Flexbox margin-right：如果我在一个元素中使用display：none，则自动无效

Question

我想用display:none删除flexbox中的一个项目，我想在margin-right: auto类中将对齐（使用logo）设置为nav类项目。但如果我使用display:none，那么margin-right: auto无法正常工作。怎么了？也许是另一种解决方案而不是display:none？

* {
    margin: 0;
    padding: 0;
}

body {
    background: white;
}

/*
---------------------------
----------Flexbox----------
---------------------------
*/

.container {
    border: 1px solid red;
}

.header {
    display: flex;
    flex-direction: row;
    height: 80px;
}

.menubtn {
    align-self: center;
    margin-left: 20px;
    font-size: 20px;
    margin-right: auto;
}

.logo {
    align-self: center;
    margin-right: 40px;
}

.nav {
    background: #000;
    color: #FFF;
    position: fixed;
    top: 0;
    left: 0;
    height: 100%;
    width: 0%;
    opacity: 0;
    text-align: center;
    overflow-x: hidden;
    list-style: none;
    transition: .5s;
    border: 1px solid blue;
}

.closebtn {
    text-align: left;
    margin-left: 30px;
    margin-top: 30px;
}

.nav-item {
    font-size: 1.8em;
}

.nav-item:nth-child(1n+2) {
    margin-top: 3em;
}



/*
---------------------------
--------Responsive---------
---------------------------
*/

@media (min-width: 640px) {

    .closebtn {
        display: none;
    }

    .menubtn {
        display: none;
    }

    .nav {
        transition: 0;
        background: none;
        color: #000;
        display: flex;
        flex-direction: row;
        align-items: center;
        position: static;
        opacity: 1;
        font-size: 0.8em;
        width: auto;
        margin-right: auto;
    }

    .nav-item:nth-child(1n+2) {
        margin-left: 10px;
    }

    .nav-item:nth-child(1n+2) {
        margin-top: 0;
    }
}

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Mineral Fever</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" href="main.css">
</head>
<body>
    <div class="container">
        <header>
            <div class="header">
                <p class="menubtn" onclick="openNav()">&#9776;</p>
                <nav>
                    <ul id="nav" class="nav">
                        <li class="nav-item closebtn" onclick="closeNav()">&times;</li>
                        <li class="nav-item">Termékek</li>
                        <li class="nav-item">Kapcsolat</li>
                        <li class="nav-item">Szállítás</li>
                    </ul>
                </nav>
                <h1 class="logo">Mineral Fever</h1>
            </div>
        </header>
    </div>
</body>
<script src="main.js"></script>
</html>

Answer 1

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Answer 2

另一答案