body {
    padding: 0;
    margin: 0;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

#challenge27 .pulse {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background-color: #22a7ffd8;
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 10;
    cursor: pointer;
}
#challenge27 .pulse:hover {
    background-color: #22a7ff;
}

#challenge27 .pulse i {
    color: #fff;
    font-size: 30px;

}
#challenge27 .pulse::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    border-radius: 50%;
    border: 1px solid #42b3ff;
    height: 100px;
    width: 100px;
    animation: pulse-call-button 2s infinite linear;
    z-index: 1;
}

#challenge27 .pulse::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    border-radius: 50%;
    border: 1px solid #42b3ff;
    height: 100px;
    width: 100px;
    animation: pulse-call-button 2s infinite linear;
    animation-delay: 3.5s;
    z-index: 1;
}

@keyframes pulse-call-button {
    0% {
        transform: translate(-50%, -50%) scale(1.0);
    }
    20% {
        transform: translate(-50%, -50%) scale(1.4);
    }
    40% {
        transform: translate(-50%, -50%) scale(1.3);
    }
    60% {
        transform: translate(-50%, -50%) scale(1.4);
    }
    80% {
        transform: translate(-50%, -50%) scale(1.2);
    }
    100%{
        transform: translate(-50%, -50%) scale(0);
    }
}