I have 2 problems.
1) I want to move the logo image and box to the center. I don't know why it doesn't work... I think I've used everything including align, but it doesn't move. I solved the menus with a flex.
2) I want the borderline of menus and box to be the same size. The overlapping parts have different sizes of lines.
Thank you reading.
<style type="text/css">
.logo {
    display: flex;
    margin: auto;
    padding: 50px;
}
.nav {
    display: flex;   
}
.menu-center {
    display: flex;  
    margin: auto;
}
.menu-item {
    width: 100px;
    height: 30px;
    border: 1px solid gray;
    text-align: center;
    padding: 10px;
    padding-left: 100px;
    padding-right: 100px;
}
a {
    text-decoration: none;
    color: black;
}
.main {
    margin: 0;
    margin-top: 60px; 
}
.box  {
    display: flex; 
    width: 800px;
    height: 500px;
    border: 1px solid gray;
    margin-top: auto;
    text-align: center;
}
    .main_box {
        display: flex;
        width: 750px;
        height: 450px;
        border: 1px solid black;
        padding: 10px;
        margin: auto;
        text-align: center;
    }
   </style>
    <script type="text/javascript" src="js/jquery-1.12.4.js"></script>
    <script type="text/javascript">
    </script>
        </head>
        <body>
            <div class="logo">
                <a href="index.html"><img src="imgs/logo2.png" alt="" /></a>
            </div>
            <div class="nav">
                <div class="menus">
                    <a href="intro.html"><div class="menu-item">About Me</div></a>
                    <div class="menu-item">My Language</div>
                    <div class="menu-item">Photos</div>
                    <div class="menu-item">Login</div>
                </div>
            </div>
            <div class="box">
                <div class="main_box">
                </div>
            </div>
            <div id="footer">
            </div>
        </body>
    </html>
 
     
     
    
