Lotka–Volterra (Hastings–Powell) — dx/dt=x(1−x)−a₁xy/(1+b₁x), dy/dt=a₁xy/(1+b₁x)−a₂yz/(1+b₂y)−d₁y, dz/dt=a₂yz/(1+b₂y)−d₂z. Classic a₁=5 b₁=3 a₂=0.1 b₂=2 d₁=0.4 d₂=0.01. Dual a₁+d₁ sliders; b₁/a₂/b₂/d₂ fixed. Display embed (x,y,z). Distinct from brusselator.html, operon.html, oregonator.html, willamowski.html, bell.html. Bulk centroid ≈ (0.7471, 0.1374, 9.0611). RK4 food-chain chaos. Gold low-alpha trail, cap 650. RM = settled silhouette, no animate-on.