diff --git a/static/css/code/syntax-highlight.css b/static/css/code/syntax-highlight.css
index af9df72..9f5f153 100644
--- a/static/css/code/syntax-highlight.css
+++ b/static/css/code/syntax-highlight.css
@@ -154,6 +154,11 @@ CodeFlask mappings
   ); /* Makes the text input cursor visible in dark mode */
 }
 
+.codeflask .codeflask__lines {
+  background: var(--code-background);
+  color: var(--code-token-comment);
+}
+
 .codeflask {
   background: var(--code-background);
   color: var(--code-token-base);
diff --git a/static/index.js b/static/index.js
index 38a5f4e..7f6f181 100644
--- a/static/index.js
+++ b/static/index.js
@@ -77,6 +77,7 @@ function highlightOutput(target, childClassName) {
 const editor = new CodeFlask("#editor-target", {
   language: "gleam",
   defaultTheme: false,
+  lineNumbers: true,
 });
 editor.addLanguage("gleam", prismGrammar);
 editor.updateCode(initialCode);