html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css">
<style>
html {
height: 100%;
}
body {
height: 100%;
margin: 0;
}
.container {
height: 100%;
background-image: url('img/sky.jpg');
background-color:rgba(255,255,255,0.8);
background-blend-mode:lighten;
background-repeat: no-repeat;
background-position: center 20px;
}
</style>
</head>
<body>
<div class="container col-md-12">
<h1 class="text-center">背景画像テスト</h1>
<p>テキストが入りますテキストが入ります</p>
</div>
<script>
</script>
</body>
</html>
なるほど
