Boxes Redirect 1

This is the 11th section of the CSS Getting Started tutorial; it describes how you can use CSS to control the space that an element takes up when it is displayed. In your sample document, you change the spacing and add decorative rules.

Information: Boxes

When your browser displays an element, the element takes up space. There are four parts to the space that it takes up.

In the middle, there is the space that the element needs to display its content. Around that, there is padding. Around that, there is a border. Around that, there is a margin that separates the element from other elements.

margin

border

padding

element

The pale gray shows parts of the layout.

 

 

 

element

This is what you see in your browser.

The padding, border and margin can have different sizes on the top, right, bottom and left of the element. Any or all of these sizes can be zero.

Coloring

The padding is always the same color as the element's background. So when you set the background color, you see the color applied to the element itself and its padding. The margin is always transparent.

margin

border

padding

element

The element has a green background.

 

 

 

element

This is what you see in your browser.

Borders

You can use borders to decorate elements with lines or boxes.

To specify the same border all around an element, use the border property. Specify the width (usually in pixels for display on a screen), the style, and the color.

The styles are:

solid
dotted
dashed
double
inset
outset
ridge
groove

You can also set the style to none or hidden to explicitly remove the border, or set the color to transparent to make the border invisible without changing the layout.

To specify borders one side at a time, use the properties: border-top, border-right, border-bottom, border-left. You can use these to specify a border on only one side, or different borders on different sides.

Example

This rule sets the background color and the top border of heading elements:

h3 {
  border-top: 4px solid #7c7; /* mid green */
  background-color: #efe;     /* pale green */
  color: #050;                /* dark green */
  }

The result looks like:

Stylish heading

This rule makes images easier to see by giving them a mid-gray border all round:

img {border: 2px solid #ccc;}

The result looks like:

Image: Image:Blue-rule.png

Margins and padding

Use margins and padding to adjust elements' positions and to create space around them.

Use the margin property or the padding property to set the margin or padding widths respectively.

If you specify one width, it applies all around the element (top, right, bottom and left).

If you specify two widths, the first applies to the top and bottom, the second to the right and left.

You can specify all four widths in the order: top, right, bottom, left.

Example

This rule marks out paragraphs with the class remark by giving them a red border all round.

Padding all round separates the border from the text a little.

A left margin indents the paragraph relative to the rest of the text:

p.remark {
  border: 2px solid red;
  padding: 4px;
  margin-left: 24px;
  }

The result looks like:

Here is a normal paragraph.

Here is a remark.

More details

When you use margins and padding to adjust the way elements are laid out, your style rules interact with the browser's defaults in ways that can be complex.

Different browsers lay elements out differently. The results might look similar until your stylesheet changes things. Sometimes this can make your stylesheet give surprising results.

To get the result you want, you might have to change your document's markup. The next page of this tutorial has more information on this.

For detailed information about padding, margins and borders, see the Box model reference page.

Action: Adding borders

Edit your CSS file, style2.css. Add this rule to draw a line across the page over each heading:

h3 {border-top: 1px solid gray;}

If you took the challenge on the last page, modify the rule you created, otherwise add this new rule to add space underneath each list item:

li {
  list-style: lower-roman;
  margin-bottom: 8px;
  }

Refresh your browser to see the result:

(A) The oceans

  • Arctic
  • Atlantic
  • Pacific
  • Indian
  • Southern

(B) Numbered paragraphs

1: Lorem ipsum

2: Dolor sit

3: Amet consectetuer

4: Magna aliquam

5: Autem veleum

Challenge

Add one rule to your stylesheet, making a wide border all around the oceans in a color that reminds you of the sea—something like this:

(A) The oceans

  • Arctic
  • Atlantic
  • Pacific
  • Indian
  • Southern

(B) Numbered paragraphs

. . .

 

(There is no need to match the width and color you see here exactly.)

See a solution to this challenge.

What next?

By specifying margins and padding, you modified the layout of your document. On the next page you change your document's layout in other ways.

Document Tags and Contributors

Contributors to this page: Sheppy
Last updated by: Sheppy,