.progress-bar-wrapper {
    width: 300px;
}

.progress-bar-bg {
    display: block;
    width: 100%;
    background-color: #505050;
    border-radius: 5px;
}

.progress-bar-fill {
    display: block;
    height: 10px;
    background-color: #f00;
    border-radius: 5px;
    -webkit-transition: width 500ms ease-in-out;
    transition: width 500ms ease-in-out;
}