html & css [display: flex;] 활용

<!DOCTYPE html>
<head>
    <title>Gradient</title>
    <link rel="stylesheet" href="style.css">
</head>
<body>
    <div class="ellipse">
        <div class="quad">
            <div class="box">
                <div class="cube"></div>
            </div>
            <div class="box">
                <div class="cube b"></div>
                <div class="cube b"></div>
            </div>
            <div class="box">
                <div class="cube c"></div>
                <div class="cube c"></div>
                <div class="cube c"></div>
            </div>

        </div>
    </div>
</body>
</html>

body{
    background-color: khaki;
}
.ellipse{
    background-color: salmon;
    width: 700px;
    height: 700px;
    border-radius: 100%;
    border: 5px solid white;
    margin: 0px auto;
    margin-top: 50px;
}
.quad{
    background: linear-gradient(#8a23f1,#2287da,#93ceff);
    width: 480px;
    height: 480px;
    border: 5px solid black;
    margin: 0px auto;
    margin-top: 105px;
}
.box{
    width: 480px;
    height: 160px;
    display: flex;
}
.cube{
    background-color: aquamarine;
    width: 80px;
    height: 80px;
    border: 4px solid white;
    margin: 0px auto;
    margin-top: 37px;
}
.b{
    background-color: #8173ff;
}
.c{
    background-color: rgb(119, 0, 255);
}

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