KeyFrame animation works in Chrome and Edge but not Firefox - html

Question

Hello I am fairly new to styling and have seen related questions but have not been able to extract my own solution from their answers. I am hoping someone can clue me into why this carousel works as intended on Chrome and Edge but not Firefox. I have tried duplicating nearly all the CSS declarations with -moz prefix without any noticeable impact.
Less importantly, I was only able to animate the nav buttons by targeting their IDs. Originally targeting their class,n-th child had no effect,
This fiddle demonstrates the undesired behavior: https://jsfiddle.net/gharyiey/8h1tLxgo/42/
If you apply color to the "carousel_snapper" div, you can see that it actually is getting animated, but the adjacent div containing the img is not.
Any help is greatly appreciated...
CSS
#keyframes indicate {
0%, 70% {
background-color: #fff;
}
70%, 100% {
background-color: #333;
}
}
#keyframes tonext {
75% {
left: 0%;
}
95% {
left: 100%;
}
98% {
left: 100%;
}
99% {
left: 0%;
}
}
#keyframes tostart {
75% {
left: 0%;
}
95% {
left: -300%;
}
98% {
left: -300%;
}
99% {
left: 0%;
}
}
#keyframes snap {
96% {
scroll-snap-align: center;
}
97% {
scroll-snap-align: none;
}
99% {
scroll-snap-align: none;
}
100% {
scroll-snap-align: center;
}
}
* {
box-sizing: border-box;
scrollbar-color: transparent transparent; /*thumb and track color*/
scrollbar-width: 0px;
}
*::-webkit-scrollbar {
width: 0;
}
*::-webkit-scrollbar-track {
background: transparent;
}
*::-webkit-scrollbar-thumb {
background: transparent;
border: none;
}
.carousel > ol, li {
list-style: none;
margin: 0;
padding: 0;
}
.carousel {
position: relative;
filter: drop-shadow(0 0 10px #0003);
perspective: 100px;
}
.carousel__viewport {
position: relative;
top: 0;
right: 0;
bottom: 0;
left: 0;
display: flex;
overflow-x: scroll;
scroll-behavior: smooth;
scroll-snap-type: x mandatory;
}
.carousel__slide {
position: relative;
flex: 0 0 100%;
}
.carousel__slide::before {
position: absolute;
top: 50%;
left: 50%;
transform: translate3d(-50%, -40%, 70px);
color: #fff;
font-size: 2em;
}
.carousel__snapper {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
scroll-snap-align: center;
/*background-color: greenyellow; <-- UNCOMMENT TO SEE ANIMATED DIV*/
}
#media (hover: hover) {
.carousel__snapper {
animation-name: snap, tonext;
animation-timing-function: ease;
animation-duration: 4100ms;
animation-iteration-count: infinite;
}
#nav1 {
animation: indicate 12300ms infinite -1000ms;
}
#nav2 {
animation: indicate 12300ms infinite 3100ms;
}
#nav3 {
animation: indicate 12300ms infinite 7200ms;
}
.carousel__slide:last-child .carousel__snapper {
animation-name: tostart, snap;
}
}
.carousel:hover .carousel__snapper,
.carousel:focus-within .carousel__snapper {
animation-play-state: paused;
}
.carousel:hover #nav1,
.carousel:focus-within #nav1 {
animation-play-state: paused;
}
.carousel:hover #nav2,
.carousel:focus-within #nav2 {
animation-play-state: paused;
}
.carousel:hover #nav3,
.carousel:focus-within #nav3 {
animation-play-state: paused;
}
.carousel__navigation {
position: absolute;
right: 0;
bottom: 0;
left: 0;
text-align: center;
}
.carousel__navigation-list,
.carousel__navigation-item {
display: inline-block;
}
.carousel__navigation-button {
display: inline-block;
width: 1.5rem;
height: 1.5rem;
background-color: #333;
background-clip: content-box;
border: 0.25rem solid transparent;
border-radius: 50%;
font-size: 0;
transition: transform 0.1s;
}
.dummy_img {
height:290px;
width:640px;
display: block;
margin-left: auto;
margin-right: auto;
}
.img_text {
text-align: center;
vertical-align: middle;
line-height: 290px;
}
HTML
<h1 style="text-align:center">PURE CSS/HTML CAROUSEL WITH ANIMATED NAV</h1>
<section class="carousel" aria-label="Gallery">
<ol class="carousel__viewport">
<li id="carousel__slide1" tabindex="0" class="carousel__slide">
<div class="carousel__snapper"></div>
<div class="dummy_img">
<h1 class="img_text">IMAGE 1</h1>
<!--<a href="">
<img src="img1.jpg" alt="alt_tag_1">
</a>-->
</div>
</li>
<li id="carousel__slide2" tabindex="0" class="carousel__slide">
<div class="carousel__snapper"></div>
<div class="dummy_img">
<h1 class="img_text">IMAGE 2</h1>
<!--<a href="">
<img src="img2.jpg" alt="alt_tag_2">
</a>-->
</div>
</li>
<li id="carousel__slide3" tabindex="0" class="carousel__slide">
<div class="carousel__snapper"></div>
<div class="dummy_img">
<h1 class="img_text">IMAGE 3</h1>
<!--<a href="">
<img src="img3.jpg" alt="alt_tag_3">
</a>-->
</div>
</li>
</ol>
<aside class="carousel__navigation">
<ol class="carousel__navigation-list">
<li class="carousel__navigation-item">
Go to slide 1
</li>
<li class="carousel__navigation-item">
Go to slide 2
</li>
<li class="carousel__navigation-item">
Go to slide 3
</li>
</ol>
</aside>
</section>