update

app/util.ts

@@ -1,3 +1,6 @@
+import { type InjectionKey, inject } from 'vue';
+import useDJSSRContext from "@/useDJSSRContext.ts";
+
 export function gid(id: string, doc: (Document | ShadowRoot) | undefined) {
     return ((doc ?? document).getElementById(id));
 }
@@ -37,9 +40,23 @@ export function css(strs: TemplateStringsArray, ...vals: string[]) {
     for (let i = 1; i < strs.length; i++) {
         result += vals[i] + strs[i];
     }
-    const sheet = new CSSStyleSheet();
-    sheet.replaceSync(result);
-    return sheet;
+    return result;
+}
+
+
+export const cssRegistry = Symbol('css-registry') as InjectionKey<Set<string>>;
+export function addCSS(key: string, css: string) {
+    const context = useDJSSRContext();
+    if (context && !context.styles[key]) {
+        context.styles[key] = css;
+    } else {
+        const registry = inject(cssRegistry);
+        if (!registry?.has(key)) {
+            const stylesheet = new CSSStyleSheet();
+            stylesheet.replace(css);
+            document.adoptedStyleSheets.push(stylesheet);
+        }
+    }
 }
 
 /*