When you are not editing Canvas cards (i.e. not clicked into the card and editing), they are rendered; basically the same as Reading view in a note. If you switch to Reading view in a non-Canvas note, you’ll see the div.HyperMD-list-line, div.cm-line CSS isn’t doing anything. Reading view / rendered contexts use different CSS than the editor (Source mode and Live Preview).
In any event, this should be a start. There may be other elements that need adjusting.