slightly improve output size by refactoring add_css method

src/compiler/compile/render_dom/index.ts

@@ -45,7 +45,7 @@ export default function dom(
 	if (should_add_css) {
 		body.push(b`
 			function ${add_css}(customStyleTag) {
-				@appendStyleIfNotPresent(customStyleTag || @_document.head, "${component.stylesheet.id}-style", "${styles}");
+				@appendStyleIfNotPresent(customStyleTag, "${component.stylesheet.id}", "${styles}");
 			}
 		`);
 	}

src/runtime/internal/dom.ts

@@ -1,6 +1,10 @@
 import { has_prop } from './utils';
 
-export function appendStyleIfNotPresent(target: Element, styleId: string, styles: string) {
+export function appendStyleIfNotPresent(
+	target: Element = document.head,
+	styleSheetId: string,
+	styles: string,
+	styleId:string = styleSheetId + '-style') {
 	if (!target.querySelector('#' + styleId)) {
 		const style = element('style');
 		style.id = styleId;