CSS1 Properties

Font Properties

Color and Background Properties

Text Properties

Box Properties

Classification Properties

Units

Syntax Used in Property Definitions

<Foo>: Value of type Foo. Common types are discussed in the Units section.
Foo: A keyword that must appear literally (though without case sensitivity). Commas and slashes must also appear literally.
A B C: A must occur, then B, then C, in that order.
A | B: A or B must occur.
A || B: A or B or both must occur, in any order.
[ Foo ]: Brackets are used to group items together.
Foo*: Foo is repeated zero or more times.
Foo+: Foo is repeated one or more times.
Foo?: Foo is optional.
Foo{A,B}: Foo must occur at least A times and at most B times.

Font Family

Syntax:	font-family: [[<family-name> \| <generic-family>],]* [<family-name> \| <generic-family>]
Possible Values:	<family-name> Any font family name may be used <generic-family> serif (e.g., Times) sans-serif (e.g., Arial or Helvetica) cursive (e.g., Zapf-Chancery) fantasy (e.g., Western) monospace (e.g., Courier)
Initial Value:	Determined by browser
Applies to:	All elements
Inherited:	Yes

Font families may be assigned by a specific font name or a generic font family. Obviously, defining a specific font will not be as likely to match as a generic font family. Multiple family assignments can be made, and if a specific font assignment is made it should be followed by a generic family name in case the first choice is not present.

A sample font-family declaration might look like this:

P { font-family: "New Century Schoolbook", Times, serif }

Notice that the first two assignments are specific type faces: New Century Schoolbook and Times. However, since both of them are serif fonts, the generic font family is listed as a backup in case the system does not have either of these but has another serif font which meets the qualifications.

Any font name containing whitespace must be quoted, with either single or double quotes.

The font family may also be given with the font property.

Font Style

Syntax:	font-style: <value>
Possible Values:	normal \| italic \| oblique
Initial Value:	normal
Applies to:	All elements
Inherited:	Yes

The font-style property defines that the font be displayed in one of three ways: normal, italic or oblique (slanted). A sample style sheet with font-style declarations might look like this:

H1 { font-style: oblique }
P { font-style: normal }

Font Variant

Syntax:	font-variant: <value>
Possible Values:	normal \| small-caps
Initial Value:	normal
Applies to:	All elements
Inherited:	Yes

The font-variant property determines if the font is to display in normal or small-caps. Small-caps are displayed when all the letters of the word are in capitals with uppercase characters slightly larger than lowercase. Later versions of CSS may support additional variants such as condensed, expanded, small-caps numerals or other custom variants. An example of a font-variant assignment would be:

SPAN { font-variant: small-caps }

Font Weight

Syntax:	font-weight: <value>
Possible Values:	normal \| bold \| bolder \| lighter \| 100 \| 200 \| 300 \| 400 \| 500 \| 600 \| 700 \| 800 \| 900
Initial Value:	normal
Applies to:	All elements
Inherited:	Yes

The font-weight property is used to specify the weight of the font. The bolder and lighter values are relative to the inherited font weight, while the other values are absolute font weights.

Note: Since not all fonts have nine possible display weights some of the weights may be grouped together in assignment. If the specified weight is not available, an alternate will be chosen on the following basis:

500 may be switched with 400, and vice versa
100-300 may be assigned to the next lighter weight, if any, or the next darker weight otherwise
600-900 may be assigned to the next darker weight, if any, or the next lighter weight otherwise

Some example font-weight assignments would be:

H1 { font-weight: 800 }
P { font-weight: normal }

Syntax:	font-size: <absolute-size> \| <relative-size> \| <length> \| <percentage>
Possible Values:	<absolute-size> xx-small \| x-small \| small \| medium \| large \| x-large \| xx-large <relative-size> larger \| smaller <length> <percentage> (in relation to parent element)
Initial Value:	medium
Applies to:	All elements
Inherited:	Yes

The font-size property is used to modify the size of the displayed font. Absolute lengths (using units like pt and in) should be used sparingly due to their weakness in adapting to different browsing environments. Fonts with absolute lengths can very easily be too small or too large for a user.

Some example size assignments would be:

H1 { font-size: large }
P { font-size: 12pt }
LI { font-size: 90% }
STRONG { font-size: larger }

Authors should be aware that Microsoft Internet Explorer 3.x incorrectly treats em and ex units as pixels, which can easily make text using these units unreadable. The browser also incorrectly applies percentage values relative to its default font size for the selector, rather than relative to the parent element's font size. This makes rules like

H1 { font-size: 200% }

dangerous in that the size will be twice IE's default font size for level-one headings, rather than twice the parent element's font size. In this case, BODY would most likely be the parent element, and it would likely define a medium font size, whereas the default level-one heading font size imposed by IE would probably be considered xx-large.

