feat(html): scope selector lists in responsive variants

Co-Authored-By: Virgil <virgil@lethean.io>

responsive.go

@@ -80,7 +80,16 @@ func ScopeVariant(name, selector string) string {
 	if selector == "" {
 		return scope
 	}
-	return scope + " " + selector
+
+	parts := strings.Split(selector, ",")
+	for i := range parts {
+		parts[i] = strings.TrimSpace(parts[i])
+		if parts[i] == "" {
+			continue
+		}
+		parts[i] = scope + " " + parts[i]
+	}
+	return strings.Join(parts, ", ")
 }
 
 // responsive.go: Variant adds a named layout variant (e.g., "desktop", "tablet", "mobile").

responsive_test.go

@@ -178,3 +178,11 @@ func TestScopeVariant(t *testing.T) {
 		})
 	}
 }
+
+func TestScopeVariant_MultipleSelectors(t *testing.T) {
+	got := ScopeVariant("desktop", ".nav, .sidebar")
+	want := `[data-variant="desktop"] .nav, [data-variant="desktop"] .sidebar`
+	if got != want {
+		t.Fatalf("ScopeVariant with selector list = %q, want %q", got, want)
+	}
+}