Remove redundant div. Fix css

public/index.html

@@ -26,12 +26,10 @@
       <h3>
         Output
       </h3>
-      <div>
       <div id="output">
         <div id="output-area" class="output-area"></div>
       </div>
     </div>
-    </div>
 
     <script>
 

public/style.css

@@ -1,5 +1,7 @@
 #output-area {
     border-right: 2px solid grey;
+    border-top: 1px solid grey;
+    border-bottom: 1px solid grey;
     width: 30ch;
 }
 
@@ -7,11 +9,11 @@
     outline: none;
 }
 
-#gutter {
-    background-color: rgb(230, 230, 230);
+.gutter-row {
+    background-color: rgb(179, 179, 179);
 }
 
-#output-row {
+.output-row {
     display: flex;
 }