[docs beta] "Scrolling to an element" example does not work on Safari

Checking the beta docs, I noticed that one of the examples was not working. At first it was not working at all, but after I added a style of overflow-x: auto to the <ul> element, then I could see the desired effect after clicking on the buttons. I could later check that the example works as expected (without any changes in Chrome). My first guess is that Safari doesn't scroll because the element has an implicit overflow as visible.

Please note that this issue is also present on the challenge 3, as it basically uses that same principle to scroll the images.

Steps

1. Open https://beta.reactjs.org/learn/manipulating-the-dom-with-refs#example-scrolling-to-an-element on Safari
2. Click on the buttons

まず、React のベータ版ドキュメントの「Scrolling to an element」セクションにある例を Safari で再現し、同じスクロール原理を使用している challenge 3 と比較してください。報告されている overflow の挙動を調査し、手動でスタイルを変更せずにボタンをクリックしたとき、両方の例が期待どおりに動作することを確認してください。