.os_loader {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background-color: #222;
}

.os_loader_content {
    padding-top: 40vh;
    margin: 0px auto;
    width: 320px;
    text-align: center;
    color: #555;
    font-size: 24px;
}

.os_loader_content .progress {
    background: rgba(0,0,0,0.2);
    margin: 5px -10px 5px -10px;
    height: 2px;
    color: #FFF;
}

.os_loader_content .progress-bar {
    background: rgba(255, 255, 255, 0.3);
}