/* ---------- Combat VFX overlays (js/vfx.js) ---------- */
/* Low-hull warning: a soft red edge that breathes while the player's hull is under 30%. Above the canvas, under the HUD. */
#vignette { position: fixed; inset: 0; z-index: 3; pointer-events: none; opacity: 0; transition: opacity .5s;
  background: radial-gradient(ellipse closest-side at center, rgba(215, 28, 14, 0) 70%, rgba(215, 28, 14, .3) 88%, rgba(220, 24, 12, .62) 100%);
  box-shadow: inset 0 0 9vmin 1vmin rgba(215, 24, 12, .55); }   /* saturated: a dull red over the teal sea mixes to grey */
#vignette.on { animation: vigPulse 1.15s ease-in-out infinite; }
@keyframes vigPulse { 0%, 100% { opacity: .4; } 50% { opacity: .85; } }
@media (prefers-reduced-motion: reduce) { #vignette.on { animation: none; opacity: .7; } }