* {
    box-sizing: border-box;
    margin: 0;
}
.bg {
    min-height: 100svh;
    background-color: #222;
    display: flex;
    justify-content: center;
    align-items: center;
}
.circles {
    width: 900px;
    height: 180px;
    position: relative;
}
.circle {
    height: 100%;
    aspect-ratio: 1;
    border-radius: 50%;
    background-color: #bbb;
    position: absolute;
    top: 0;
    left: 100px;
    opacity: 0;
    scale: 0;
    animation: change 2s linear infinite;
}
@keyframes change {
    18% {
        opacity: 1;
        scale: 0.6;
        left: 0;
    }
    20% {
        opacity: 1;
        scale: 0.6;
        left: 0;
    }
    70% {
        scale: 1.1;
        opacity: 1;
        left: 80%;
    }
    73% {
        scale: 1.1;
        opacity: 1;
        left: 80%;
    }
    100% {
        scale: 0;
        opacity: 0;
        left: 60%;
    }
}
.circle2 {
    animation-delay: 1s;
}

@media screen and (max-width: 1100px) {
    .circles {
        width: 500px;
        height: 120px;
    }
    .circle {
        animation-duration: 1.5s;
    }
    .circle2 {
        animation-delay: 0.75s;
    }
}
@media screen and (max-width: 650px) {
    .circles {
        width: 300px;
        height: 60px;
    }
    .circle {
        animation-duration: 1.2s;
    }
    .circle2 {
        animation-delay: 0.6s;
    }
}