* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body {
    background-color: #191919;
    color: rgb(255, 255, 255);
    width: 100vw;
    height: 100vh;
    display: grid;
    justify-content: center;
    align-items: center;
    overflow-y: hidden;
    overflow-x: hidden;
}
@function create-stars() {
    $result: '';
    @for $i from 1 through 100 {
        $result: $result + (random(200) - 100) + 'vw ' + (random(200) - 100) + 'vh ' + '0.75px 0.75px ' + rgb(255, 255, 255) ;
        @if $i < 100 { $result: $result + ','; }
    }
    @return unquote($result);
    
}
@mixin place-stars {
    position: absolute;
    left: 50%;
    top: 50%;
    width: 3px;
    height: 3px;
    border-radius: 100%;
    box-shadow: create-stars();
    filter: drop-shadow(0 0 10px white);
}
.stars {
    position: fixed;
    width: 100%;
    height: 100%;
    .cluster__1 {
        @include place-stars;
        animation: star-movement 9s cubic-bezier(0.75, 0, 1, 0.45) infinite;
    }
    .cluster__2 {
        @include place-stars;
        animation: star-movement 9s - 3s cubic-bezier(0.75, 0, 1, 0.45) infinite;
    }
    .cluster__3 {
        @include place-stars;
        animation: star-movement 9s - 5s cubic-bezier(0.75, 0, 1, 0.45) infinite;
    }
}
@keyframes star-movement {
    0% {
        transform: scale(0.5);
        opacity: 0;
    }
    20% { opacity: 1; }
    100% {
        transform: scale(2);
        opacity: 0;
    }
}