I would like to center the elements in my form without moving the text or buttons from being aligned on the left.

So it would look like this:

The bottom square is supposed to be a button.

I want it centered, but the <center> tag moves the text and button so they're centered to the input box.

Here is my code:

<form action="login.php" method="post">
    <div class="aside">
        <div id="center">
            Username:<br>
            <input type="text" name="username"><br>
            Password:<br>
            <input type="password" name="passwor"><br>
            <input type="submit" class="button" name="submit" value="Login"><br><br>
        </div>
    </div>
</form>

and the css:

#center{
    width: 250px;
    margin-left: auto;
    margin-right: auto;
    float: center;
}

div.aside {
    margin-left: 15px;
    margin-top: 10px;
    width: 250px;
    background: #f5f5f5;
    border: 1px solid #e9e9e9;
    line-height: 150%;
}

div.aside .button{
    padding:3px;
    width: 50px;
    margin-top: 3px;
    background-color: #00A1E6;
    border: 1px solid #0184BC;
    text-decoration:none;
    color: #ffffff;
    text-align: center;
    -webkit-appearance: none;
}