Restructure containers for full-width background

Left and right pad the contents.

Author: wimpyprogrammer

demo/index.html

@@ -34,11 +34,13 @@
 	<!-- End Google Tag Manager (noscript) -->
 
 	<nav class="navbar navbar-expand-lg navbar-dark bg-primary">
-		<a class="navbar-brand" href="javascript:void(0)">RegEx Pattern Creator</a>
+		<div class="container">
+			<a class="navbar-brand" href="javascript:void(0)">RegEx Pattern Creator</a>
+		</div>
 	</nav>
 
-	<div class="container">
-		<form class="jumbotron">
+	<div class="jumbotron">
+		<form class="container">
 			<p class="lead">Generate a concise Regular Expression.</p>
 
 			<div class="form-group">
@@ -74,7 +76,9 @@
 				</button>
 			</div>
 		</form>
+	</div>
 
+	<div class="container">
 		<section class="output">
 			<div class="form-group">
 				<label for="output">