body {
  overscroll-behavior-x: none;
  overscroll-behavior-y: none;
}

body {
  position: relative;
  /* color: #777; */
  /* font-family: "Segoe Script", sans-serif; */
  /* font-size: max(20px, 4vw); */
  /* font-weight: 500; */
  width: 100vw;
  /* min-height: 100vh; */
  /* text-align: center; */
  /* line-height: 1; */
  overflow-x: hidden;
}
main {
  position: relative;
}

#bga {
  /* position: fixed; */
  top: 0;
  left: 0;
  width: 100vw;
  /* height: 100vh; */
  overflow: hidden;
  /* background-color: white; */
  /* background-image: url(https://images.unsplash.com/photo-1615800098779-1be32e60cca3?crop=entropy&cs=srgb&fm=jpg&ixid=M3wzMjM4NDZ8MHwxfHJhbmRvbXx8fHx8fHx8fDE2OTUyNDAwMTN8&ixlib=rb-4.0.3&q=85); */
  background-size: cover;
  background-repeat: no-repeat;
  -webkit-user-select: none;
     -moz-user-select: none;
      -ms-user-select: none;
          user-select: none;
  pointer-events: none;
  z-index: -1;
}
#bga > div {
  --size: 5vw;
  --symbol: "✽";

  --pos_x: 0vw;
  --duration_move: 7s;
  --delay_move: 0s;

  --duration_rotate: 1.5s;
  --delay_rotate: 0s;
  --duration_clip: 10s;
  --delay_clip: 0s;
  --hue: 0deg;

  position: absolute;
  top: 0;
  left: 0;
  font-size: clamp(15px, var(--size), 80px);
  font-family: "Noto Sans Symbols 2", sans-serif;
  transform-origin: center top;
  -webkit-animation: move var(--duration_move) var(--delay_move) linear infinite normal
    both;
          animation: move var(--duration_move) var(--delay_move) linear infinite normal
    both;
}
#bga span {
  display: block;
  position: relative;
  transform-origin: center;
  transform: rotate(0deg);
  -webkit-animation: rotate var(--duration_rotate) var(--delay_rotate) ease-in-out
    infinite alternate both;
          animation: rotate var(--duration_rotate) var(--delay_rotate) ease-in-out
    infinite alternate both;
}
#bga span:after {
  content: var(--symbol);
  -webkit-text-stroke: 0.5px rgba(0, 0, 0, 0.2);
  text-stroke: 0.5px rgba(0, 0, 0, 0.2);
  line-height: 1.2;
  position: relative;
  display: block;
  color: transparent;
  -webkit-background-clip: text;
          background-clip: text;
  /*
  filter: contrast(0.8) brightness(1.2) hue-rotate(var(--hue))
    drop-shadow(0px 0px 0.1px gold);
  */
  filter: brightness(1.2) hue-rotate(var(--hue));
  background-image: url(https://images.unsplash.com/photo-1580822115965-0b2532068eff?&ixid=M3wzMjM4NDZ8MHwxfHJhbmRvbXx8fHx8fHx8fDE2OTUxNDUzNzJ8&ixlib=rb-4.0.3&q=100&w=200&dpr=2);
  background-position: center;
  background-size: 200px auto; /* 必要に応じて調整 */
  background-repeat: repeat;
  transform: translateZ(0);
  -webkit-animation: bg1 var(--duration_clip) var(--delay_clip) linear infinite
    alternate both;
          animation: bg1 var(--duration_clip) var(--delay_clip) linear infinite
    alternate both;
}
#bga > div:nth-child(even) span:after {
  -webkit-animation-name: bg2;
          animation-name: bg2;
}
@-webkit-keyframes bg1 {
  0% {
    background-position: 0% 0%;
  }
  100% {
    background-position: 100% 100%;
  }
}
@keyframes bg1 {
  0% {
    background-position: 0% 0%;
  }
  100% {
    background-position: 100% 100%;
  }
}
@-webkit-keyframes bg2 {
  0% {
    background-position: 100% 0%;
  }
  100% {
    background-position: 0% 100%;
  }
}
@keyframes bg2 {
  0% {
    background-position: 100% 0%;
  }
  100% {
    background-position: 0% 100%;
  }
}
@-webkit-keyframes rotate {
  0% {
    transform: rotate(115deg);
  }
  100% {
    transform: rotate(245deg);
  }
}
@keyframes rotate {
  0% {
    transform: rotate(115deg);
  }
  100% {
    transform: rotate(245deg);
  }
}
@-webkit-keyframes move {
  0% {
    transform: translate3d(var(--pos_x), calc(0vh - var(--size)), 0);
  }
  100% {
    transform: translate3d(var(--pos_x), 100vh, 0);
  }
}
@keyframes move {
  0% {
    transform: translate3d(var(--pos_x), calc(0vh - var(--size)), 0);
  }
  100% {
    transform: translate3d(var(--pos_x), 100vh, 0);
  }
}

