I broke the stylesheet cache any browsers may be holding.
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title><?php wp_title(); ?></title>
<!-- <link rel="shortcut icon" href="<?php echo get_template_directory_uri(); ?>/favicon.ico"> -->
- <link rel="stylesheet" href="<?php echo get_stylesheet_directory_uri() ; ?>/css/app.css?v=1.0">
+ <link rel="stylesheet" href="<?php echo get_stylesheet_directory_uri() ; ?>/css/app.css?v=1.0.0">
<link href="https://fonts.googleapis.com/css?family=Roboto:400,400i,500,700" rel="stylesheet">
<?php wp_head(); ?>
</head>