Apply a supporter-supplied stylesheet to the current document via
adoptedStyleSheets. Using the Constructable StyleSheet API means
we never need 'unsafe-inline' in style-src — a strict CSP holds
for free users who can't set this field. Empty input is a no-op.
replaceSync parses the whole stylesheet; a parser-fatal error
surfaces in the console but doesn't break the page.
Apply a supporter-supplied stylesheet to the current document via
adoptedStyleSheets. Using the Constructable StyleSheet API means we never need'unsafe-inline'instyle-src— a strict CSP holds for free users who can't set this field. Empty input is a no-op.replaceSyncparses the whole stylesheet; a parser-fatal error surfaces in the console but doesn't break the page.