Add collapse behavior to nested lists in TMiR table of contents (#355)

* Add collapsible nested items to transcript table of contents

Implements individually collapsible list items for nested sections in
transcript TOCs using native HTML details/summary elements. Each parent
item with children can now be collapsed independently without JavaScript.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* Change summary element to display: block

Updates TOC summary elements to use block display instead of inline
for better layout control while keeping the arrow inline.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* Improve rendering of table of contents for TMiR

---------

Co-authored-by: Claude <[email protected]>

Author: vcarl

src/components/Layout/LayoutStyles.js

@@ -57,15 +57,9 @@ const standardLayout = css`
   }
 
   details {
-    margin-bottom: 1rem;
-
     & summary {
       cursor: pointer;
     }
-
-    &:last-of-type {
-      margin-bottom: 2rem;
-    }
   }
 
   blockquote {

src/components/Layout/MainStyles.js

@@ -62,14 +62,11 @@ html body {
   }
 
   ul, ol {
-    padding-left: 3rem;
-
+    padding-left: 1.5rem;
+    padding-top: 0.5rem;
     li {
       margin-bottom: 0.5rem;
     }
-    li:first-of-type {
-      margin-top: 0.5rem;
-    }
   }
 
   h1, h2, h3, h4, h5, h6 {
@@ -136,5 +133,9 @@ html body {
       text-decoration: underline;
     }
   }
+
+  summary::before {
+    margin-right: 0.5rem;
+  }
 }
 `;

src/components/Layout/MarkdownStyles.js

@@ -29,10 +29,37 @@ export const MarkdownStyles = createGlobalStyle`
       text-decoration: underline;
     }
   }
+  code {
+    font-size: 80%;
+  }
   a, code, strong {
     white-space: pre-wrap;
     word-break: break-word;
     word-wrap: break-word;
   }
+  li > details {
+    display: block;
+  }
+  summary {
+    cursor: pointer;
+    user-select: none;
+    list-style: none;
+    display: block;
+    &::marker,
+    &::-webkit-details-marker {
+      display: none;
+    }
+    &::before {
+      content: '▶ ';
+      display: inline;
+      font-size: 0.75em;
+      transition: transform 0.15s ease;
+      display: inline-block;
+      width: 1em;
+    }
+  }
+  details[open] > summary::before {
+    transform: rotate(90deg);
+  }
 }
 `;

src/helpers/rehypeWrapFirstList.ts

@@ -0,0 +1,57 @@
+import { visit } from "unist-util-visit";
+import type { Root, Element, ElementContent } from "hast";
+
+/**
+ * Rehype plugin that makes nested list items individually collapsible.
+ * For each <li> that contains a nested <ul>, wraps the content in
+ * <details><summary> to enable collapse/expand functionality.
+ */
+export default function rehypeWrapFirstList() {
+  return (tree: Root) => {
+    visit(tree, "element", (node) => {
+      // Only process <li> elements
+      if (node.tagName !== "li") {
+        return;
+      }
+
+      // Check if this <li> has a nested <ul> child
+      const nestedUlIndex = node.children.findIndex(
+        (child): child is Element =>
+          child.type === "element" && child.tagName === "ul",
+      );
+
+      // If no nested <ul>, nothing to do
+      if (nestedUlIndex === -1) {
+        return;
+      }
+
+      // Split children into summary content (before ul) and nested ul
+      const summaryContent = node.children.slice(0, nestedUlIndex);
+      const nestedUl = node.children[nestedUlIndex] as Element;
+
+      // Only wrap if there's content to put in the summary
+      if (summaryContent.length === 0) {
+        return;
+      }
+
+      // Create the summary element with the content before the nested ul
+      const summary: Element = {
+        type: "element",
+        tagName: "summary",
+        properties: {},
+        children: summaryContent as ElementContent[],
+      };
+
+      // Create the details element
+      const details: Element = {
+        type: "element",
+        tagName: "details",
+        properties: { open: true }, // Open by default
+        children: [summary, nestedUl],
+      };
+
+      // Replace the <li>'s children with just the details element
+      node.children = [details];
+    });
+  };
+}

src/helpers/retrieveMdPages.ts

@@ -10,6 +10,7 @@ import rehypeStringify from "rehype-stringify";
 import rehypeSlug from "rehype-slug";
 import remarkHeadings, { hasHeadingsData } from "@vcarl/remark-headings";
 import { toString } from "mdast-util-to-string";
+import rehypeWrapFirstList from "./rehypeWrapFirstList";
 
 const loadMd = async (path: string) => {
   const fullPath = join(process.cwd(), `${path}.md`);
@@ -39,8 +40,26 @@ const remarkHtmlProcessor = unified()
   .use(rehypeSlug)
   .use(rehypeStringify, { allowDangerousHtml: true });
 
-export const processMd = (mdSource: string) => {
-  const vfile = remarkHtmlProcessor.processSync(mdSource);
+export interface ProcessMdOptions {
+  wrapFirstList?: boolean;
+}
+
+export const processMd = (mdSource: string, options?: ProcessMdOptions) => {
+  let processor = remarkHtmlProcessor;
+
+  // If wrapFirstList is enabled, add the rehype plugin
+  if (options?.wrapFirstList) {
+    processor = unified()
+      .use(parse)
+      .use(remarkGfm)
+      .use(remarkHeadings as ReturnType<ReturnType<typeof unified>["use"]>)
+      .use(remarkRehype, { allowDangerousHtml: true })
+      .use(rehypeSlug)
+      .use(rehypeWrapFirstList)
+      .use(rehypeStringify, { allowDangerousHtml: true });
+  }
+
+  const vfile = processor.processSync(mdSource);
   if (hasHeadingsData(vfile.data)) {
     return { html: vfile.toString(), headings: vfile.data.headings };
   }

src/pages/transcripts/[slug].tsx

@@ -88,7 +88,7 @@ export const getStaticProps = async ({
     props: {
       all,
       ...pick(["title", "date"], doc),
-      html: processMd(doc.content).html,
+      html: processMd(doc.content, { wrapFirstList: true }).html,
       description: processMdPlaintext(doc.description).html,
     },
   };