diff --git a/bun.lockb b/bun.lockb
index a9d19e1..27d31fe 100755
Binary files a/bun.lockb and b/bun.lockb differ
diff --git a/package.json b/package.json
index 2b102c7..839d3b5 100644
--- a/package.json
+++ b/package.json
@@ -19,6 +19,9 @@
     "@tiptap/core": "^3.14.0",
     "@tiptap/extension-code-block-lowlight": "^3.14.0",
     "@tiptap/extension-color": "^3.14.0",
+    "@tiptap/extension-details": "^3.14.0",
+    "@tiptap/extension-details-content": "^2.26.2",
+    "@tiptap/extension-details-summary": "^2.26.2",
     "@tiptap/extension-image": "^3.14.0",
     "@tiptap/extension-link": "^3.14.0",
     "@tiptap/extension-list-item": "^3.14.0",
diff --git a/src/app.css b/src/app.css
index 841f1e5..db5a622 100644
--- a/src/app.css
+++ b/src/app.css
@@ -810,7 +810,6 @@ a.hover-underline-animation:hover::after {
   pointer-events: none;
 }
 
-/* Task list styles */
 ul[data-type="taskList"] {
   list-style: none;
   padding: 0;
@@ -820,51 +819,80 @@ ul[data-type="taskList"] {
 ul[data-type="taskList"] li {
   display: flex;
   align-items: center;
-  margin: 0.5rem 0;
   gap: 0.5rem;
+  line-height: 0;
 }
 
-ul[data-type="taskList"] li > label {
-  flex: 0 0 auto;
-  user-select: none;
-  display: flex;
-  align-items: center;
-  margin: 0;
-  padding: 0;
-  line-height: 1;
+/* Collapsible section (details/summary) styles */
+details {
+  margin: 1.5rem 0;
+  padding: 1rem;
+  border: 1px solid var(--color-surface2);
+  border-radius: 0.5rem;
+  background-color: var(--color-surface0);
 }
 
-ul[data-type="taskList"] li > div {
-  flex: 1 1 auto;
-}
-
-ul[data-type="taskList"] input[type="checkbox"] {
+summary {
   cursor: pointer;
-  width: 1em;
-  height: 1em;
-  margin: 0;
-  padding: 0;
-  flex-shrink: 0;
-  accent-color: var(--color-blue);
-  transform: none;
-  vertical-align: middle;
-  -webkit-appearance: checkbox;
-  appearance: checkbox;
-  border: 2px solid var(--color-blue);
-  border-radius: 0.15em;
-  background-color: transparent;
+  font-weight: 600;
+  user-select: none;
+  padding: 0.5rem;
+  margin: -1rem -1rem 0 -1rem;
+  background-color: var(--color-surface1);
+  border-radius: 0.5rem 0.5rem 0 0;
+  transition: background-color 0.2s;
+  list-style: none;
 }
 
-ul[data-type="taskList"] input[type="checkbox"]:checked {
-  background-color: var(--color-blue);
+summary::-webkit-details-marker {
+  display: none;
 }
 
-ul[data-type="taskList"] li[data-checked="true"] > div {
-  text-decoration: line-through;
-  opacity: 0.6;
+summary::before {
+  content: "▶ ";
+  color: var(--color-blue);
+  display: inline-block;
+  transition: transform 0.2s;
 }
 
-/* Nested task lists */
-ul[data-type="taskList"] ul[data-type="taskList"] {
-  margin: 0.5rem 0 0.5rem 1.5rem;
+details[open] summary::before {
+  transform: rotate(90deg);
+  color: var(--color-green);
+}
+
+summary:hover {
+  background-color: var(--color-surface2);
+}
+
+details[open] summary {
+  margin-bottom: 1rem;
+  border-bottom: 1px solid var(--color-surface2);
+  border-radius: 0.5rem 0.5rem 0 0;
+}
+
+/* Content inside details */
+details div[data-type="details-content"] {
+  padding: 0.5rem;
+}
+
+/* Nested details */
+details details {
+  margin: 1rem 0;
+  border-color: var(--color-surface1);
+}
+
+/* Animation */
+details[open] div[data-type="details-content"] {
+  animation: slideDown 0.2s ease-out;
+}
+
+@keyframes slideDown {
+  from {
+    opacity: 0;
+    transform: translateY(-10px);
+  }
+  to {
+    opacity: 1;
+    transform: translateY(0);
+  }
 }
diff --git a/src/components/blog/TextEditor.tsx b/src/components/blog/TextEditor.tsx
index 174e2c0..1a72e0c 100644
--- a/src/components/blog/TextEditor.tsx
+++ b/src/components/blog/TextEditor.tsx
@@ -10,6 +10,9 @@ import { TableHeader } from "@tiptap/extension-table-header";
 import { TableCell } from "@tiptap/extension-table-cell";
 import TaskList from "@tiptap/extension-task-list";
 import TaskItem from "@tiptap/extension-task-item";
+import Details from "@tiptap/extension-details";
+import DetailsSummary from "@tiptap/extension-details-summary";
+import DetailsContent from "@tiptap/extension-details-content";
 import { Node } from "@tiptap/core";
 import { createLowlight, common } from "lowlight";
 import css from "highlight.js/lib/languages/css";
@@ -225,6 +228,9 @@ export default function TextEditor(props: TextEditorProps) {
           class: "task-item"
         }
       }),
+      Details,
+      DetailsSummary,
+      DetailsContent,
       Table.configure({
         resizable: true,
         HTMLAttributes: {
@@ -336,6 +342,38 @@ export default function TextEditor(props: TextEditorProps) {
     }
   };
 
+  const insertCollapsibleSection = () => {
+    const instance = editor();
+    if (!instance) return;
+
+    const title = window.prompt("Section title:", "Click to expand");
+
+    if (title !== null) {
+      instance
+        .chain()
+        .focus()
+        .insertContent({
+          type: "details",
+          content: [
+            {
+              type: "detailsSummary",
+              content: [{ type: "text", text: title }]
+            },
+            {
+              type: "detailsContent",
+              content: [
+                {
+                  type: "paragraph",
+                  content: [{ type: "text", text: "Add your content here..." }]
+                }
+              ]
+            }
+          ]
+        })
+        .run();
+    }
+  };
+
   const insertCodeBlock = (language: string | null) => {
     const instance = editor();
     if (!instance) return;
@@ -1013,6 +1051,14 @@ export default function TextEditor(props: TextEditorProps) {
               >
                 " Quote
               </button>
+              <button
+                type="button"
+                onClick={insertCollapsibleSection}
+                class="hover:bg-surface1 rounded px-2 py-1 text-xs"
+                title="Insert Collapsible Section"
+              >
+                ▼ Details
+              </button>
               <div class="border-surface2 mx-1 border-l"></div>
               <button
                 type="button"