CSS Outline Width

CSS outline-width is a property used to set the width of the outline around an element. It is one of the individual properties that can be used within the outline shorthand property or on its own if you only need to control the outline's width.

The syntax for the outline-width property is as follows:

        
            selector {
    outline-width: length;
}
        
    

• The selector represents the HTML element or class/id selector to which you want to apply the outline width.
• The length specifies the desired width of the outline. It can be specified using length values (e.g., 1px, 2px, etc.) or any valid CSS length notation.

        
            button {
    outline-width: 2px; /* Sets the outline width to 2 pixels */
}
        
    

In the above example, the button element will have an outline with a width of 2 pixels.

When using the outline shorthand property, the outline-width can be combined with other outline properties like outline-style and outline-color.

Example using outline shorthand:

        
            button {
    outline: 2px dotted red;
}
        
    

It's important to note that the outline-width property does not affect the layout of the element. Unlike the border property, which creates a visible border that affects the box model, the outline property, including outline-width, does not take up any space and is drawn outside the element's dimensions. It is often used to provide visual emphasis, highlight interactive elements, or improve accessibility in focus states.

Keep in mind that the outline property is not supported in Internet Explorer 7 and below, but outline-width itself is generally well-supported by modern browsers. As with any CSS property, it's essential to test for cross-browser compatibility to ensure a consistent user experience.