Gets the CSS code of the site's theme.
Use getSiteThemeHtml() to get an HTML element containing the CSS code of a site's
theme colors and fonts.
Use getSiteThemeHtml() when embedding a custom element in a Wix site where the page's stylesheet
is inaccessible, such as when using a shadow root or an internal iframe.
The options used when getting the HTML element.
This method doesn't return any custom errors, but may return standard errors. Learn more about standard Wix errors.