.loader {
    display: inline-block;
    width: 30px;
    height: 30px;
    border: 4px solid #555555;
    animation: loader 2s infinite ease;
    margin:40px;
}

.loader-inner {
    vertical-align: top;
    display: inline-block;
    width: 100%;
    background-color: #555555;
    animation: loader-inner 2s infinite ease-in;
}

@keyframes loader {
    0% {
        transform: rotate(0deg);
    }

    25% {
        transform: rotate(180deg);
    }

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

    75% {
        transform: rotate(360deg);
    }

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

@keyframes loader-inner {
    0% {
        height: 0%;
    }

    25% {
        height: 0%;
    }

    50% {
        height: 100%;
    }

    75% {
        height: 100%;
    }

    100% {
        height: 0%;
    }
}