diff --git a/assets/sass/pages/_single.scss b/assets/sass/pages/_single.scss
index 5f46568..af5f1b5 100644
--- a/assets/sass/pages/_single.scss
+++ b/assets/sass/pages/_single.scss
@@ -461,6 +461,7 @@ pre:not(.chroma) {
 
     &:first-child {
       width: 10px;
+      user-select: none;
 
       pre {
         margin: 0;