Fix codemirror gutter offset

src/codemirror/index.css

@@ -62,6 +62,11 @@
 }
 
 
+.CodeMirror-gutter-wrapper {
+  margin-left: calc(-1 * var(--jp-code-padding));
+}
+
+
 /*
   Here is our jupyter theme for CodeMirror syntax highlighting
   This is used in our marked.js syntax highlighting and CodeMirror itself