diff --git a/README.md b/README.md
index 27a6075a..0437ec18 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,8 @@
 JS-Interpreter
 ==============
 
+<img src="./fullWidth.jpg" alt="Full width"/>
+
 A sandboxed JavaScript interpreter in JavaScript.  Execute arbitrary JavaScript
 code line by line in isolation and safety.
 
diff --git a/fullWidth.jpg b/fullWidth.jpg
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diff --git a/index.css b/index.css
new file mode 100644
index 00000000..fc9e6a1e
--- /dev/null
+++ b/index.css
@@ -0,0 +1,60 @@
+* {
+  margin: 0;
+  padding: 0;
+  box-sizing: border-box;
+}
+.container {
+  max-width: 1200px;
+  width: 100%;
+  padding-right: 15px;
+  padding-left: 15px;
+  margin: 2rem auto;
+}
+
+.container h1 {
+  margin: 1rem 0;
+  font-weight: 600;
+  font-size: x-large;
+  color: #324146;
+}
+
+.container .description {
+  margin-bottom: .8rem;
+  font-weight: 100;
+  color: #355056;
+}
+
+textarea {
+  background-color: #355056;
+  border: 1px solid #324146;
+  border-radius: .3rem;
+  color: #ffffff;
+  padding: .5rem 0;
+  margin-bottom: .5rem;
+}
+
+button {
+  display: inline-block;
+  font-weight: 400;
+  text-align: center;
+  white-space: nowrap;
+  vertical-align: middle;
+  -webkit-user-select: none;
+  -moz-user-select: none;
+  -ms-user-select: none;
+  user-select: none;
+  border: 1px solid transparent;
+  padding: 0.375rem 0.75rem;
+  font-size: 1rem;
+  line-height: 1.5;
+  border-radius: 0.25rem;
+  transition: color 0.15s ease-in-out, background-color 0.15s ease-in-out, border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
+  cursor: pointer;
+  margin-bottom: .5rem;
+}
+
+button:hover {
+  color: #fff;
+  background-color: #324146;
+  border-color: #324146;
+}
\ No newline at end of file
diff --git a/index.html b/index.html
index b1ef32d4..ebf7f2e8 100644
--- a/index.html
+++ b/index.html
@@ -3,8 +3,12 @@
 <head>
   <meta charset="utf-8">
   <title>JS-Interpreter Demo</title>
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <link href="demos/style.css" rel="stylesheet" type="text/css">
 
+  <!-- custom css -->
+  <link rel="stylesheet" href="index.css">
+
   <script>
     // Depending on the URL argument, test the compressed or uncompressed version.
     var compressed = (document.location.search == '?compressed');
@@ -82,43 +86,44 @@
   </script>
 </head>
 <body>
-  <h1>JS-Interpreter Demo</h1>
-
-  <p>Enter JavaScript code below, then click <em>Parse</em>.  To execute, either
-  click <em>Step</em> repeatedly, or click <em>Run</em> once.
-  Open your browser's console for errors.</p>
-  <p><textarea id="code">
-var result = [];
-function fibonacci(n, output) {
-  var a = 1, b = 1, sum;
-  for (var i = 0; i &lt; n; i++) {
-    output.push(a);
-    sum = a + b;
-    a = b;
-    b = sum;
-  }
-}
-fibonacci(16, result);
-alert(result.join(', '));
-</textarea><br>
-  <button onclick="parseButton()">Parse</button>
-  <button onclick="stepButton()" id="stepButton" disabled="disabled">Step</button>
-  <button onclick="runButton()" id="runButton" disabled="disabled">Run</button>
-  </p>
-
-  <p><small>
-  <script>
-    if (compressed) {
-      document.write('[ Running compressed bundle.  Switch to <A HREF="?uncompressed">raw sources</A>. ]');
-    } else {
-      document.write('[ Running raw sources.  Switch to <A HREF="?compressed">compressed bundle</A>. ]');
+  <div class="container">
+    <h1>JS-Interpreter Demo</h1>
+    <p class="description">Enter JavaScript code below, then click <em>Parse</em>.  To execute, either
+    click <em>Step</em> repeatedly, or click <em>Run</em> once.
+    <br> Open your browser's console for errors.</p>
+    <p><textarea id="code">
+  var result = [];
+  function fibonacci(n, output) {
+    var a = 1, b = 1, sum;
+    for (var i = 0; i &lt; n; i++) {
+      output.push(a);
+      sum = a + b;
+      a = b;
+      b = sum;
     }
-    disable('disabled');
-  </script>
-  </small></p>
-
-  <p>Read the <a href="docs.html">JS-Interpreter documentation</a>.</p>
-  <p>Get the <a href="https://github.com/NeilFraser/JS-Interpreter">source code</a>.</p>
-
+  }
+  fibonacci(16, result);
+  alert(result.join(', '));
+  </textarea><br>
+    <button class="btn" onclick="parseButton()">Parse</button>
+    <button onclick="stepButton()" id="stepButton" disabled="disabled">Step</button>
+    <button onclick="runButton()" id="runButton" disabled="disabled">Run</button>
+    </p>
+  
+    <p><small>
+    <script>
+      if (compressed) {
+        document.write('[ Running compressed bundle.  Switch to <A HREF="?uncompressed">raw sources</A>. ]');
+      } else {
+        document.write('[ Running raw sources.  Switch to <A HREF="?compressed">compressed bundle</A>. ]');
+      }
+      disable('disabled');
+    </script>
+    </small></p>
+  
+    <p>Read the <a href="docs.html">JS-Interpreter documentation</a>.</p>
+    <p>Get the <a href="https://github.com/NeilFraser/JS-Interpreter">source code</a>.</p>
+  
+  </div>
 </body>
 </html>
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