Split display

index.html

@@ -10,7 +10,11 @@
     <header><h1>Calculator</h1></header>
     <main>
         <div class="calculator">
-            <div class="screen">0</div>
+            <div class="display">
+                <div class="top-screen"></div>
+                <div class="main-screen">0</div>
+            </div>
+            
             <button class="clear all">C</button>
             <button class="clear error">CE</button>
 
@@ -28,7 +32,7 @@
             <button class="num">2</button>
             <button class="num">3</button>
             <button class="operator">-</button>
-            
+
             <button class="num">0</button>
             <button class="num">.</button>
             <button class="equal">=</button>