css 배경색 변경

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <title>bg</title>
        <style>
        html, body { width: 100%; height: 100%; }
        body { background-color: rgb(67, 190, 249); }
        .depth { width: 80%; height: 80%; }
        .depth_00 { background-color: rgb(67, 170, 249); }
        .depth_01 { background-color: rgb(67, 150, 249); }
        .depth_02 { background-color: rgb(67, 130, 249); }
        </style>
    </head>
    <body>
        <div class="depth depth_00">depth_00
            <div class="depth depth_01">depth_01
                <div class="depth depth_02">depth_02
                </div>
            </div>
        </div>
    </body>
</html>