Solution found:<p>&gt; The comments on FF for Android do not have any additional indentation to suggest they are children.<p>I reinstalled FF on my phone and you&#x27;re right. On my tablet FF behaves like Chrome. Some media queries gone awries or some FF quirk on smaller screens? FF-desktop behaves like the one on the phone when the window is resized to be narrow so it seems to be consistent with itself.<p>HN is using a media query to set the indentation using an empty image and setting its width. Check the &#x2F;news.css file. Each comment is a tr, with 3 td elements. The image is the first one, then the votes arrows and the text. FF arranges those td in vertical, blink keeps them on the same row.<p>Digging into the CSS I realized that it&#x27;s because of the display: block at line 88. If I remove it FF indents the comments. Opera keeps looking good.