<!DOCTYPE html>
<html>
    <head>
        <title>Hello world!</title>
        <meta charset="utf-8">
        <link rel="stylesheet" type="text/css" href="stylesheets/main.css" />

        <!-- build:js javascripts/main.js -->
        <script type="text/javascript" src="javascripts/main.js"></script>
        <!-- endbuild -->
    </head>
    <body>
        <h1>Hello world!</h1>
    </body>
</html>

<!DOCTYPE html>
<html lang="en">
    <head>
        <title>Hello world!</title>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
        <link rel="stylesheet" type="text/css" href="stylesheets/main.css" />

        <!-- build:js javascripts/main.js -->
        <script type="text/javascript" src="javascripts/main.js"></script>
        <!-- endbuild -->
    </head>
    <body>
        <h1>Hello world!</h1>
    </body>
</html>

Add mobile first related mate by default.
feat: Add mobile first related mate by default.