Given these bugs, authors should take care in using percentage values for font-size, and should probably avoid em and ex units for this property.

Font

Syntax:	font: <value>
Possible Values:	[ <font-style> \|\| <font-variant> \|\| <font-weight> ]? <font-size> [ / <line-height> ]? <font-family>
Initial Value:	Not defined
Applies to:	All elements
Inherited:	Yes

The font property may be used as a shorthand for the various font properties, as well as the line height. For example,

P { font: italic bold 12pt/14pt Times, serif }

specifies paragraphs with a bold and italic Times or serif font with a size of 12 points and a line height of 14 points.

Color and Background Properties

Color
Background Color
Background Image
Background Repeat
Background Attachment
Background Position
Background

Color

Syntax:	color: <color>
Initial Value:	Determined by browser
Applies to:	All elements
Inherited:	Yes

The color property allows authors to specify the color of an element. See the Units section for color value descriptions. Some example color rules include:

H1 { color: blue }
H2 { color: #000080 }
H3 { color: #0c0 }

To help avoid conflicts with user style sheets, background and color properties should always be specified together.

Background Color

Syntax:	background-color: <value>
Possible Values:	<color> \| transparent
Initial Value:	transparent
Applies to:	All elements
Inherited:	No

The background-color property sets the background color of an element. For example:

BODY { background-color: white }
H1 { background-color: #000080 }

To help avoid conflicts with user style sheets, background-image should be specified whenever background-color is used. In most cases, background-image: none is suitable.

Authors may also use the shorthand background property, which is currently better supported than the background-color property.

Background Image

Syntax:	background-image: <value>
Possible Values:	<url> \| none
Initial Value:	none
Applies to:	All elements
Inherited:	No

The background-image property sets the background image of an element. For example:

BODY { background-image: url(/images/foo.gif) }
P { background-image: url(http://www.htmlhelp.com/bg.png) }

When a background image is defined, a similar background color should also be defined for those not loading images.

Authors may also use the shorthand background property, which is currently better supported than the background-image property.

Background Repeat

Syntax:	background-repeat: <value>
Possible Values:	repeat \| repeat-x \| repeat-y \| no-repeat
Initial Value:	repeat
Applies to:	All elements
Inherited:	No

The background-repeat property determines how a specified background image is repeated. The repeat-x value will repeat the image horizontally while the repeat-y value will repeat the image vertically. For example:

BODY { background: white url(candybar.gif);
background-repeat: repeat-x }

In the above example, the image will only be tiled horizontally.

Authors may also use the shorthand background property, which is currently better supported than the background-repeat property.

Background Attachment

Syntax:	background-attachment: <value>
Possible Values:	scroll \| fixed
Initial Value:	scroll
Applies to:	All elements
Inherited:	No

The background-attachment property determines if a specified background image will scroll with the content or be fixed with regard to the canvas. For example, the following specifies a fixed background image:

BODY { background: white url(candybar.gif);
background-attachment: fixed }

Authors may also use the shorthand background property, which is currently better supported than the background-attachment property.

Background Position

Syntax:	background-position: <value>
Possible Values:	[<percentage> \| <length>]{1,2} \| [top \| center \| bottom] \|\| [left \| center \| right]
Initial Value:	0% 0%
Applies to:	Block-level and replaced elements
Inherited:	No

The background-position property gives the initial position of a specified background image. This property may only be applied to block-level elements and replaced elements. (A replaced element is one for which only the intrinsic dimensions are known; HTML replaced elements include IMG, INPUT, TEXTAREA, SELECT, and OBJECT.)

The easiest way to assign a background position is with keywords:

Horizontal keywords (left, center, right)
Vertical keywords (top, center, bottom)

Percentages and lengths may also be used to assign the position of the background image. Percentages are relative to the size of the element. Although lengths are allowed, they are not recommended due to their inherent weakness in dealing with differing display resolutions.

When using percentages or lengths, the horizontal position is specified first, followed by the vertical position. A value such as 20% 65% specifies that the point 20% across and 65% down the image be placed at the point 20% across and 65% down the element. A value such as 5px 10px specifies that the upper left corner of the image be placed 5 pixels to the right of and 10 pixels below the upper left corner of the element.

If only the horizontal value is given, the vertical position will be 50%. Combinations of lengths and percentages are allowed, as are negative positions. For example, 10% -2cm is permitted. However, percentages and lengths cannot be combined with keywords.

