html, body {
    height: 100%;
    width: 100%;
    overflow: hidden
}

#particles {
    width: 100%;
    height: 100%;
    overflow: hidden;
    position: relative;
}

.intro {
    position: absolute;
    left: 0;
    top: 50%;
    padding: 0 20px;
    width: 100%;
    text-align: center;
}