CSS de precarga
.preloader-wrapper {
background: rgba(22, 22, 22, 0.3);
width: 100%; height: 100%;
position: fixed;
top: 0;
left: 0;
z-index: 10;
}
.preloader-wrapper > .preloader {
background: transparent url(https://graphiclineweb.files.wordpress.com/2013/10/ajaxloader.gif?w=604) no-repeat center top;
position: absolute;
min-width: 128px; /* image-width of loader */
min-height: 128px; /* image-height of loader */
box-sizing: border-box;
left: 50%;
top: 50%;
transform: translate(-50%, -50%);
padding-top: 148px; /* 128px image-height of loader + 20px margin */
text-align: center;
}
Odd Owl