*, *:before, *:after {
    margin: 0;
    padding: 0;
    outline: 0;
    box-sizing: border-box;
}
.contenedor_loader {
    background-color: #f3f3f3;
    position: fixed;
    width: 100vw;
    height: 100vh;
    z-index: 9999;
    transition: all 1.5s;
    display: flex;
    align-items: center;
    justify-content: center;
}
.preimg{
    width: 90%;
    align-content: center;
}
.loader,
.loader:before,
.loader:after {
    border-radius: 50%;
    width: 2.5em;
    height: 2.5em;
    animation: loader 1.5s infinite ease-in-out;
}
.loader {
    color: #4685Fa;
    font-size: 13px;
    position: relative;
    animation-delay: -0.16s;
}
.loader:before,
.loader:after {
    content: '';
    position: absolute;
    top: 0;
}
.loader:before{
    left: -3.5em;
    animation-delay: -0.32s;
}
.loader:after {
    left: 3.5em;
}

@keyframes loader{
    0%,
    80%,
    100%{
        box-shadow: 0 2.5em 0 -1.3em;
    }
    40% {
        box-shadow: 0 2.5em 0 0;
    }
}