.loader {
    position: absolute;
    top: 0px;
    bottom: 0px;
    left: 0px;
    right: 0px;
    margin: auto;
    width: 175px;
    height: 100px;
}
    .loader span {
        display: block;
        background: #ccc;
        width: 7px;
        height: 10%;
        border-radius: 14px;
        margin-right: 5px;
        float: left;
        margin-top: 25%;
    }

        .loader span:last-child {
            margin-right: 0px;
        }

        .loader span:nth-child(1) {
            animation: load 2.5s 1.4s infinite linear;
        }

        .loader span:nth-child(2) {
            animation: load 2.5s 1.2s infinite linear;
        }

        .loader span:nth-child(3) {
            animation: load 2.5s 1s infinite linear;
        }

        .loader span:nth-child(4) {
            animation: load 2.5s 0.8s infinite linear;
        }

        .loader span:nth-child(5) {
            animation: load 2.5s 0.6s infinite linear;
        }

        .loader span:nth-child(6) {
            animation: load 2.5s 0.4s infinite linear;
        }

        .loader span:nth-child(7) {
            animation: load 2.5s 0.2s infinite linear;
        }

        .loader span:nth-child(8) {
            animation: load 2.5s 0s infinite linear;
        }

        .loader span:nth-child(9) {
            animation: load 2.5s 0.2s infinite linear;
        }

        .loader span:nth-child(10) {
            animation: load 2.5s 0.4s infinite linear;
        }

        .loader span:nth-child(11) {
            animation: load 2.5s 0.6s infinite linear;
        }

        .loader span:nth-child(12) {
            animation: load 2.5s 0.8s infinite linear;
        }

        .loader span:nth-child(13) {
            animation: load 2.5s 1s infinite linear;
        }

        .loader span:nth-child(14) {
            animation: load 2.5s 1.2s infinite linear;
        }

        .loader span:nth-child(15) {
            animation: load 2.5s 1.4s infinite linear;
        }

@keyframes load {
    0% {
        background: #ccc;
        margin-top: 25%;
        height: 10%;
    }

    50% {
        background: #444;
        height: 100%;
        margin-top: 0%;
    }

    100% {
        background: #ccc;
        height: 10%;
        margin-top: 25%;
    }
}