I just got an Problem with an iframe and an other element:

**CSS:** 

```
body
{
    margin-right: 0px;
}

ul 
{
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: rgb(180, 180, 180);
    min-width: 750px;
    max-width: auto;
    border-top-left-radius: 35%;
    border-bottom-left-radius: 35%;
    position: relative;
    top: -25px;
}

li 
{
    float: left;
}

li a
{
    display: block;
    text-align: center;
    font-size: 25px;
    color: black;
    padding: 20px;
    text-decoration: none;
}

li a:hover 
{
    background-color: black;
    color: white;
}

iframe
{
    position: relative;
    top: -50px;
    z-index: -1;
    width: 1000px;
    height: 500px;
}

```

**HTML:**

```
<ul>
  <li class="leftcorn"><a href="#home">Home</a></li>
  <li><a href="#news">News</a></li>
  <li><a href="#contact">Kontakt</a></li>
  <li class="rightcorn"><a href="#about">Über uns</a></li>
</ul>
<iframe src="iframe.html"></iframe>

```

[![This is the Website](https://i.stack.imgur.com/Q1ErY.png)](https://i.stack.imgur.com/Q1ErY.png)

I can't press the Button, maybe the li over the iframe is in way 
but how i fix it that it will work?

I just tried everything and I´m not so good, it´s just an Hobbie for me. :)