The keywords are interpreted as follows:

top left = left top = 0% 0%
top = top center = center top = 50% 0%
right top = top right = 100% 0%
left = left center = center left = 0% 50%
center = center center = 50% 50%
right = right center = center right = 100% 50%
bottom left = left bottom = 0% 100%
bottom = bottom center = center bottom = 50% 100%
bottom right = right bottom = 100% 100%

If the background image is fixed with regard to the canvas, the image is placed relative to the canvas instead of the element.

Authors may also use the shorthand background property, which is currently better supported than the background-position property.

Background

Syntax:	background: <value>
Possible Values:	<background-color> \|\| <background-image> \|\| <background-repeat> \|\| <background-attachment> \|\| <background-position>
Initial Value:	Not defined
Applies to:	All elements
Inherited:	No

The background property is a shorthand for the more specific background-related properties. Some examples of background declarations follow:

BODY { background: white url(http://www.htmlhelp.com/foo.gif) }
BLOCKQUOTE { background: #7fffd4 }
P { background: url(../backgrounds/pawn.png) #f0f8ff fixed }
TABLE { background: #0c0 url(leaves.jpg) no-repeat bottom right }

A value not specified will receive its initial value. For example, in the first three rules above, the background-position property will be set to 0% 0%.

To help avoid conflicts with user style sheets, background and color properties should always be specified together.

Text Properties

Word Spacing
Letter Spacing
Text Decoration
Vertical Alignment
Text Transformation
Text Alignment
Text Indentation
Line Height

Word Spacing

Syntax:	word-spacing: <value>
Possible Values:	normal \| <length>
Initial Value:	normal
Applies to:	All elements
Inherited:	Yes

The word-spacing property defines an additional amount of space between words. The value must be in the length format; negative values are permitted.

Examples:

P EM { word-spacing: 0.4em } P.note { word-spacing: -0.2em }

Letter Spacing

Syntax:	letter-spacing: <value>
Possible Values:	normal \| <length>
Initial Value:	normal
Applies to:	All elements
Inherited:	Yes

The letter-spacing property defines an additional amount of space between characters. The value must be in the length format; negative values are permitted. A setting of 0 will prevent justification.

Examples:

H1 { letter-spacing: 0.1em }
P.note { letter-spacing: -0.1em }

Text Decoration

Syntax:	text-decoration: <value>
Possible Values:	none \| [ underline \|\| overline \|\| line-through \|\| blink ]
Initial Value:	none
Applies to:	All elements
Inherited:	No

The text-decoration property allows text to be decorated through one of five properties: underline, overline, line-through, blink, or the default, none.

For example, one can suggest that links not be underlined with

A:link, A:visited, A:active { text-decoration: none }

Vertical Alignment

Syntax:	vertical-align: <value>
Possible Values:	baseline \| sub \| super \| top \| text-top \| middle \| bottom \| text-bottom \| <percentage>
Initial Value:	baseline
Applies to:	Inline elements
Inherited:	No

The vertical-align property may be used to alter the vertical positioning of an inline element, relative to its parent element or to the element's line. (An inline element is one which has no line break before and after it, for example, EM, A, and IMG in HTML.)

The value may be a percentage relative to the element's line-height property, which would raise the element's baseline the specified amount above the parent's baseline. Negative values are permitted.

The value may also be a keyword. The following keywords affect the positioning relative to the parent element:

baseline (align baselines of element and parent)
middle (align vertical midpoint of element with baseline plus half the x-height--the height of the letter "x"--of the parent)
sub (subscript)
super (superscript)
text-top (align tops of element and parent's font)
text-bottom (align bottoms of element and parent's font)

The keywords affecting the positioning relative to the element's line are

top (align top of element with tallest element on the line)
bottom (align bottom of element with lowest element on the line)

The vertical-align property is particularly useful for aligning images. Some examples follow:

IMG.middle { vertical-align: middle }
IMG { vertical-align: 50% }
.exponent { vertical-align: super }

Text Transformation

Syntax:	text-transform: <value>
Possible Values:	none \| capitalize \| uppercase \| lowercase
Initial Value:	none
Applies to:	All elements
Inherited:	Yes

The text-transform property allows text to be transformed by one of four properties:

capitalize (capitalizes first character of each word)
uppercase (capitalizes all characters of each word)
lowercase (uses small letters for all characters of each word)
none (the initial value)

Examples:

H1 { text-transform: uppercase }
H2 { text-transform: capitalize }

The text-transform property should only be used to express a stylistic desire. It would be inappropriate, for example, to use text-transform to capitalize a list of countries or names.

