Keep fixed position image always in center of viewport - html

Question

I'm looking for a way to keep my fixed position images, which are placed in the background of the page via z-index, always in the center.
Right now they are in the center, but when I start scrolling, they don't move down the page and are therefore no longer centered.
I've tried setting the image container to fixed positioning with top and left 50%. I've also tried using 50vh and 50vw, and have tested other vh and vw values.
* { padding: 0; margin: 0; box-sizing: border-box; }
body {
padding: 30px;
}
li.track {
display: block;
font-size: 5rem;
margin-bottom: 15px;
}
li.track:hover {
color: transparent;
-webkit-text-stroke-color: #18181b;
-webkit-text-stroke-width: 3px;
}
li.track:hover .album-art {
display: block;
}
.album-art {
z-index: -10;
position: fixed;
left: 47vw;
top: 12vh;
width: 90%;
height: 50%;
max-height: 450px;
display: none;
opacity: 0.5;
overflow: hidden;
transform: translateX(-50%);
}
.album-art img {
width: 100%;
}
a {
text-decoration: none;
color: inherit;
}
<div class="tracks">
<ol>
<li class="track">
<a href="#" class="nav">
<div class="album-art"><img src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/1774776/michael-nau.jpg"></div>
<p class="track-name">King Princess - 'Cheap Queen'</p>
</a>
</li>
<li class="track">
<a href="#" class="nav">
<div class="album-art"><img src="hhttps://s3-us-west-2.amazonaws.com/s.cdpn.io/1774776/louie-short.jpg"></div>
<p class="track-name">Charly Bliss - 'Capacity'</p>
</a>
</li>
<li class="track">
<a href="#" class="nav">
<div class="album-art"><img src="/https://s3-us-west-2.amazonaws.com/s.cdpn.io/1774776/P4K-Tom-Waits-Jim-Jarmusch_PitchHeader.jpg"></div>
<p class="track-name">Julia Jacklin - 'Good Guy'</p>
</a>
</li>
<li class="track">
<a href="#" class="nav">
<div class="album-art"><img src="/img/kevin-abstract.png"></div>
<p class="track-name">Kevin Abstract - 'Georgia'</p>
</a>
</li>
<li class="track">
<a href="#" class="nav">
<div class="album-art"><img src="/img/okey-dokey.jpg"></div>
<p class="track-name">Okey Dokey - 'Wag Your Tail'</p>
</a>
</li>
<li class="track">
<a href="#" class="nav">
<div class="album-art"><img src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/1774776/fruit-bats.jpg"></div>
<p class="track-name">Devendra Banhart - 'Kantori Ongaku'</p>
</a>
</li>
<li class="track">
<a href="#" class="nav">
<div class="album-art"><img src="/img/michael-nau.jpg"></div>
<p class="track-name">Michael Nau - 'Rides Through The Morning'</p>
</a>
</li>
<li class="track">
<a href="#" class="nav">
<div class="album-art"><img src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/1774776/fruit-bats.jpg"></div>
<p class="track-name">Hop Along - 'Prior Things'</p>
</a>
</li>
<ol>
</div>
I want the images that appear when hovered to always be in the center of the page (scrolled or not).

Answer 1

try this css:
body {
padding: 30px;
}
li.track {
display: block;
font-size: 5rem;
margin-bottom: 15px;
}
li.track:hover {
color: transparent;
-webkit-text-stroke-color: #18181b;
-webkit-text-stroke-width: 3px;
}
li.track:hover .album-art {
display: block;
}
.album-art {
z-index: -10;
position: fixed;
left: 50%;
top: 50%;
width: 90%;
height: 50%;
max-height: 450px;
display: none;
opacity: 0.5;
overflow: hidden;
transform: translate(-50%,-50%);
}
.album-art img {
width: 100%;
}
a {
text-decoration: none;
color: inherit;
}
thank you