monospace.properties attribute set monospace.properties Properties of monospaced content Specifies the font name for monospaced output. This property set used to set the font-size as well, but that doesn't work very well when different fonts are used (as they are in titles and paragraphs, for example). If you want to set the font-size in a customization layer, it's probably going to be more appropriate to set font-size-adjust, if your formatter supports it.