Text Alignment

Syntax:	text-align: <value>
Possible Values:	left \| right \| center \| justify
Initial Value:	Determined by browser
Applies to:	Block-level elements
Inherited:	Yes

The text-align property can be applied to block-level elements (P, H1, etc.) to give the alignment of the element's text. This property is similar in function to HTML's ALIGN attribute on paragraphs, headings, and divisions.

Some examples follow:

H1 { text-align: center }
P.newspaper { text-align: justify }

Text Indentation

Syntax:	text-indent: <value>
Possible Values:	<length> \| <percentage>
Initial Value:	0
Applies to:	Block-level elements
Inherited:	Yes

The text-indent property can be applied to block-level elements (P, H1, etc.) to define the amount of indentation that the first line of the element should receive. The value must be a length or a percentage; percentages refer to the parent element's width. A common use of text-indent would be to indent a paragraph:

P { text-indent: 5em }

Line Height

Syntax:	line-height: <value>
Possible Values:	normal \| <number> \| <length> \| <percentage>
Initial Value:	normal
Applies to:	All elements
Inherited:	Yes

The line-height property will accept a value to control the spacing between baselines of text. When the value is a number, the line height is calculated by multiplying the element's font size by the number. Percentage values are relative to the element's font size. Negative values are not permitted.

Line height may also be given in the font property along with a font size.

The line-height property could be used to double space text:

P { line-height: 200% }

Microsoft Internet Explorer 3.x incorrectly treats number values and values with em or ex units as pixel values. This bug can easily make pages unreadable, and so authors should avoid provoking it wherever possible; percentage units are often a good choice.

Box Properties

Top Margin
Right Margin
Bottom Margin
Left Margin
Margin
Top Padding
Right Padding
Bottom Padding
Left Padding
Padding
Top Border Width
Right Border Width
Bottom Border Width
Left Border Width
Border Width
Border Color
Border Style
Top Border
Right Border
Bottom Border
Left Border
Border
Width
Height
Float
Clear

Top Margin

Syntax:	margin-top: <value>
Possible Values:	<length> \| <percentage> \| auto
Initial Value:	0
Applies to:	All elements
Inherited:	No

The margin-top property sets the top margin of an element by specifying a length or a percentage. Percentage values refer to the parent element's width. Negative margins are permitted.

For example, the following rule would eliminate the top margin of a document:

BODY { margin-top: 0 }

Note that adjoining vertical margins are collapsed to use the maximum of the margin values.

Right Margin

Syntax:	margin-right: <value>
Possible Values:	<length> \| <percentage> \| auto
Initial Value:	0
Applies to:	All elements
Inherited:	No

The margin-right property sets the right margin of an element by specifying a length or a percentage. Percentage values refer to the parent element's width. Negative margins are permitted.

Example:

P.narrow { margin-right: 50% }

Note that adjoining horizontal margins are not collapsed.

Bottom Margin

Syntax:	margin-bottom: <value>
Possible Values:	<length> \| <percentage> \| auto
Initial Value:	0
Applies to:	All elements
Inherited:	No

The margin-bottom property sets the bottom margin of an element by specifying a length or a percentage. Percentage values refer to the parent element's width. Negative margins are permitted.

Example:

DT { margin-bottom: 3em }

Note that adjoining vertical margins are collapsed to use the maximum of the margin values.

Left Margin

Syntax:	margin-left: <value>
Possible Values:	<length> \| <percentage> \| auto
Initial Value:	0
Applies to:	All elements
Inherited:	No

The margin-left property sets the left margin of an element by specifying a length or a percentage. Percentage values refer to the parent element's width. Negative margins are permitted.

Example:

ADDRESS { margin-left: 50% }

Note that adjoining horizontal margins are not collapsed.

Margin

Syntax:	margin: <value>
Possible Values:	[ <length> \| <percentage> \| auto ]{1,4}
Initial Value:	Not defined
Applies to:	All elements
Inherited:	No

The margin property sets the margins of an element by specifying between one and four values, where each value is a length, a percentage, or auto. Percentage values refer to the parent element's width. Negative margins are permitted.

If four values are given, they apply to top, right, bottom, and left margin, respectively. If one value is given, it applies to all sides. If two or three values are given, the missing values are taken from the opposite side.

Examples of margin declarations include:

BODY { margin: 5em } /* all margins 5em */
P { margin: 2em 4em } /* top and bottom margins 2em,
left and right margins 4em */
DIV { margin: 1em 2em 3em 4em } /* top margin 1em,
right margin 2em,
bottom margin 3em,
left margin 4em */

Note that adjoining vertical margins are collapsed to use the maximum of the margin values. Horizontal margins are not collapsed.

