Part

Pseudo-element

::part(name)

Styles a part of a shadow DOM element that has been exported with the part attribute.

Example

custom-element::part(title) {
  font-size: 1.5em;
  color: navy;
}

Specificity

0-0-1

Browser Support

All modern browsers

About the Part

The ::part(name) CSS selector belongs to the Pseudo-element category.Styles a part of a shadow DOM element that has been exported with the part attribute. Understanding CSS selector specificity and combinators is essential for writing maintainable stylesheets that behave predictably.

The specificity of this selector is 0-0-1. CSS specificity determines which styles are applied when multiple rules target the same element. Higher specificity values take precedence. The specificity hierarchy from lowest to highest is: universal (*) → type/element → class/attribute/pseudo-class → ID → inline styles → !important.

Browser support for Part is: All modern browsers. When using newer CSS selectors like :has(), :is(), or CSS nesting, consider providing fallback styles for older browsers. Use @supports to progressively enhance your stylesheets with modern features while maintaining backward compatibility.

Related Selectors

::slotted(selector)::before ::after