Theme checklist

[MichaelHatherly]

The package already has several themes based on ones ported from Pygments as well as a default one based on the official Julia colours. This issue is for tracking the addition of other themes (suggestions/PRs welcome) and general improvements to the current collection (which is definitely needed in some of them).

[AzamatB]

I would like to suggest adding support for Mariana theme:

[lazarusA]

Any pointers on how to get started? I would like to add a new theme.

[MichaelHatherly]

Simplest way to get started is to copy one of the existing themes, https://github.com/JuliaDocs/Highlights.jl/blob/master/src/themes/github.jl for example, and then change it's name and style values until it suits what you want. The current set of themes was ported from pygments from what I recall so they generally follow it's naming conventions.