/* 以下、ひたすら量産 */
#bga > div:nth-child(23n + 1) {
  --symbol: "🟄";
}
#bga > div:nth-child(23n + 2) {
  --symbol: "❉";
}
#bga > div:nth-child(23n + 3) {
  --symbol: "🟉";
}
#bga > div:nth-child(23n + 4) {
  --symbol: "❈";
}
#bga > div:nth-child(23n + 5) {
  --symbol: "✣";
}
#bga > div:nth-child(23n + 6) {
  --symbol: "🞯";
}
#bga > div:nth-child(23n + 7) {
  --symbol: "🟎";
}
#bga > div:nth-child(23n + 8) {
  --symbol: "♦";
}
#bga > div:nth-child(23n + 9) {
  --symbol: "✢";
}
#bga > div:nth-child(23n + 10) {
  --symbol: "🞵";
}
#bga > div:nth-child(23n + 11) {
  --symbol: "✤";
}
#bga > div:nth-child(23n + 12) {
  --symbol: "✦";
}
#bga > div:nth-child(23n + 13) {
  --symbol: "❇";
}
#bga > div:nth-child(23n + 14) {
  --symbol: "🞻";
}
#bga > div:nth-child(23n + 15) {
  --symbol: "✶";
}
#bga > div:nth-child(23n + 16) {
  --symbol: "✳";
}
#bga > div:nth-child(23n + 17) {
  --symbol: "❊";
}
#bga > div:nth-child(23n + 18) {
  --symbol: "🟄";
}
#bga > div:nth-child(23n + 19) {
  --symbol: "✻";
}
#bga > div:nth-child(23n + 20) {
  --symbol: "❋";
}
#bga > div:nth-child(23n + 21) {
  --symbol: "✷";
}
#bga > div:nth-child(23n + 22) {
  --symbol: "✴";
}

#bga > div:nth-child(21n + 1) {
  --pos_x: 5vw;
}
#bga > div:nth-child(21n + 2) {
  --pos_x: 10vw;
}
#bga > div:nth-child(21n + 3) {
  --pos_x: 15vw;
}
#bga > div:nth-child(21n + 4) {
  --pos_x: 20vw;
}
#bga > div:nth-child(21n + 5) {
  --pos_x: 25vw;
}
#bga > div:nth-child(21n + 6) {
  --pos_x: 30vw;
}
#bga > div:nth-child(21n + 7) {
  --pos_x: 35vw;
}
#bga > div:nth-child(21n + 8) {
  --pos_x: 40vw;
}
#bga > div:nth-child(21n + 9) {
  --pos_x: 45vw;
}
#bga > div:nth-child(21n + 10) {
  --pos_x: 50vw;
}
#bga > div:nth-child(21n + 11) {
  --pos_x: 55vw;
}
#bga > div:nth-child(21n + 12) {
  --pos_x: 60vw;
}
#bga > div:nth-child(21n + 13) {
  --pos_x: 65vw;
}
#bga > div:nth-child(21n + 14) {
  --pos_x: 70vw;
}
#bga > div:nth-child(21n + 15) {
  --pos_x: 75vw;
}
#bga > div:nth-child(21n + 16) {
  --pos_x: 80vw;
}
#bga > div:nth-child(21n + 17) {
  --pos_x: 85vw;
}
#bga > div:nth-child(21n + 18) {
  --pos_x: 90vw;
}
#bga > div:nth-child(21n + 19) {
  --pos_x: 95vw;
}
#bga > div:nth-child(21n + 20) {
  --pos_x: 100vw;
}

