* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  width: 100vw;
  height: 100vh;
  overflow: hidden;
  background: #000;
}

#aquarium {
  position: relative;
  width: 100%;
  height: 100%;
  background: linear-gradient(180deg, #0a1f44 0%, #0d3b6e 40%, #0a4f5e 75%, #0d6e5e 100%);
  overflow: hidden;
}



/* Sandy floor */
#aquarium::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 60px;
  background: linear-gradient(180deg, #c8a84b 0%, #a0783a 100%);
  border-radius: 50% 50% 0 0 / 20px 20px 0 0;
  z-index: 2;
}

#bubbles-layer,
#fish-layer {
  position: absolute;
  inset: 0;
}

#bubbles-layer { z-index: 3; }
#fish-layer    { z-index: 4; }

#hint {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: rgba(255,255,255,0.35);
  font-family: 'Segoe UI', sans-serif;
  font-size: clamp(1.2rem, 3vw, 2rem);
  font-weight: 300;
  letter-spacing: 0.15em;
  pointer-events: none;
  z-index: 10;
  transition: opacity 0.6s;
}

#hint.hidden {
  opacity: 0;
}

/* ── Fish ── */
.fish {
  position: absolute;
  display: flex;
  align-items: center;
  gap: 0;
  cursor: default;
  user-select: none;
  /* animation applied via JS */
}

.fish svg {
  display: block;
}

/* ── Bubbles ── */
.bubble {
  position: absolute;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, rgba(255,255,255,0.55), rgba(255,255,255,0.05));
  border: 1px solid rgba(255,255,255,0.25);
  animation: rise linear forwards;
  pointer-events: none;
}

@keyframes rise {
  0%   { transform: translateY(0)   translateX(0);   opacity: 0.8; }
  50%  { transform: translateY(-40vh) translateX(8px);  opacity: 0.6; }
  100% { transform: translateY(-85vh) translateX(-4px); opacity: 0; }
}

/* ── Fish swim animations ── */
@keyframes swim-right {
  0%   { transform: translateX(0); }
  100% { transform: translateX(calc(100vw + 220px)); }
}

@keyframes swim-left {
  0%   { transform: translateX(0); }
  100% { transform: translateX(calc(-100vw - 220px)); }
}

@keyframes bob {
  0%, 100% { margin-top: 0; }
  50%       { margin-top: 18px; }
}