style updates

web/index.html

@@ -3,6 +3,7 @@
   <head>
     <title>Title</title>
     <link rel="stylesheet" href="/assets/style.css" type="text/css">
+    <meta name="viewport" content="initial-scale=1, maximum-scale=1">
   </head>
   <body>
     <div id="main">

web/style.css

@@ -10,6 +10,7 @@ input {
   width: 80%;
   border: 1px solid #ccc;
   padding: 8px;
+  margin-bottom: 1em;
 }
 
 button {
@@ -21,4 +22,5 @@ button {
 #main {
   margin: auto;
   width: 90%;
+  text-align: center;
 }