re-wrap with custom-scroll

src/App.css

@@ -7,6 +7,7 @@
 }
 
 .app-root {
+  max-height: calc(100vh - 70px);
   max-width: 900px;
   margin: 0 auto;
   padding-top: 90px;

src/App.tsx

@@ -1,22 +1,25 @@
 import "./App.css";
 import { DemoComp } from "./example/demoComp.tsx";
+import { CustomScroll } from "./customScroll.tsx";
 
 export const App = () => {
   return (
-    <div data-testid="app-root" className="app-root">
-      <div className="demo-title">React-Custom-Scroll Demo page</div>
-      <div className="demo-subtitle">
-        react-custom-scroll lets you design unique scrollbars without
-        compromising on performance. It preserves the browser's native scrolling
-        mechanism, ensuring a smooth, familiar user experience. Its hover design
-        means no content is obscured, offering a consistent look across browsers
-        and operating systems.
+    <CustomScroll>
+      <div data-testid="app-root" className="app-root">
+        <div className="demo-title">React-Custom-Scroll Demo page</div>
+        <div className="demo-subtitle">
+          react-custom-scroll lets you design unique scrollbars without
+          compromising on performance. It preserves the browser's native
+          scrolling mechanism, ensuring a smooth, familiar user experience. Its
+          hover design means no content is obscured, offering a consistent look
+          across browsers and operating systems.
+        </div>
+        <DemoComp demoType="compare-with-native" descriptionSide="left" />
+        <DemoComp demoType="crazy-designer" descriptionSide="right" />
+        <DemoComp demoType="dynamic-content" descriptionSide="left" />
+        <DemoComp demoType="allow-outer-scroll" descriptionSide="right" />
+        <DemoComp demoType="flex" descriptionSide="left" />
       </div>
-      <DemoComp demoType="compare-with-native" descriptionSide="left" />
-      <DemoComp demoType="crazy-designer" descriptionSide="right" />
-      <DemoComp demoType="dynamic-content" descriptionSide="left" />
-      <DemoComp demoType="allow-outer-scroll" descriptionSide="right" />
-      <DemoComp demoType="flex" descriptionSide="left" />
-    </div>
+    </CustomScroll>
   );
 };