CSS - @namespace

@namespace is an at-rule used for specifying XML namespaces to be utilized in a CSS style sheet.

  • XML namespaces are created via the @namespace rule and used in CSS style sheets.

  • In documents having numerous namespaces, such as HTML paired with inline SVG or MathML, or mixed XML vocabularies, these namespaces might confine selections to certain items inside that namespace.

  • Namespace declarations made using the @namespace macro must occur before other at-rules and style declarations in the style sheet and adhere to the @charset and @import rules.

  • The default namespace for the style sheet may be set using @namespace. With a default namespace, universal and type selectors (with the exception of attribute selectors) only apply to items inside that namespace.

  • A namespace prefix can also be defined using the @namespace rule. When a namespace prefix is prefixed to a universal, type, or attribute selector, the selection only matches if the namespace and name of the element or attribute match.

  • In HTML, namespaces are automatically given to recognized foreign components. As a result, even if the page doesn't have any instances of the xmlns property.

  • HTML components will behave as though they are in the XHTML namespace, and the svg and math elements will be given their appropriate namespaces.

Example

The following example demonstrates use of @namespace.

<html>
<head>
<style>
    @namespace svg url('http://www.w3.org/2000/svg');
    body {
        font-family: Arial, sans-serif;
        background-color: #f0f0f0;
    }
    .html-link {
        color: green;
        text-decoration: underline;
        font-weight: bold;
    }
    svg|a {
        fill: navy;
        text-decoration: underline;
        font-weight: bold;
    }
</style>
</head>
<body>
<p><a href="#" class="html-link">This is a regular HTML link</a></p>
<svg width="250px" viewBox="0 0 250 20" xmlns="http://www.w3.org/2000/svg">
    <a href="#">
        <text x="0" y="15">This is a link created in SVG</text>
    </a>
</svg>
</body>
</html>
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