.glass-circle {
    position: absolute;
    width: 100px;
    height: 100px;
    /* Radiant gradient for surface depth */
    background: radial-gradient(circle at 30% 30%, rgba(255, 255, 255, 0.25), rgba(255, 255, 255, 0.05));

    backdrop-filter: blur(3px);
    -webkit-backdrop-filter: blur(3px);

    /* Thick Glass Edges: Sharp highlight on top/left, diffuse shadow on bottom/right */
    border-top: 1px solid rgba(255, 255, 255, 0.9);
    border-left: 1px solid rgba(255, 255, 255, 0.9);
    border-bottom: 4px solid rgba(255, 255, 255, 0.2);
    border-right: 4px solid rgba(255, 255, 255, 0.2);

    border-radius: 50%;

    /* Inner glow to simulate thickness and refraction */
    box-shadow:
        inset 0 0 20px rgba(255, 255, 255, 0.3),
        /* Internal refraction */
        0 10px 20px rgba(0, 0, 0, 0.1);
    /* External drop shadow */
    z-index: 0;
}

.glass-circle-1 {
    top: 20%;
    left: 10%;
    animation: moveFast1 6s linear infinite;
    /* Fast movement */
}

.glass-circle-2 {
    top: 60%;
    left: 40%;
    width: 140px;
    height: 140px;
    animation: moveFast2 7s linear infinite;
    /* Fast movement, different timing */
}

@keyframes moveFast1 {
    0% {
        transform: translate(0, 0);
    }

    25% {
        transform: translate(30vw, 10vh);
    }

    50% {
        transform: translate(10vw, 30vh);
    }

    75% {
        transform: translate(-10vw, 15vh);
    }

    100% {
        transform: translate(0, 0);
    }
}

@keyframes moveFast2 {
    0% {
        transform: translate(0, 0);
    }

    33% {
        transform: translate(-20vw, -20vh);
    }

    66% {
        transform: translate(20vw, -10vh);
    }

    100% {
        transform: translate(0, 0);
    }
}