feat: use the first paragraph as the excerpt if description is not set

src/components/PostCard.astro

@@ -48,8 +48,8 @@ const { remarkPluginFrontmatter } = await entry.render();
         <PostMetadata published={published} tags={tags} category={category} hideTagsForMobile={true} class="mb-4"></PostMetadata>
 
         <!-- description -->
-        <div class="transition text-75 mb-3.5 pr-4">
-            { description }
+        <div class:list={["transition text-75 mb-3.5 pr-4", {"line-clamp-2 md:line-clamp-1": !description}]}>
+            { description || remarkPluginFrontmatter.excerpt }
         </div>
 
         <!-- word count and read time  -->

src/plugins/remark-excerpt.js

@@ -0,0 +1,16 @@
+import { toString } from 'mdast-util-to-string'
+
+/* Use the post's first paragraph as the excerpt */
+export function remarkExcerpt() {
+    return (tree, { data }) => {
+        let excerpt = '';
+        for (let node of tree.children) {
+            if (node.type !== 'paragraph') {
+                continue
+            }
+            excerpt = toString(node)
+            break
+        }
+        data.astro.frontmatter.excerpt = excerpt
+    };
+}