No subpixel font rendering in Firefox

[formicant]

Current behaviour

In Firefox, all the text in Hackmd documents is rendered without subpixel antialiasing.

The text is hard to read on non-hi-DPI screens.

Expected behaviour

The text should be rendered as set up in the system.

Notes

It must be something to do with CSS styling. Possibly, semi-transparent backgrounds.

If I apply a user style like this

.CodeMirror-sizer { background: white; }

the code pane starts to render the fonts correctly:

Environment

I use HackMD on:

** Desktop**

• OS:
  • Arch Linux, KDE Plasma, X11
  • Windows 10 Pro 22H2 19045.4651
• Browser: Firefox
• Browser Version: 128.0

In Chromium, everything is rendered correctly, with subpixel antialiasing.