properties is "margin":

Example

margin:100px 50px;

Try it yourself »

The margin property can have from one to four values.

• margin:25px 50px 75px 100px;
• top margin is 25px
• right margin is 50px
• bottom margin is 75px
• left margin is 100px

• margin:25px 50px 75px;
• top margin is 25px
• right and left margins are 50px
• bottom margin is 75px

• margin:25px 50px;
• top and bottom margins are 25px
• right and left margins are 50px
• margin:25px;
• all four margins are 25px

Border - Shorthand property

As you can see from the examples above, there are many properties to consider when dealing with borders.

To shorten the code, it is also possible to specify all the individual border properties in one property. This is called a shorthand property.

The border property is a shorthand for the following individual border properties:

• border-width
• border-style (required)
• border-color

Example

border:5px solid red;

Try it yourself »

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he CSS padding properties define the space between the element border and the element content.

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Padding

The padding clears an area around the content (inside the border) of an element. The padding is affected by the background color of the element.

The top, right, bottom, and left padding can be changed independently using separate properties. A shorthand padding property can also be used, to change all paddings at once.

Possible Values

Value	Description
length	Defines a fixed padding (in pixels, pt, em, etc.)
%	Defines a padding in % of the containing element

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Padding - Individual sides

In CSS, it is possible to specify different padding for different sides:

Example

padding-top:25px;
padding-bottom:25px;
padding-right:50px;
padding-left:50px;

Try it yourself »

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Padding - Shorthand property

To shorten the code, it is possible to specify all the padding properties in one property. This is called a shorthand property.

The shorthand property for all the padding properties is "padding":

Example

padding:25px 50px;

Try it yourself »

The padding property can have from one to four values.

• padding:25px 50px 75px 100px;
• top padding is 25px
• right padding is 50px
• bottom padding is 75px
• left padding is 100px

• padding:25px 50px 75px;
• top padding is 25px
• right and left paddings are 50px
• bottom padding is 75px

• padding:25px 50px;
• top and bottom paddings are 25px
• right and left paddings are 50px
• padding:25px;
• all four paddings are 25px

Grouping Selectors

In style sheets there are often elements with the same style.

h1
{
color:green;
}
h2
{
color:green;
}
p
{
color:green;
}

To minimize the code, you can group selectors.

Separate each selector with a comma.

In the example below we have grouped the selectors from the code above:

Example

h1,h2,p
{
color:green;
}

Try it yourself »

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Nesting Selectors

It is possible to apply a style for a selector within a selector.

In the example below, one style is specified for all p elements, one style is specified for all elements with class="marked", and a third style is specified only for p elements within elements with class="marked":

Example

p
{
color:blue;
text-align:center;
}
.marked
{
background-color:red;
}
.marked p
{
color:white;
}

Try it yourself »

he display property specifies if/how an element is displayed, and the visibility property specifies if an element should be visible or hidden.

Box 1

Box 2
 

Box 3
 

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Hiding an Element - display:none or visibility:hidden

Hiding an element can be done by setting the display property to "none" or the visibility property to "hidden". However, notice that these two methods produce different results:

visibility:hidden hides an element, but it will still take up the same space as before. The element will be hidden, but still affect the layout.

Example

h1.hidden {visibility:hidden;}

Try it yourself »

display:none hides an element, and it will not take up any space. The element will be hidden, and the page will be displayed as if the element is not there:

Example

h1.hidden {display:none;}

Try it yourself »

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CSS Display - Block and Inline Elements

A block element is an element that takes up the full width available, and has a line break before and after it.

Examples of block elements:

• <h1>
• <p>
• <div>

An inline element only takes up as much width as necessary, and does not force line breaks.

Examples of inline elements:

• <span>
• <a>

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Changing How an Element is Displayed

Changing an inline element to a block element, or vice versa, can be useful for making the page look a specific way, and still follow web standards.

The following example displays list items as inline elements:

Example

li {display:inline;}

Try it yourself »

The following example displays span elements as block elements:

Example

span {display:block;}

Try it yourself »

Note: Changing the display type of an element changes only how the element is displayed, NOT what kind of element it is. For example: An inline element set to display:block is not allowed to have a block element nested inside of it.