.zalo_bg:hover {
    opacity: 0.7;
}


.zalo_bg::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border-radius: 50%;
    animation: circle-fill-anim 2.3s infinite ease-in-out;
}

.zalo_bg::before {
    content: "";
    position: absolute;
    top: -10%;
    left: -10%;
    width: 120%;
    height: 120%;
    border: 1px solid blue;
    border-radius: 50%;
    animation: circle-fill-anim 2.3s infinite ease-in-out;
}