diff --git a/packages/otion/src/createInstance.test.ts b/packages/otion/src/createInstance.test.ts
index d570bf8..62c3778 100644
--- a/packages/otion/src/createInstance.test.ts
+++ b/packages/otion/src/createInstance.test.ts
@@ -1,11 +1,13 @@
 import { css as CSSData } from "mdn-data";
 
-import { PRECEDENCE_GROUP_COUNT } from "./createInstance";
+import { createInstance, PRECEDENCE_GROUP_COUNT } from "./createInstance";
 import { PRECEDENCES_BY_PSEUDO_CLASS } from "./pseudos";
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 const cssProperties = Object.entries<any>(CSSData.properties);
 
+jest.mock("@emotion/hash", () => () => `1f0cb2`);
+
 test("number of precedence groups is correct", () => {
 	const pseudoClassPrecedenceGroupCount = new Set(
 		PRECEDENCES_BY_PSEUDO_CLASS.values(),
@@ -34,3 +36,20 @@ test("number of precedence groups is correct", () => {
 			conditionalPrecedenceGroupExistenceMultiplier,
 	);
 });
+
+test.each([
+	["single", { margin: "50%" }, "{margin:50%}"],
+	["multiple", { margin: "50%", width: "50%" }, "{margin:50%;width:50%}"],
+])("keyframes works correctly with %s properties", (_, rules, output) => {
+	const defaultInstance = createInstance();
+	const injector = { insert: jest.fn() };
+
+	defaultInstance.setup({ injector });
+
+	defaultInstance.keyframes({ "0%": rules }).toString();
+
+	expect(injector.insert).toHaveBeenCalledWith(
+		`@keyframes _1f0cb2{0%${output}}`,
+		0,
+	);
+});
diff --git a/packages/otion/src/createInstance.ts b/packages/otion/src/createInstance.ts
index de105ec..1d5ea9c 100644
--- a/packages/otion/src/createInstance.ts
+++ b/packages/otion/src/createInstance.ts
@@ -386,10 +386,11 @@ export function createInstance(): OtionInstance {
 
 								if (value != null) {
 									const property = normalizeProperty(key);
-									cssText += serializeDeclarationList(property, value);
+									cssText += `;${serializeDeclarationList(property, value)}`;
 								}
 							}
 
+							cssText = cssText.replace("{;", "{");
 							cssText += "}";
 						}