设置flex:1和marginTop时，flex:1的值没有包含marginTop的值

<!DOCTYPE html>

<head>
    <meta charset="utf-8">
    <title>demo</title>
    <style>
        .container{
            height: 100vh;
            display: flex;
            flex-direction: column;
        }
        .top{
            height: 200px;
            background-color: lightblue;
        }
        .bottom{
            flex: 1;
            margin-top: 16px;
            background-color: lightcoral;
        }
    </style>
</head>

<body>
    <div class="container">
        <div class="top"></div>
        <div class="bottom"></div>
    </div>
</body>

期望正好占一屏幕，实际是出现了滚动条，如何达到预期？

图片.png