.hourglass {
    animation: flip 10s ease-in-out infinite;
    border-bottom: solid 1vmin #630;
    border-top: solid 1vmin #630;
    left: 50%;
    margin-left: -6vmin;
    margin-top: -11vmin;
    padding: 0 1vmin;
    position: fixed;
    top: 50%;
}

    .hourglass .top, .hourglass .bottom {
        background-color: #def;
        box-shadow: 0 0 1vmin 1vmin #bcd inset;
        height: 10vmin;
        overflow: hidden;
        position: relative;
        width: 10vmin;
    }

    .hourglass .top {
        border-radius: 0 0 50% 50%;
    }

        .hourglass .top:before {
            animation: top 10s linear infinite;
            background-color: #fc6;
            border-radius: 50%;
            content: "";
            display: block;
            height: 10vmin;
            left: 0;
            position: absolute;
            top: 0;
            transform: translateY(50%);
            width: 10vmin;
        }

        .hourglass .top:after {
            animation: top-drip 10s linear infinite;
            background-color: #fc6;
            content: "";
            display: block;
            height: 100%;
            left: 45%;
            position: absolute;
            top: 0;
            transform: translateY(100%);
            width: 10%;
        }

    .hourglass .bottom {
        border-radius: 50% 50% 0 0;
    }

        .hourglass .bottom:before {
            animation: bottom 10s linear infinite;
            background-color: #fc6;
            border-radius: 50%;
            content: "";
            display: block;
            height: 10vmin;
            left: 0;
            position: absolute;
            top: 0;
            transform: translateY(100%);
            width: 10vmin;
        }

        .hourglass .bottom:after {
            animation: bottom-drip 10s linear infinite;
            background-color: #fc6;
            content: "";
            display: block;
            height: 100%;
            left: 45%;
            position: absolute;
            top: 0;
            width: 10%;
        }

@keyframes flip {
    0%, 45% {
        transform: rotate(0);
    }

    50%, 95% {
        transform: rotate(180deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

@keyframes bottom {
    0% {
        transform: translateY(100%);
    }

    50% {
        transform: translateY(50%);
    }

    51% {
        transform: translateY(-50%);
    }

    100% {
        transform: translateY(-100%);
    }
}

@keyframes top {
    0% {
        transform: translateY(50%);
    }

    50% {
        transform: translateY(100%);
    }

    51% {
        transform: translateY(-100%);
    }

    100% {
        transform: translateY(-50%);
    }
}

@keyframes bottom-drip {
    0% {
        left: 45%;
        transform: translateY(-100%);
        width: 10%;
    }

    5% {
        transform: translateY(0);
    }

    45%, 100% {
        left: 50%;
        transform: translateY(0);
        width: 0;
    }
}

@keyframes top-drip {
    0%, 50% {
        left: 45%;
        transform: translateY(100%);
        width: 10%;
    }

    55% {
        left: 45%;
        transform: translateY(0);
        width: 10%;
    }

    100% {
        left: 50%;
        transform: translateY(0);
        width: 0;
    }
}