const s1: JJStyleConfig = 'p { color: red; }' // simple string
const s2: JJStyleConfig = cssToSheet('p { color: red; }') // Parse string to CSSStyleSheet
const s3: JJStyleConfig = await fetchCss('./style.css') // Eager loading
const s4: JJStyleConfig = fetchCss('./style.css') // Lazy loading
const s5: JJStyleConfig = () => fetchCss('./style.css') // Lazy loading
Configuration for the component's styles. Can be a CSS string, a CSSStyleSheet, or a Promise / factory that yields one of those.