Function bubble_colors 

pub fn bubble_colors(
    theme: &Theme,
    role: ConversationRole,
) -> (AlphaColor<Srgb>, AlphaColor<Srgb>)

The bubble and ink for a line on theme.

The other person’s words sit on the raised tier — an object inside the content ground. Yours sit on a wash of your own colour, strengthened until body ink reads on it, so “mine” is the same mark here as your caret and your selection elsewhere; the ink is measured, never assumed.