Anyhow know how I can go about creating a background animation like this with CSS?
You can create two absolute html elements and align them left and right accordingly. Then you can apply CSS radial gradient on these elements for example: background: radial-gradient(45% 45% at 50% 50%, rgba(77, 230, 219, 0.2) 0%, rgba(77, 230, 219, 0) 100%); Otherwise, you can use pseudo-elements (:after, :before) instead of HTML tags.
Here is a quick sketch of what you can do:
.hero {
height: 100vh;
width: 100vw;
background-color: #000;
position: relative;
}
.hero:after,
.hero:before {
content: '';
background: radial-gradient(45% 45% at 50% 50%, rgba(77, 230, 219, 0.2) 0%, rgba(77, 230, 219, 0) 100%);
display: block;
position: absolute;
}
.hero:before {
left: -100px;
bottom: 0;
width: 300px;
height: 300px;
}
.hero:after{
right: -100px;
top: 0;
width: 300px;
height: 300px;
}
<div class="hero"></div>
To make life easier, you can use CSS Gradient Generators, such as: https://cssgradient.io/