Underline <a> (links) by default

[Vanerio]

Hi!
I'm using the VS Code extension to apply this theme, and I noticed that links (a elements) are not underlined, like they are by default on GitHub markdown.
I reported this to the extension repo that uses your theme.
You can take a look at the issue here.
Would be nice to hear your opinion!
Thank you!

[jjspace]

Just want to provide a little more context to this.

The default selector for a tags turns text-decoration off for all links.
Github then adds them back using this _{(rather ugly)} selector:

[data-a11y-link-underlines=true] .markdown-body a,
[data-a11y-link-underlines=true] .markdown-body a:hover,
[data-a11y-link-underlines=true] .markdown-body-short a,
[data-a11y-link-underlines=true] .markdown-body-short a:hover,
[data-a11y-link-underlines=true] .commit-desc a,
[data-a11y-link-underlines=true] .commit-desc a:hover,
[data-a11y-link-underlines=true] .Link--inTextBlock,
[data-a11y-link-underlines=true] .Link--inTextBlock:hover,
[data-a11y-link-underlines=true] .TimelineItem-body .Link--secondary,
[data-a11y-link-underlines=true] .TimelineItem-body .Link--secondary:hover,
[data-a11y-link-underlines=true] .TimelineItem-body:not(.timeline-comment-group) .text-normal .Link--primary:not(.text-bold),
[data-a11y-link-underlines=true] .TimelineItem-body:not(.timeline-comment-group) .text-normal .Link--primary:not(.text-bold):hover,
[data-a11y-link-underlines=true] .TimelineItem-body .Details-element .Link,
[data-a11y-link-underlines=true] .TimelineItem-body .Details-element .Link:hover,
[data-a11y-link-underlines=true] .TimelineItem-body .Link--muted time,
[data-a11y-link-underlines=true] .TimelineItem-body .Link--muted time:hover,
[data-a11y-link-underlines=true] .TimelineItem-body .markdown-title,
[data-a11y-link-underlines=true] .TimelineItem-body .markdown-title:hover,
[data-a11y-link-underlines=true] .TimelineBody [class*=timelineAgoLink],
[data-a11y-link-underlines=true] .TimelineBody [class*=timelineAgoLink]:hover,
[data-a11y-link-underlines=true] .TimelineBody .Link--secondary,
[data-a11y-link-underlines=true] .TimelineBody .Link--secondary:hover,
[data-a11y-link-underlines=true] .TimelineItem-body .Link:not(.Link--primary),
[data-a11y-link-underlines=true] .TimelineItem-body .Link:not(.Link--primary):hover,
[data-a11y-link-underlines=true] .Links--underline a,
[data-a11y-link-underlines=true] .Links--underline a:hover,
[data-a11y-link-underlines=true] .repos-list-description a,
[data-a11y-link-underlines=true] .extended-commit-description-container a {
  text-decoration: underline;
  text-underline-offset: .2rem;
}

I assume this is just because it's an optional setting in Github under the Accessibility settings.

This library filters out all selectors that rely on [data-. I think this is still reasonable as many likely don't have an impact on how the actual markdown body is rendered. We may want to just loosen this or include the link style as an exception like we do the theme colors.

generate-github-markdown-css/index.js

Lines 18 to 20 in 776016d

	if (selector.includes('[data-') && !selector.includes('[data-color-mode')) {
	return false;
	}

Also worth thinking about how downstream projects like the VSCode preview will consume this. Do we leave the selector as is an expect consumers to add the data-a11y-link-underlines to rendered html or provide a different selector override for this?