diff --git a/src/index.css b/src/index.css
index 23edcd5..d24bfc5 100644
--- a/src/index.css
+++ b/src/index.css
@@ -451,6 +451,27 @@ body {
 
 .line-numbers__line {
   height: 1.5em;
+  display: flex;
+  align-items: flex-start;
+}
+
+.line-measure {
+  position: absolute;
+  top: 0;
+  left: 0;
+  visibility: hidden;
+  pointer-events: none;
+  white-space: pre-wrap;
+  word-break: break-word;
+  overflow-wrap: anywhere;
+  font-family: "SF Mono", "Menlo", "Consolas", monospace;
+  font-size: 0.95rem;
+  line-height: 1.5;
+  padding: 14px;
+}
+
+.line-measure__line {
+  white-space: pre-wrap;
 }
 
 .editor__textarea {