Slide mode: <hr> not rendered as line in certain page zoom ratio in Mozilla Firefox

[brlin-tw]

Refer this slide-mode document: Markdown文件標記語言簡介 - HackMD

In slide mode the page "Line Breaks" and "Paragraphs" the middle horizontal line is not rendered for some reason in 100% page zoom ratio, the line is visible when page zoom ratio is changed.

100%:

90%:

This bug only reproduced in Mozilla Firefox but not Google Chrome, so it's probably a bug in the browser.

[jackycute]

Do you still experiencing this @Lin-Buo-Ren?