Stick an image button to the right edge of an iframe overlay - html

Question

I have my resume in an iframe div that overlays my portfolio section when a link in my nav is clicked. I have an "X" image for user to click to close overlay, and I want to place it to the right of the resume iframe (ie: it butts up against the outer right edge of the iframe).
I can't seem to figure out how to do this - I tried using various different float, positioning and margin setups but the closest I can get is where the "x" is on the right side but its position moves with the window rescaling. I would like for it instead to "stick" to the right edge of the resume and stay there! Is there a way to do this? Here is my code:
HTML:
<header>
<nav></nav>
</header>
<div id="resume-overlay">
<div id="resume">
<iframe src="resume.html"></iframe>
<img class="button" src="img/x-button.png">
</div>
</div>
<div id="portfolio">
</div>
CSS:
header {
height: 80px;
width: 1600px;
position: fixed;
top: 0px;
z-index: 1;
background-color: white;
margin-left: 100px;
}
#resume-overlay {
display: none;
position: fixed;
z-index: 2;
top: 80px;
width: 100%;
height: 100%;
background-color: rgba(255, 255, 255, .9);
}
.resume {
position: relative;
max-width: 1600px;
}
iframe {
position: absolute;
width: 100%;
height: 100%;
}
.button {
position: absolute;
z-index: 3;
right: 0;
padding-right: 10%;
}
And my jQuery if needed:
$(function() {
$('#overlay').on('click', function() {
$('#resume-overlay').fadeToggle('fast');
});
$(".button").click(function(event) {
event.preventDefault();
history.back(1);
$('#resume-overlay').fadeToggle('fast');
});
});
To illustrate, I want to move that blue X to the right edge of the white box

Answer 1

I'm not sure they type of error you're seeing yet, but your code here:
.button {
position: absolute;
z-index: 3;
right: 0;
padding-right: 10%;
}
Is all I think you need to address, try adding
top: 0;
right: 0;
And remove the padding, work with those values to get the button where you want it, and it shouldn't move from those setting regardless of window size.