how to get responsive hamburger menu to not push down content - html

Question

I have this responsive hamburger nav that is currently pushing down the content below it. Is there a way to get it to just hover over the content instead? I have tried so many things, nothing that I am doing works but I'm not an expert. Any help is much appreciated! Thanks!
jsfiddle here
<nav class="header">
<input class="menu-btn" type="checkbox" id="menu-btn" />
<label class="menu-icon" for="menu-btn"><span class="navicon"></span></label>
<ul class="menu">
<li>Our Work</li>
<li>About</li>
<li>Careers</li>
<li>Contact</li>
</ul>
</nav>
<figure id="main-img"></figure>
figure#main-img {
width: 100%;
position: relative;
overflow: hidden;
border-top: 1px solid #000000;
border-bottom: 1px solid #000000;
z-index: 10;
height: 200px;
background-color: red;
}
nav.header {
background-color: silver;
width: 100%;
float: left;
overflow: hidden;
}
.table {
display: table;
margin: 0 auto;
}
.header ul {
list-style: none;
position: relative;
float: left;
display: block;
left: 50%;
max-width: 1200px;
margin: 0;
padding: 0;
}
.header ul li {
position: relative;
right: 50%;
/*float: left;
display: inline-block;*/
}
.header li a {
display: block;
padding: 1em;
text-decoration: none;
color: #000000;
}
.header li a:hover {
background-color: #B5B5B5;
}
.header .menu {
clear: both;
max-height: 0;
transition: max-height .2s ease-out;
}
.header .menu-icon {
cursor: pointer;
display: inline-block;
float: right;
padding: 28px 20px;
position: relative;
user-select: none;
}
.header .menu-icon .navicon {
background: #333;
display: block;
height: 2px;
position: relative;
transition: background .2s ease-out;
width: 18px;
}
.header .menu-icon .navicon:before, .header .menu-icon .navicon:after {
background: #333;
content: '';
display: block;
height: 100%;
position: absolute;
transition: all .2s ease-out;
width: 100%;
}
.header .menu-icon .navicon:before {
top: 5px;
}
.header .menu-icon .navicon:after {
top: -5px;
}
.header .menu-btn {
display: none;
}
.header .menu-btn:checked ~ .menu {
max-height: 240px;
}
.header .menu-btn:checked ~ .menu-icon .navicon {
background: transparent;
}
.header .menu-btn:checked ~ .menu-icon .navicon:before {
transform: rotate(-45deg);
}
.header .menu-btn:checked ~ .menu-icon .navicon:after {
transform: rotate(45deg);
}
.header .menu-btn:checked ~ .menu-icon:not(.steps) .navicon:before, .header .menu-btn:checked ~ .menu-icon:not(.steps) .navicon:after {
top: 0;
}
#media only screen and (min-width: 750px) {
.header li {
float: left;
}
.header li a {
padding: 20px 30px;
}
.header .menu {
clear: none;
/*float: right;*/
max-height: none;
}
.header .menu-icon {
display: none;
}
}
#media only screen and (max-width: 750px) {
.header li a {
background-color: Silver;
opacity: 0.9;
}
.header ul li {
border-bottom: 1px solid #000000;
color: #000;
}
.header ul li:first-child {
border-top: 0px solid #000000;
}
.header ul {
width: 100%;
}
}
#media only screen and (max-width: 480px) {
nav.header {
}
}

Answer 1

Code (only the relevant css, the html did not change) from the JSFiddle in case it stops working:
body {
width:100%;
margin:0;
}
figure#main-img {
width: 100%;
position: relative;
float:left;
overflow: hidden;
border-top: 1px solid #000000;
border-bottom: 1px solid #000000;
height: 300px;
background-color: red;
margin:58px 0 0 0;
}
nav.header {
background-color: silver;
opacity: 0.75;
position: absolute;
width: 100%;
top:0;
z-index:10;
float: left;
margin:0;
overflow:hidden;
}
.header .menu-icon {
padding: 28px 20px;
}
here is a JSFiddle you can work with.
nav.header {
background-color: silver;
position: absolute;
width: 100%;
top:0;
z-index:10;
float: left;
margin:0;
overflow:hidden;
}
Here you can see that I set the position to be absolute, set it to the top and then z-index is a larger number than the default.
Hope it helped, Andrew