diff --git a/src/theme/book.js b/src/theme/book.js
index 83295de9..b22fbe5c 100644
--- a/src/theme/book.js
+++ b/src/theme/book.js
@@ -136,7 +136,15 @@ function playground_text(playground) {
             body: JSON.stringify(params)
         })
         .then(response => response.json())
-        .then(response => result_block.innerText = response.result)
+        .then(response => {
+            if (response.result.trim() === '') {
+                result_block.innerText = "No output";
+                result_block.classList.add("result-no-output");
+            } else {
+                result_block.innerText = response.result;
+                result_block.classList.remove("result-no-output");
+            }
+        })
         .catch(error => result_block.innerText = "Playground Communication: " + error.message);
     }
 
diff --git a/src/theme/css/general.css b/src/theme/css/general.css
index 2cf347f9..63317b39 100644
--- a/src/theme/css/general.css
+++ b/src/theme/css/general.css
@@ -175,3 +175,7 @@ blockquote {
     margin: 5px 0px;
     font-weight: bold;
 }
+
+.result-no-output {
+    font-style: italic;
+}