body {
    margin: 0;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(black, maroon);
    overflow: hidden;
}

.flame {
    width: 10em;
    height: 12em;
    font-size: 24px;
    position: relative;
}

.flame span {
    position: absolute;
    width: 5em;
    height: 5em;
    background: radial-gradient(
        orangered 20%,
        rgba(255, 69, 0, 0) 70%
    );
    border-radius: 50%;
    bottom: 0;
    left: calc((var(--n) - 1) * 5em / var(--particles));
    mix-blend-mode: screen;
    animation: rise 1s ease-in infinite;
    animation-delay: calc(var(--rnd) * 1s);
    filter: opacity(0);
}

@keyframes rise {
    from {
        transform: translateY(0) scale(1);
        filter: opacity(0);
    }
    
    25% {
        filter: opacity(1);
    }
    
    to {
        transform: translateY(-10em) scale(0);
        filter: opacity(0);
    }
}