Preloader для сайта — стиль 16

Подробное описание и демонстрацией работы эффекта загрузки под номером №16 для бибилиотеки Bootstrap. Html и CSS код для реализации preloader’a сайта как на изображении.

<div class="container">
    <div class="row">
        <div class="col-md-12">
            <div class="loader">
                <span>L</span>
                <span>O</span>
                <span>A</span>
                <span>D</span>
                <span>I</span>
                <span>N</span>
                <span>G</span>
                <div class="loader-inner">
                    <span></span>
                    <span></span>
                    <span></span>
                    <span></span>
                    <span></span>
                    <span></span>
                    <span></span>
                </div>
            </div>
        </div>
    </div>
</div>

.loader {
    position: relative;
    margin: 40px auto 0;
    width: 350px;
    color: white;
    text-align: center;
    font-size: 250%;
    background: linear-gradient(180deg, #ffff00  0, #444 100%);
    box-shadow: inset 0 5px 20px black;
    text-shadow: 5px 5px 5px rgba(0, 0, 0, 0.3);
}
.loader:after{
    content: "";
    display: table;
    clear: both;
}
span{
    float: left;
    height: 100px;
    line-height: 120px;
    width: 50px;
}
.loader > span {
    border-left: 1px solid #444;
    border-right: 1px solid #222;
}
.loader-inner {
    position: absolute;
    height: 100%;
    width: 100%;
}
.loader-inner span {
    background: linear-gradient(180deg, white 0, #ddd 100%);
    animation: up 2s infinite;
}
@keyframes up {
    0% {
        margin-bottom: 0;
    }
    16% {
        margin-bottom: 100%;
        height: 20px;
    }
    50% {
        margin-bottom: 0;
    }
    100% {
        margin-bottom: 0;
    }
}
.loader-inner span:nth-child(2) {
    animation-delay: .142857s;
}
.loader-inner span:nth-child(3) {
    animation-delay: .285714s;
}
.loader-inner span:nth-child(4) {
    animation-delay: .428571s;
}
.loader-inner span:nth-child(5) {
    animation-delay: .571428s;
}
.loader-inner span:nth-child(6) {
    animation-delay: .714285s;
}
.loader-inner span:nth-child(7) {
    animation-delay: .857142s;
}
@media only screen and (max-width: 480px) {
    .loader{
        width: 77.8%;
        font-size: 200%;
    }
    span{
        width: 14.28%;
    }
}