flag.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Flags in Pure CSS</title>
    <link href="css/flag.css" rel="stylesheet">
</head>
<body>
    <div id="blue">
        <div id="left" class="red"></div>
        <div id="right"class="red"></div>
        <div id="up"class="red"></div>
        <div id="down"class="red"></div>
        <div class="white"></div>
        <div id="cover"></div>
    </div>
</body>
</html>