Using the margin property allows one to set all margins; alternatively, the properties margin-top, margin-bottom, margin-left, and margin-right may be used.

Top Padding

Syntax:	padding-top: <value>
Possible Values:	<length> \| <percentage>
Initial Value:	0
Applies to:	All elements
Inherited:	No

The padding-top property describes how much space to put between the top border and the content of the selector. The value is either a length or a percentage. Percentage values refer to the parent element's width. Negative values are not permitted.

Right Padding

Syntax:	padding-right: <value>
Possible Values:	<length> \| <percentage>
Initial Value:	0
Applies to:	All elements
Inherited:	No

The padding-right property describes how much space to put between the right border and the content of the selector. The value is either a length or a percentage. Percentage values refer to the parent element's width. Negative values are not permitted.

Bottom Padding

Syntax:	padding-bottom: <value>
Possible Values:	<length> \| <percentage>
Initial Value:	0
Applies to:	All elements
Inherited:	No

The padding-bottom property describes how much space to put between the bottom border and the content of the selector. The value is either a length or a percentage. Percentage values refer to the parent element's width. Negative values are not permitted.

Left Padding

Syntax:	padding-left: <value>
Possible Values:	<length> \| <percentage>
Initial Value:	0
Applies to:	All elements
Inherited:	No

The padding-left property describes how much space to put between the left border and the content of the selector. The value is either a length or a percentage. Percentage values refer to the parent element's width. Negative values are not permitted.

Padding

Syntax:	padding: <value>
Possible Values:	[ <length> \| <percentage> ]{1,4}
Initial Value:	0
Applies to:	All elements
Inherited:	No

The padding property is a shorthand for the padding-top, padding-right, padding-bottom, and padding-left properties.

An element's padding is the amount of space between the border and the content of the element. Between one and four values are given, where each value is either a length or a percentage. Percentage values refer to the parent element's width. Negative values are not permitted.

If four values are given, they apply to top, right, bottom, and left padding, respectively. If one value is given, it applies to all sides. If two or three values are given, the missing values are taken from the opposite side.

For example, the following rule sets the top padding to 2em, the right padding to 4em, the bottom padding to 5em, and the left padding to 4em:

BLOCKQUOTE { padding: 2em 4em 5em }

Top Border Width

Syntax:	border-top-width: <value>
Possible Values:	thin \| medium \| thick \| <length>
Initial Value:	medium
Applies to:	All elements
Inherited:	No

The border-top-width property is used to specify the width of an element's top border. The value may be one of three keywords, which are not affected by font size, or a length, which can be used to achieve relative widths. Negative values are not allowed.

One may also use the border-top, border-width, or border shorthand properties.

Right Border Width

Syntax:	border-right-width: <value>
Possible Values:	thin \| medium \| thick \| <length>
Initial Value:	medium
Applies to:	All elements
Inherited:	No

The border-right-width property is used to specify the width of an element's right border. The value may be one of three keywords, which are not affected by font size, or a length, which can be used to achieve relative widths. Negative values are not allowed.

One may also use the border-right, border-width, or border shorthand properties.

Bottom Border Width

Syntax:	border-bottom-width: <value>
Possible Values:	thin \| medium \| thick \| <length>
Initial Value:	medium
Applies to:	All elements
Inherited:	No

The border-bottom-width property is used to specify the width of an element's bottom border. The value may be one of three keywords, which are not affected by font size, or a length, which can be used to achieve relative widths. Negative values are not allowed.

One may also use the border-bottom, border-width, or border shorthand properties.

Left Border Width

Syntax:	border-left-width: <value>
Possible Values:	thin \| medium \| thick \| <length>
Initial Value:	medium
Applies to:	All elements
Inherited:	No

The border-left-width property is used to specify the width of an element's left border. The value may be one of three keywords, which are not affected by font size, or a length, which can be used to achieve relative widths. Negative values are not allowed.

One may also use the border-left, border-width, or border shorthand properties.

Border Width

Syntax:	border-width: <value>
Possible Values:	[ thin \| medium \| thick \| <length> ]{1,4}
Initial Value:	Not defined
Applies to:	All elements
Inherited:	No

The border-width property is used to set the border width of an element by specifying between one and four values, where each value is a keyword or a length. Negative lengths are not permitted.

If four values are given, they apply to top, right, bottom, and left border width, respectively. If one value is given, it applies to all sides. If two or three values are given, the missing values are taken from the opposite side.

This property is a shorthand for the border-top-width, border-right-width, border-bottom-width, and border-left-width properties.