Can't reach some actions by using the keyboard in Indie Hackers site

First of all, thank you Indie Hackers founders and managers (no need to mention by @ ).
But improving the product is crucial, especially based on users' feedback.

Moments ago my mouse ran out of charge and I put it in charge. Then tried to answer a comment. But I couldn't!
I couldn't select the reply button by using the tab key. Also, I found there are other elements that can't be focused without a mouse.

Again thank you for this community!!!