Enforce right-alignment for cell in markdown tables

[gnestor]

Fixes jupyterlab/jupyterlab#2151

[takluyver]

I'm wary of adding !important rules because they're hard for anyone else to override. Are we so confident in our opinion of how tables should look that we're willing to more-or-less force it on everyone?

cc @ellisonbg

[gnestor]

@takluyver I suppose not because in jupyterlab/jupyterlab#2151, @tdaff was actually looking to override the jupyterlab default styles for tables. We do want consistency across notebook and lab though and this would enforce that in notebook. I just don't understand why they're rendering differently given that they're both using marked... I suppose that it could be related to version inconsistency:

• lab: "marked": "^0.3.6"
• notebook: "marked": "~0.3"

[takluyver]

I've moved this to 'backlog' so we can get on with 5.1, but left it open in case people want to work out where the inconsistency is coming from and what we can do about it.

[gnestor]

Ya, I've explored the marked repo and there haven't been any changes to the markdown table style for 4 years, so the cause must be a discrepancy in the way marked is used in notebook vs. lab.

[ghost]

Hi gentlemen,

Has this issue been resolved? Do we now get the table content as left-aligned or centrally aligned by default, instead of the right alignment?

Thanks,
Souvik

[gnestor]

I have just updated this PR to prevent marked from adding inline style for table cells. As a result, there will be no need for !important and this will allow users to specify custom styles in custom.css. This makes the table rendering consistent with jupyterlab (right-aligned by default).

@datasouvik If you prefer the previous styles, then you can add the following to your custom.css (located at ~/.jupyter/custom/custom.css on Unix-based systems):

.rendered_html tr, .rendered_html th, .rendered_html td {
  text-align: center;
}
.rendered_html :first-child {
  text-align: left;
}
.rendered_html :last-child {
  text-align: right;
}

[gnestor]

@takluyver Care to review/merge?

[takluyver]

One minor point, otherwise it looks good.

[takluyver]

Do you want to clear away these commented out lines now that the new code is working?

[gnestor]

@takluyver Thanks, merge away!