Fix: Reduce input text area width to fit grid boxes

Modified style.css to set the input width to 100% to prevent overflow.

style.css

@@ -7,7 +7,7 @@
 }
 
 .calculator input {
-    width: auto;
+    width: 100%;
     padding: 20px;
     font-size: 24px;
     border: none;