.loader {
    /*border: 16px solid #f3f3f3;*/
    border-radius: 50%;
    border-top: 16px solid #3498db;
    width: 140px;
    height: 140px;
    -webkit-animation: spin 2s linear infinite;
    animation: spin 2s linear infinite;
    position: absolute;
    margin-left: 45%;
    margin-top: 15%;
    z-index: 3;
}

.container-loader {
    z-index: 10000;
    background-color: rgba(0, 0, 0, 0.6);
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    visibility:hidden;
}

@-webkit-keyframes spin {
    0% {
        -webkit-transform: rotate(0deg);
    }

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

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

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