ENH: Accessible code highlighting styles

[drammock]

partially addresses #1052

• fix our pygments overrides in __init__
• change theme's pygments defaults to a11y-high-contrast-{dark|light}
• test pygment theme selection
• document what we're doing
• update theme color palette to address text contrast issues -> subsequent PR
• make our CIs test for text contrast issues -> subsequent PR

[trallard]

🎉 this looks great @drammock

[trallard]

Would something like this work for all the Sphinx-based docs? I mean, adding this bit to allow for the dynamic switch?

If so I'd love to add this to the "mini-docs" of accessible-pygments

[drammock]

I think so? I think we adapted it from the Furo theme.

[12rambau]

I confirm that I adapted it from Furo.

[choldgraf]

This change looks good to me - could you add documentation about this in our user guide? I think we could add an Accessibility in this theme section to our Design and style section that could note the various accessibility-minded decisions that have been made here (such as the code blocks, and the default colors).

Also in the name of iteration I'd suggest scoping this PR to just the code blocks, and do the default colors in a follow up.

[12rambau]

Also in the name of iteration I'd suggest scoping this PR to just the code blocks, and do the default colors in a follow up.

@drammock could you then update the comment (avoid closing the issue) and the title ?

[drammock]

This change looks good to me - could you add documentation about this in our user guide? I think we could add an Accessibility in this theme section to our Design and style section

done, though I put it on the "accessibility" page instead (seemed like the right place 😉).

Also in the name of iteration I'd suggest scoping this PR to just the code blocks, and do the default colors in a follow up.

done

could you then update the comment (avoid closing the issue) and the title ?

done, and CIs are happy. This one's ready from my end.

[choldgraf]

Looks great - thanks for this improvement @drammock and to the QS folks for building the accessible pygments repository!

[rsokl]

Is there a configuration option available to revert back to the old light/dark default themes? Or perhaps can the accessibility themes be toggled?

[drammock]

Is there a configuration option available to revert back to the old light/dark default themes? Or perhaps can the accessibility themes be toggled?

to get the old defaults you can specify this in your conf.py file:

html_theme_options = {
    # ...other config vals...
    "pygment_light_style": "tango",
    "pygment_dark_style": "monokai",
}

see https://pydata-sphinx-theme.readthedocs.io/en/stable/user_guide/styling.html#configure-pygments-theme