🏠 New in High Baseline Support: Constructed stylesheets

September 27, 2025

caniuse · mdn · [spec]([‘https://drafts.csswg.org/cssom-1/#dom-cssstylesheet-cssstylesheet’, ‘https://drafts.csswg.org/cssom-1/#dom-documentorshadowroot-adoptedstylesheets’])

The CSSStyleSheet constructor creates a new stylesheet which can be shared between a document and multiple shadow roots using adoptedStyleSheets.

Source features

• api.CSSStyleSheet.CSSStyleSheet [mdn]
• api.CSSStyleSheet.replace [mdn]
• api.CSSStyleSheet.replaceSync [mdn]
• api.Document.adoptedStyleSheets [mdn]
• api.ShadowRoot.adoptedStyleSheets [mdn]
• api.CSSStyleSheet.CSSStyleSheet.options_baseURL_parameter [mdn]