Currently, the colours defined for highlighting are not sensitive to the theme used by the user.
For example, on GitHub, the colour used is great when the user is in a dark theme, but not so great if the user is using a light theme. Similarly, for GitLab, the light theme user sees beautiful highlights, but dark theme users do not.
We do not want this to be dependent on the GitHub account preferences since people might be using browser extensions for turning their website into a light theme or dark theme.
Currently, the colours defined for highlighting are not sensitive to the theme used by the user. For example, on GitHub, the colour used is great when the user is in a dark theme, but not so great if the user is using a light theme. Similarly, for GitLab, the light theme user sees beautiful highlights, but dark theme users do not.