Fixed header h1 alignment and network name

ui/app/app.js

@@ -140,8 +140,9 @@ App.prototype.renderAppBar = function () {
         // metamask name
         h('h1', {
           style: {
-            position: 'relative',
-            left: '9px',
+            position: 'absolute',
+            left: '50%',
+            transform: 'translateX(-50%)',
           },
         }, 'MetaMask'),
 

ui/app/css/index.css

@@ -163,9 +163,6 @@ textarea.twelve-word-phrase {
 }
 
 .network-name {
-  position: absolute;
-  top: 8px;
-  left: 60px;
   width: 5.2em;
   line-height: 9px;
   text-rendering: geometricPrecision;