增加了“返回顶部”按钮，同时toc容器y如果overflow，滚动条会视情况生成，不会默认全生成了。

themes/nboat/layout/post.ejs

@@ -26,8 +26,12 @@
     </div>
 </main>
 
-<script>
+<button type="button" class="btn btn-danger btn-floating btn-lg" id="btn-back-to-top">
+    <i class="fas fa-arrow-up"></i>
+</button>
 
+<script>
+    // auto scroll to active toc item
     document.addEventListener('DOMContentLoaded', function () {
         var firstScrollSpyEl = document.querySelector('[data-bs-spy="scroll"]')
         let scroll_timer;
@@ -45,4 +49,32 @@
         });
     });
 
+
+    // back to top button
+    // code from https://mdbootstrap.com/docs/standard/extended/back-to-top/
+    //Get the button
+    let mybutton = document.getElementById("btn-back-to-top");
+
+    // When the user scrolls down 20px from the top of the document, show the button
+    window.onscroll = function () {
+        scrollFunction();
+    };
+
+    function scrollFunction() {
+        if (
+            document.body.scrollTop > 20 ||
+            document.documentElement.scrollTop > 20
+        ) {
+            mybutton.style.display = "block";
+        } else {
+            mybutton.style.display = "none";
+        }
+    }
+    // When the user clicks on the button, scroll to the top of the document
+    mybutton.addEventListener("click", backToTop);
+
+    function backToTop() {
+        document.body.scrollTop = 0;
+        document.documentElement.scrollTop = 0;
+    }
 </script>

themes/nboat/source/css/partial/post.styl

@@ -133,7 +133,14 @@
     height: 80vh
     position sticky
     top 2rem
-    overflow-y: scroll
+    overflow-y: auto
+
+#btn-back-to-top
+    position: fixed;
+    bottom: 20px;
+    right: 20px;
+    display: none;
+
 
 @media (max-width grid-breakpoints-md)
     .post-details