public/fun/button/style.css

body {
    margin: 0;
    padding: 0;
}

.container{
    margin-left: 0;
}

button {
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    z-index: 1;
    display: block;
    height: 20%;
    width: 50%;
    margin: auto;
    padding: 0;
    font: 300 2em/1em 'Courier New', Courier, monospace;
    border: 0;
    background: transparent;
    color: white;
    cursor: pointer;
    text-align: center;
    text-transform: uppercase;
    letter-spacing: 3px;
    word-spacing: 5px;
    text-shadow: 0px 1px 2px rgba(0, 0, 0, 0.5);
    outline: none;
}

button.click {
    -webkit-animation: color 900ms linear;
    animation: color 900ms linear;
}

@-webkit-keyframes color {

    0%,
    20%,
    35%,
    55% {
        color: #19569A;
    }

    10%,
    30%,
    40%,
    70% {
        color: white;
    }
}

@keyframes color {

    0%,
    20%,
    35%,
    55% {
        color: #19569A;
    }

    10%,
    30%,
    40%,
    70% {
        color: white;
    }
}