diff --git a/session_4/session_4.Rmd b/session_4/session_4.Rmd
index a398a8a514d3041782a055b51c62d9cac1a03fa1..158281fc5047db0aa2e873037600b82912c5720d 100644
--- a/session_4/session_4.Rmd
+++ b/session_4/session_4.Rmd
@@ -41,7 +41,7 @@ As usual you will also need the `tidyverse` library.
 </div>
 
 <details><summary>Solution</summary>
-<p>
+  <p>
 ```{r installP, eval = F}
 install.packages("nycflights13")
 ```
@@ -50,7 +50,7 @@ install.packages("nycflights13")
 library("tidyverse")
 library("nycflights13")
 ```
-</p>
+  </p>
 </details>
  
 ## Data set : nycflights13