diff --git a/assets/css/syntax.scss b/assets/css/syntax.scss
index 186e3c7..5d0a0ba 100644
--- a/assets/css/syntax.scss
+++ b/assets/css/syntax.scss
@@ -37,6 +37,9 @@
   padding-left: .9em;
   padding-right: 1em;
   text-align: right;
+  user-select: none;
+  -moz-user-select: none;
+  -webkit-user-select: none;
 }
 
 .chroma .hl .lnt {
@@ -141,4 +144,4 @@
 .chroma .hl {
   display: block;
   background-color: var(--code-highlighted-line);
-}
\ No newline at end of file
+}