.firstview-pics {
    position: absolute;
    width: 100%;
    height: 100vh;
    overflow: hidden;
    pointer-events: none;
}

.firstview-pic {
    width: 100%;
    height: 100vh;
    background-position: center;
    background-size: cover;
    background-repeat: no-repeat;
    position: absolute;
    top: 0;
    opacity: 0;
    animation: slider 21s linear infinite;
    z-index: -1;
}

.firstview-pic:nth-child(1) {
    animation-delay: 0s;
    background-image: url(../image/f-01.jpg);
}

.firstview-pic:nth-child(2) {
  animation-delay: 7s;
  background-image: url(../image/f-02.jpg);
}

.firstview-pic:nth-child(3) {
  animation-delay: 14s;
  background-image: url(../image/message.jpg);
}

@keyframes slider {
  0% {
      opacity: 0;
      transform: scale(1.15);
  }
  4.16% {
      opacity: 1;
  }
  33.33% {
      opacity: 1;
  }
  41.66% {
      opacity: 0;
      transform: scale(1);
  }
  100% {
      opacity: 0;
  }
}