If you look at the link I provided, it shows various ways of coding a black star, including an HTML entity. I can only suggest you try them to see which, if any, produce the result you want.
★ should display ★ (without the need to use brackets of any kind).
In an older version of HTML, you could use "smaller" to reduce font size (long obsolete). Whether or not that would work for you, I've no idea.
The hex codes you are using for colours are just that - colours.