body {
    margin:0;
    padding:0;
}

.all {
    position: relative;
    margin:0 auto;
}

.dot {
    max-width: auto;
    max-height: auto;
}

.a01 {
    position:absolute;
    left:0;
    top:0;
    z-index:99;
}

.dot img {
    max-width: 100%;
    max-height: 100%;
    animation: dot-ani 1s infinite;
}

@keyframes dot-ani {
    0% {opacity:0}
    50% {opacity:1}
    100% {opacity:0}
}