OptionalcolorOverride fill color. When set, used for all runs (italic and bold).
OptionalfamilyFont-family spec (e.g. '"Iowan Old Style", Georgia, serif'). Defaults to sans-serif.
OptionallineMultiplier applied to font size for line height. Default 1.3.
OptionalweightNumeric weight applied to non-bold runs. Bold runs always use bold. Default normal.
Font styling options threaded through
createMarkdownRenderer.