An outline is a line drawn outside the element's border.
CSS Outline
An outline is a line that is drawn around elements, OUTSIDE the borders, to make the element "stand out".
CSS has the following outline properties:
outline-style
outline-color
outline-width
outline-offset
outline
CSS Outline Style
The outline-style
property specifies the style of the outline, and can have one of the following values:
dotted
- Defines a dotted outlinedashed
- Defines a dashed outlinesolid
- Defines a solid outlinedouble
- Defines a double outlinegroove
- Defines a 3D grooved outlineridge
- Defines a 3D ridged outlineinset
- Defines a 3D inset outlineoutset
- Defines a 3D outset outlinenone
- Defines no outlinehidden
- Defines a hidden outline
The following example shows the different outline-style
values:
Example
Demonstration of the different outline styles:
p.dotted {outline-style: dotted;}
p.dashed {outline-style: dashed;}
p.solid {outline-style: solid;}
p.double {outline-style: double;}
p.groove {outline-style: groove;}
p.ridge {outline-style: ridge;}
p.inset {outline-style: inset;}
p.outset {outline-style: outset;}
Result:
A dotted outline.
A dashed outline.
A solid outline.
A double outline.
A groove outline. The effect depends on the outline-color value.
A ridge outline. The effect depends on the outline-color value.
An inset outline. The effect depends on the outline-color value.
An outset outline. The effect depends on the outline-color value.
Note: None of the other outline properties (which you will learn more about in the next chapters) will have ANY effect unless the outline-style
property is set!
CSS Outline Width
The outline-width
property specifies the width of the outline, and can have one of the following values:
- thin (typically 1px)
- medium (typically 3px)
- thick (typically 5px)
- A specific size (in px, pt, cm, em, etc)
The following example shows some outlines with different widths:
A thin outline.
A medium outline.
A thick outline.
A 4px thick outline.
Example
p.ex1 {
border: 1px solid black;
outline-style: solid;
outline-color: red;
outline-width: thin;
}
p.ex2 {
border: 1px solid black;
outline-style: solid;
outline-color: red;
outline-width: medium;
}
p.ex3 {
border: 1px solid black;
outline-style: solid;
outline-color: red;
outline-width: thick;
}
p.ex4 {
border: 1px solid black;
outline-style: solid;
outline-color: red;
outline-width: 4px;
}
CSS Outline Color
The outline-color
property is used to set the color of the outline.
The color can be set by:
- name - specify a color name, like "red"
- HEX - specify a hex value, like "#ff0000"
- RGB - specify a RGB value, like "rgb(255,0,0)"
- HSL - specify a HSL value, like "hsl(0, 100%, 50%)"
- invert - performs a color inversion (which ensures that the outline is visible, regardless of color background)
The following example shows some different outlines with different colors. Also notice that these elements also have a thin black border inside the outline:
A solid red outline.
A dotted blue outline.
An outset grey outline.
Example
p.ex1 {
border: 2px solid black;
outline-style: solid;
outline-color: red;
}
p.ex2 {
border: 2px solid black;
outline-style: dotted;
outline-color: blue;
}
p.ex3 {
border: 2px solid black;
outline-style: outset;
outline-color: grey;
}
HEX Values
The outline color can also be specified using a hexadecimal value (HEX):
Example
p.ex1 {
outline-style: solid;
outline-color: #ff0000; /* red */
}
RGB Values
Or by using RGB values:
Example
p.ex1 {
outline-style: solid;
outline-color: rgb(255, 0, 0); /* red */
}
HSL Values
You can also use HSL values:
Example
p.ex1 {
outline-style: solid;
outline-color: hsl(0, 100%, 50%); /* red */
}
CSS Outline - Shorthand property
The outline
property is a shorthand property for setting the following individual outline properties:
outline-width
outline-style
(required)outline-color
The outline
property is specified as one, two, or three values from the list above. The order of the values does not matter.
The following example shows some outlines specified with the shorthand outline
property:
A dashed outline.
A dotted red outline.
A 5px solid yellow outline.
A thick ridge pink outline.
Example
p.ex1 {outline: dashed;}
p.ex2 {outline: dotted red;}
p.ex3 {outline: 5px solid yellow;}
p.ex4 {outline: thick ridge pink;}
CSS Outline Offset
The outline-offset
property adds space between an outline and the edge/border of an element. The space between an element and its outline is transparent.
The following example specifies an outline 15px outside the border edge:
This paragraph has an outline 15px outside the border edge.
Example
p {
margin: 30px;
border: 1px solid black;
outline: 1px solid red;
outline-offset: 15px;
}
The following example shows that the space between an element and its outline is transparent:
This paragraph has an outline of 15px outside the border edge.
Example
p {
margin: 30px;
background: yellow;
border: 1px solid black;
outline: 1px solid red;
outline-offset: 15px;
}
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