I need to center a button in the header element

Question

I need to put the button in the center of the header element but it seems like I am not capable of doing that. How can I do It please?

Here is the HTML code:

<header>
<nav>
  <div class="logo"></div>
  <ul>
  <li><a href="">About</a></li>
  <li><a href="">Products</a></li>
  <li><a href="">Team</a></li>
  <li><a href="">Blog</a></li>
  <li><a href="">Contact</a></li>
  </ul>
</nav>


 <a href="" class="button">Kdo jsme?</a>

</header> 

And here is the CSS code:

header{
background: url(header.jpg) no-repeat center;
background-size: cover;
width: 100%;
height: 700px;
text-align: center;
}

nav{
  width: auto; 
  height: 80px;
  float: top;
}

.logo{
display: block;
float:left;
background: url(logo.png) no-repeat;
height: 64px;
width: 64px;
margin: 70px 130px auto;

}

nav ul{
margin: 0px auto;
margin-right: 100px;
list-style-type: none;
}

nav ul li {
float: right;
padding: 0px 20px;
margin: 0 5px; 
margin-right: 50px;
font-size: 17px;
height: 73px;
line-height: 13em;

}

nav a {
color: #C3C2C4;
text-decoration: none;
font-family: Open Sans;
}

nav a:hover{
color: white;
}

.nadpis{
margin: auto;
color: white;
font-family: Open Sans;
text-align: center;
padding-top: 250px;
}


 .button {
  font-family: Open Sans;
    font-size: 18px;  
    color: white;
    text-align: center;
    border: 2px solid white;
    border-radius: 20px;
    height: 40px;
    width: 200px;
    margin: 0px auto;
    padding-top: 10px; 
  display: block; 
  }

I have already tried to wrap the button into a div element and center the div but It didn't seem to work.

Answer 1

It is in the middle, just change your button class style to this :

    .button {
        font-family: Open Sans;
        font-size: 18px;
        color: #000000;
        text-align: center;
        border: 2px solid #FF0000;
        border-radius: 20px;
        height: 40px;
        width: 200px;
        margin: 0px auto;
        padding-top: 10px;
        display: block;
        margin-top:40px;
    }

NOTE: it is not responsive, good idea to keep that in mind depending on your requirements