diff --git a/src/material/Menu.tsx b/src/material/Menu.tsx
index 9e23f62..04b8d86 100644
--- a/src/material/Menu.tsx
+++ b/src/material/Menu.tsx
@@ -8,6 +8,10 @@ import {
 } from "solid-js";
 import { ANIM_CURVE_STD } from "./theme";
 import "./Menu.css";
+import {
+  animateGrowFromTopRight,
+  animateShrinkToTopRight,
+} from "../platform/anim";
 
 type Props = {
   open?: boolean;
@@ -51,23 +55,7 @@ const Menu: ParentComponent<Props> = (props) => {
             top,
           });
 
-          const overflow = root.style.overflow;
-          root.style.overflow = "hidden";
-          const duration = (rend.height / 1600) * 1000;
-          const easing = ANIM_CURVE_STD;
-          const animation = root.animate(
-            {
-              height: [`${rend.height / 2}px`, `${rend.height}px`],
-            },
-            {
-              duration,
-              easing,
-            },
-          );
-          animation.addEventListener(
-            "finish",
-            () => (root.style.overflow = overflow),
-          );
+          animateGrowFromTopRight(root, { easing: ANIM_CURVE_STD });
         } else {
           openAnimationOrigin = "lt";
           setAnchorPos({ left, top });
@@ -119,19 +107,10 @@ const Menu: ParentComponent<Props> = (props) => {
         root.close();
       });
     } else {
-      const overflow = root.style.overflow;
-      root.style.overflow = "hidden";
-      const animation = root.animate(
-        {
-          height: [`${rend.height}px`, `${rend.height / 2}px`],
-        },
-        {
-          duration: (rend.height / 2 / 1600) * 1000,
-          easing: ANIM_CURVE_STD,
-        },
-      );
+      const animation = animateShrinkToTopRight(root, {
+        easing: ANIM_CURVE_STD,
+      });
       animation.addEventListener("finish", () => {
-        root.style.overflow = overflow;
         root.close();
       });
     }
diff --git a/src/material/theme.css b/src/material/theme.css
index e7cb4d9..09cc746 100644
--- a/src/material/theme.css
+++ b/src/material/theme.css
@@ -117,6 +117,7 @@
   --tutu-shadow-e24: 0px 24px 48px 0px var(--tutu-color-shadow-l2);
 
 
+  /* curves are also hard-coded in theme.ts */
   --tutu-anim-curve-std: cubic-bezier(0.4, 0, 0.2, 1);
   --tutu-anim-curve-deceleration: cubic-bezier(0, 0, 0.2, 1);
   --tutu-anim-curve-aceleration: cubic-bezier(0.4, 0, 1, 1);
diff --git a/src/platform/anim.ts b/src/platform/anim.ts
index 87549d0..3dd0ead 100644
--- a/src/platform/anim.ts
+++ b/src/platform/anim.ts
@@ -53,3 +53,145 @@ export function useHeroSignal(
     return [() => undefined, () => undefined];
   }
 }
+
+export function animateRollOutFromTop(
+  root: HTMLElement,
+  options?: Omit<KeyframeAnimationOptions, "duration">,
+) {
+  const overflow = root.style.overflow;
+  root.style.overflow = "hidden";
+
+  const { height } = root.getBoundingClientRect();
+
+  const opts = Object.assign(
+    {
+      duration: Math.floor((height / 1600) * 1000),
+    },
+    options,
+  );
+
+  const animation = root.animate(
+    {
+      height: ["0px", `${height}px`],
+    },
+    opts,
+  );
+
+  const restore = () => (root.style.overflow = overflow);
+
+  animation.addEventListener("finish", restore);
+  animation.addEventListener("cancel", restore);
+
+  return animation;
+}
+
+
+export function animateRollInFromBottom(
+  root: HTMLElement,
+  options?: Omit<KeyframeAnimationOptions, "duration">,
+) {
+  const overflow = root.style.overflow;
+  root.style.overflow = "hidden";
+
+  const { height } = root.getBoundingClientRect();
+
+  const opts = Object.assign(
+    {
+      duration: Math.floor((height / 1600) * 1000),
+    },
+    options,
+  );
+
+  const animation = root.animate(
+    {
+      height: [`${height}px`, "0px"],
+    },
+    opts,
+  );
+
+  const restore = () => (root.style.overflow = overflow);
+
+  animation.addEventListener("finish", restore);
+  animation.addEventListener("cancel", restore);
+
+  return animation;
+}
+
+export function animateGrowFromTopRight(
+  root: HTMLElement,
+  options?: KeyframeAnimationOptions,
+) {
+  const transformOrigin = root.style.transformOrigin;
+  root.style.transformOrigin = "top right";
+
+  const { width, height } = root.getBoundingClientRect();
+
+  const durationX = Math.floor((height / 1600) * 1000);
+  const durationY = Math.floor((width / 1600) * 1000);
+
+  // finds the offset for the center frame,
+  // it will stops at the (minDuration / maxDuration)%
+  const minDuration = Math.min(durationX, durationY);
+  const maxDuration = Math.max(durationX, durationY);
+
+  const centerOffset = minDuration / maxDuration;
+
+  const keyframes = [
+    { transform: "scaleX(0)", opacity: 0, height: "0px", offset: 0 },
+    {
+      transform: `scaleX(${minDuration === durationX ? "1" : centerOffset})`,
+      height: `${(minDuration === durationY ? 1 : centerOffset) * height}px`,
+      offset: centerOffset,
+      opacity: 1,
+    },
+    { transform: "scaleX(1)", height: `${height}px`, offset: 1 },
+  ];
+
+  const animation = root.animate(
+    keyframes,
+    { ...options, duration: maxDuration },
+  );
+
+  const restore = () => {
+    root.style.transformOrigin = transformOrigin;
+  };
+
+  animation.addEventListener("cancel", restore);
+  animation.addEventListener("finish", restore);
+
+  return animation;
+}
+
+export function animateShrinkToTopRight(
+  root: HTMLElement,
+  options?: KeyframeAnimationOptions,
+) {
+  const overflow = root.style.overflow;
+  root.style.overflow = "hidden";
+  const transformOrigin = root.style.transformOrigin;
+  root.style.transformOrigin = "top right";
+
+  const { width, height } = root.getBoundingClientRect();
+
+  const duration = Math.floor(
+    Math.max((width / 1600) * 1000, (height / 1600) * 1000),
+  );
+
+  const animation = root.animate(
+    {
+      transform: ["scale(1)", "scale(0.5)"],
+      opacity: [1, 0],
+    },
+    { ...options, duration },
+  );
+
+  const restore = () => {
+    root.style.overflow = overflow;
+    root.style.transformOrigin = transformOrigin;
+  };
+
+  animation.addEventListener("cancel", restore);
+  animation.addEventListener("finish", restore);
+
+  return animation;
+}