For using colors, currently HTML color names or hex colors can be provided, e.g.:

\textcolor{blue}{F=ma} -> $\textcolor{blue}{F=ma}$
\textcolor{#228B22}{F=ma} -> $\textcolor{#228B22}{F=ma}$

For the latter, it would be great if also alpha, i.e. transparency values could be supported. Typically, these would just be added to the hex color code, e.g. #228B2280
Latex also has the feature to specify transparency for colors like this:

\colorbox{blue!80}{Hello World}