Changing the colour of bullet points in a marketing email

Set the colour on the li itself, that colours the bullet, then wrap the text inside in a span with your normal text colour. So the li gets the brand colour and the span puts the words back to dark grey. Don't bother with ::marker, a lot of email clients ignore it. If you need it pixel-perfect in Outlook as well, build the list as a two-column table with a bullet character in the first cell. Ugly code, but it renders the same everywhere.