body {
    display: block !important;
    background-color: black;
}

#app {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 90vh;
}

#btn {
    border: none;
    background-color: purple;
    color: white;
    padding: 15px 30px;
    font-size: 1.2em;
    position: relative;
    overflow: hidden;
}

#btn .circle {
    position: absolute;
    width: 100px;
    height: 100px;
    transform: translate(-50%, -50%) scale(0);
    border-radius: 50%;
    background-color: white;
    animation: scale .5s ease;
    position: absolute;
}

@keyframes scale {
    to {
        transform: translate(-50%, -50%) scale(3);
        opacity: 0;
    }
}

#point {
    position: absolute;
    width: 10px;
    height:10px;
    background-color: white;
    border-radius: 50%;
    transform: translate(-50%, -50%);
}