Update style.css

resources/style.css

@@ -23,7 +23,7 @@ body, html {
 }
 
 .leftPanel, .rightPanel {
-  width: 50%;
+  flex: 1;
   display: flex;
   flex-direction: column;
 }
@@ -35,6 +35,10 @@ body, html {
   white-space: pre-wrap;
 }
 
+.leftPanel {
+  max-width: 200px;
+}
+
 .leftPanel textArea {
   min-height: 100;
 }