#bga > div:nth-child(12n + 1) {
  --hue: 30deg;
}
#bga > div:nth-child(12n + 2) {
  --hue: 270deg;
}
#bga > div:nth-child(12n + 3) {
  --hue: 90deg;
}
#bga > div:nth-child(12n + 4) {
  --hue: 150deg;
}
#bga > div:nth-child(12n + 5) {
  --hue: 330deg;
}
#bga > div:nth-child(12n + 6) {
  --hue: 180deg;
}
#bga > div:nth-child(12n + 7) {
  --hue: 60deg;
}
#bga > div:nth-child(12n + 8) {
  --hue: 210deg;
}
#bga > div:nth-child(12n + 9) {
  --hue: 120deg;
}
#bga > div:nth-child(12n + 10) {
  --hue: 240deg;
}
#bga > div:nth-child(12n + 11) {
  --hue: 300deg;
}

#bga > div:nth-child(8n + 1) {
  --delay_move: -4s;
}
#bga > div:nth-child(8n + 2) {
  --delay_move: -5s;
}
#bga > div:nth-child(8n + 3) {
  --delay_move: -6s;
}
#bga > div:nth-child(8n + 4) {
  --delay_move: -1s;
}
#bga > div:nth-child(8n + 5) {
  --delay_move: -2s;
}
#bga > div:nth-child(8n + 6) {
  --delay_move: -3s;
}
#bga > div:nth-child(8n + 7) {
  --delay_move: -7s;
}

#bga > div:nth-child(9n + 1) {
  --duration_move: 7.5s;
}
#bga > div:nth-child(9n + 2) {
  --duration_move: 8s;
}
#bga > div:nth-child(9n + 3) {
  --duration_move: 8.5s;
}
#bga > div:nth-child(9n + 4) {
  --duration_move: 9s;
}
#bga > div:nth-child(9n + 5) {
  --duration_move: 5.5s;
}
#bga > div:nth-child(9n + 6) {
  --duration_move: 6s;
}
#bga > div:nth-child(9n + 7) {
  --duration_move: 6.5s;
}
#bga > div:nth-child(9n + 8) {
  --duration_move: 7.8s;
}

#bga > div:nth-child(7n + 1) {
  --delay_rotate: 0.3s;
}
#bga > div:nth-child(7n + 2) {
  --delay_rotate: 0.6s;
}
#bga > div:nth-child(7n + 3) {
  --delay_rotate: 0.9s;
}
#bga > div:nth-child(7n + 4) {
  --delay_rotate: -0.3s;
}
#bga > div:nth-child(7n + 5) {
  --delay_rotate: -0.6s;
}
#bga > div:nth-child(7n + 6) {
  --delay_rotate: -0.9s;
}

#bga > div:nth-child(6n + 1) {
  --duration_rotate: 1s;
}
#bga > div:nth-child(6n + 2) {
  --duration_rotate: 1.6s;
}
#bga > div:nth-child(6n + 3) {
  --duration_rotate: 1.1s;
}
#bga > div:nth-child(6n + 4) {
  --duration_rotate: 1.2s;
}
#bga > div:nth-child(6n + 5) {
  --duration_rotate: 1.3s;
}

#bga > div:nth-child(5n + 1) {
  --size: 3vw;
}
#bga > div:nth-child(5n + 2) {
  --size: 4vw;
}
#bga > div:nth-child(5n + 3) {
  --size: 6vw;
}
#bga > div:nth-child(5n + 4) {
  --size: 7vw;
}