Fix Firefox textarea ligature rendering bug

userChrome.css

/**
 * Get your profile from about:support page.
 * Create ~/.mozilla/firefox/<profile>/chrome directory.
 * Place to ~/.mozilla/firefox/<profile>/chrome/userContent.css file.
 * Run restorecon -R -F ~/.mozilla/firefox/<profile>/chrome on SELinux-enabled distros.
 * Set toolkit.legacyUserProfileCustomizations.stylesheets to true in about:config page.
 * Restart Firefox and it should be working.
 */

@-moz-document domain("www.example.com") {
    textarea {
        font-variant-ligatures: none;
    }
}