:root {
  --bg-0: #021118;
  --bg-1: #063248;
  --plant-motion: 1.2;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  font-family: "Avenir Next", "Hiragino Sans", "Noto Sans JP", sans-serif;
  background:
    radial-gradient(circle at 20% 10%, #0a3a4b 0%, transparent 40%),
    radial-gradient(circle at 80% 90%, #0e5a73 0%, transparent 45%),
    linear-gradient(180deg, var(--bg-1), var(--bg-0));
  color: #dceef5;
}

body {
  display: grid;
  place-items: center;
  padding: 20px;
}

.aquarium-app {
  width: min(100%, 1080px);
}

#aquarium {
  position: relative;
  aspect-ratio: 16 / 9;
  border-radius: 22px;
  overflow: hidden;
  border: 1px solid rgba(165, 222, 241, 0.3);
  box-shadow:
    inset 0 0 0 1px rgba(200, 239, 252, 0.08),
    0 30px 60px rgba(0, 0, 0, 0.45);
  background: linear-gradient(180deg, #0b4961, #022532 78%);
}

#tank-bg,
#life-layer,
#plant-layer,
#back-particles,
#school-layer,
#front-particles,
#fish-layer,
.glass-highlight {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

#tank-bg {
  object-fit: cover;
  filter: saturate(1.1) contrast(1.05) blur(0.3px);
  opacity: 0.95;
}

#life-layer {
  z-index: 0;
  pointer-events: none;
  opacity: 0.38;
  mix-blend-mode: screen;
  filter: blur(0.25px);
}

#plant-layer {
  z-index: 1;
  pointer-events: none;
}

.plant {
  --amp: 9deg;
  --lean: 2deg;
  --base: 0.32;
  position: absolute;
  bottom: -14%;
  width: clamp(70px, 10vw, 140px);
  height: 98%;
  transform-origin: 50% 100%;
  opacity: var(--base);
  filter: blur(1.15px);
  animation:
    plant-sway calc(8.5s / var(--plant-motion)) cubic-bezier(0.42, 0, 0.35, 1) infinite,
    plant-pulse calc(13.2s / var(--plant-motion)) ease-in-out infinite;
}

.plant::before {
  content: "";
  position: absolute;
  left: 48.5%;
  bottom: 0;
  width: 4px;
  height: 100%;
  border-radius: 999px;
  background: linear-gradient(180deg, rgba(111, 170, 125, 0.04), rgba(92, 154, 109, 0.58));
}

.plant::after {
  content: "";
  position: absolute;
  inset: 8% 9% 0;
  border-radius: 60% 38% 56% 44%;
  background:
    radial-gradient(circle at 32% 26%, rgba(170, 230, 176, 0.22), transparent 55%),
    linear-gradient(180deg, rgba(123, 186, 130, 0.13), rgba(70, 121, 82, 0.56));
}

.p1 {
  left: 2%;
  --amp: 13deg;
  --base: 0.3;
  animation-delay: -2.6s;
}

.p2 {
  left: 14%;
  --amp: 11deg;
  --base: 0.26;
  height: 104%;
  animation-delay: -6.1s;
}

.p3 {
  left: 28%;
  --amp: 16deg;
  --lean: -1deg;
  --base: 0.29;
  animation-delay: -3.7s;
}

.p4 {
  left: 43%;
  --amp: 10deg;
  --base: 0.22;
  height: 108%;
  animation-delay: -8.5s;
}

.p5 {
  left: 57%;
  --amp: 14deg;
  --base: 0.25;
  animation-delay: -1.5s;
}

.p6 {
  left: 68%;
  --amp: 12deg;
  --base: 0.26;
  height: 106%;
  animation-delay: -9.2s;
}

.p7 {
  left: 80%;
  --amp: 15deg;
  --lean: -2deg;
  --base: 0.24;
  animation-delay: -4.2s;
}

.p8 {
  left: 90%;
  --amp: 9deg;
  --base: 0.2;
  height: 95%;
  animation-delay: -7.4s;
}

@keyframes plant-sway {
  0% {
    transform: rotate(calc(-1 * var(--amp) + var(--lean))) skewX(-2deg) scaleX(0.95);
  }
  18% {
    transform: rotate(calc(var(--amp) * 0.45 + var(--lean))) skewX(2.5deg) scaleX(1.05);
  }
  52% {
    transform: rotate(calc(var(--amp) + var(--lean))) skewX(5deg) scaleX(1.08);
  }
  74% {
    transform: rotate(calc(var(--amp) * -0.42 + var(--lean))) skewX(-3.2deg) scaleX(0.94);
  }
  100% {
    transform: rotate(calc(-1 * var(--amp) + var(--lean))) skewX(-2deg) scaleX(0.95);
  }
}

@keyframes plant-pulse {
  0% {
    opacity: calc(var(--base) - 0.03);
  }
  50% {
    opacity: calc(var(--base) + 0.09);
  }
  100% {
    opacity: calc(var(--base) - 0.03);
  }
}

#back-particles {
  z-index: 2;
}

#school-layer {
  z-index: 2;
  pointer-events: none;
}

#fish-layer {
  z-index: 3;
}

#front-particles {
  z-index: 4;
  pointer-events: none;
}

.fish {
  position: absolute;
  width: clamp(96px, 11vw, 148px);
  aspect-ratio: 220 / 120;
  transform-origin: 52% 52%;
  filter: drop-shadow(0 8px 8px rgba(0, 0, 0, 0.16));
  will-change: transform, opacity;
}

.fish--shark {
  width: clamp(126px, 15vw, 204px);
}

.fish--ray {
  width: clamp(132px, 16vw, 216px);
}

.fish-body,
.fish-tail {
  position: absolute;
  pointer-events: none;
  user-select: none;
  will-change: transform;
}

.fish-body {
  inset: 0;
  width: 100%;
  height: 100%;
  transform-origin: 52% 54%;
}

.fish-tail {
  left: -15%;
  top: 29%;
  width: 44%;
  height: 42%;
  transform-origin: 90% 50%;
  opacity: 0.95;
}

.school-fish {
  position: absolute;
  width: clamp(20px, 2.2vw, 32px);
  height: auto;
  opacity: 0.74;
  filter: blur(0.1px) drop-shadow(0 2px 2px rgba(0, 0, 0, 0.22));
  transform-origin: center center;
  will-change: transform, opacity;
}

.glass-highlight {
  z-index: 5;
  pointer-events: none;
  background:
    linear-gradient(
      105deg,
      rgba(255, 255, 255, 0.2) 0%,
      rgba(255, 255, 255, 0.06) 16%,
      transparent 30%,
      transparent 72%,
      rgba(255, 255, 255, 0.08) 88%,
      rgba(255, 255, 255, 0.12) 100%
    );
  mix-blend-mode: screen;
}