.cosmic-background {
  position: fixed;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  pointer-events: none;
  contain: strict;
  background: #000;
  isolation: isolate;
}

.scene {
  z-index: 4;
}

.universe-expansion-layer {
  background: rgba(0, 0, 0, 0.48);
}

.cosmic-star-canvas,
.cosmic-atmosphere,
.cosmic-lens {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.cosmic-star-canvas {
  z-index: 0;
}

.cosmic-atmosphere {
  z-index: 1;
  opacity: 0;
}

.cosmic-background[data-theme="nebula"] .cosmic-atmosphere {
  opacity: 1;
  inset: -18%;
  width: 136%;
  height: 136%;
  background:
    radial-gradient(ellipse 62% 42% at 4% 28%, rgba(27, 104, 137, 0.24), rgba(4, 31, 51, 0.08) 42%, transparent 69%),
    radial-gradient(ellipse 58% 46% at 95% 73%, rgba(126, 38, 125, 0.2), rgba(30, 30, 90, 0.08) 43%, transparent 72%),
    conic-gradient(from 205deg at 54% 48%, transparent 0deg, rgba(29, 99, 117, 0.11) 38deg, transparent 84deg, rgba(99, 40, 130, 0.1) 146deg, transparent 214deg);
  filter: blur(34px) saturate(1.28);
  mix-blend-mode: screen;
  animation: cosmic-nebula-breathe 18s ease-in-out infinite alternate;
}

.cosmic-background[data-theme="nebula"] .cosmic-atmosphere::before,
.cosmic-background[data-theme="nebula"] .cosmic-atmosphere::after {
  content: "";
  position: absolute;
  inset: 7% 4%;
  background:
    linear-gradient(117deg, transparent 16%, rgba(72, 167, 178, 0.08) 38%, transparent 56%),
    linear-gradient(302deg, transparent 34%, rgba(169, 77, 151, 0.07) 55%, transparent 73%);
  filter: blur(28px);
}

.cosmic-background[data-theme="nebula"] .cosmic-atmosphere::after {
  transform: rotate(17deg) scale(1.08);
  opacity: 0.7;
}

.cosmic-lens {
  z-index: 1;
  left: 50%;
  top: 50%;
  inset: auto;
  width: min(96vmin, 980px);
  height: min(72vmin, 735px);
  border-radius: 50%;
  transform: translate(-50%, -50%) rotate(-13deg);
  opacity: 0;
}

.cosmic-background[data-theme="vortex"] .cosmic-lens {
  opacity: 0.7;
  border: 1px solid rgba(124, 207, 255, 0.16);
  box-shadow:
    0 0 16px rgba(89, 195, 255, 0.08),
    inset 0 0 28px rgba(190, 80, 255, 0.07);
  animation: cosmic-lens-turn 26s linear infinite;
}

.cosmic-background[data-theme="vortex"] .cosmic-lens::before,
.cosmic-background[data-theme="vortex"] .cosmic-lens::after {
  content: "";
  position: absolute;
  border-radius: 50%;
  border: 1px solid transparent;
}

.cosmic-background[data-theme="vortex"] .cosmic-lens::before {
  inset: 8% -8%;
  border-top-color: rgba(255, 105, 201, 0.2);
  border-bottom-color: rgba(89, 218, 255, 0.14);
  transform: rotate(22deg);
}

.cosmic-background[data-theme="vortex"] .cosmic-lens::after {
  inset: 19% 4%;
  border-left-color: rgba(255, 221, 90, 0.14);
  border-right-color: rgba(159, 89, 255, 0.18);
  transform: rotate(-18deg);
}

.cosmic-meteor,
.cosmic-electric {
  position: absolute;
  left: 0;
  top: 0;
  display: block;
  pointer-events: none;
  user-select: none;
  transform-origin: center;
  backface-visibility: hidden;
  will-change: transform, opacity;
}

.reference-meteor-field {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
}

.reference-meteor-field-behind {
  z-index: 1;
}

.reference-meteor-field-front {
  z-index: 5;
}

.reference-meteor {
  position: absolute;
  left: 0;
  top: 0;
  display: block;
  height: auto;
  opacity: 0;
  pointer-events: none;
  user-select: none;
  transform-origin: center;
  backface-visibility: hidden;
  will-change: transform, opacity;
  mix-blend-mode: screen;
}

.cosmic-meteor {
  z-index: var(--cosmic-depth);
  width: var(--meteor-width);
  height: auto;
  opacity: 0;
  filter:
    hue-rotate(var(--meteor-hue))
    saturate(var(--meteor-saturation))
    brightness(var(--meteor-light))
    drop-shadow(0 0 var(--meteor-glow) var(--meteor-glow-color));
  animation: cosmic-meteor-flight var(--meteor-duration) linear var(--meteor-delay) infinite;
}

.cosmic-meteor.is-tangent-flight {
  left: 0;
  top: 0;
  offset-path: var(--meteor-path);
  offset-rotate: auto 0deg;
  transform: translate(-50%, -50%) scale(var(--meteor-scale-start));
  animation: cosmic-meteor-tangent-flight var(--meteor-duration) linear var(--meteor-delay) infinite;
}

.cosmic-electric {
  z-index: var(--cosmic-depth);
  width: var(--electric-width);
  height: auto;
  opacity: 0;
  mix-blend-mode: screen;
  filter:
    hue-rotate(var(--electric-hue))
    saturate(var(--electric-saturation))
    brightness(var(--electric-light))
    drop-shadow(0 0 var(--electric-glow) var(--electric-glow-color));
  animation:
    cosmic-electric-drift var(--electric-duration) ease-in-out var(--electric-delay) infinite,
    cosmic-electric-flicker var(--electric-flicker) steps(2, end) var(--electric-delay) infinite;
}

.cosmic-background[data-theme="storm"] .cosmic-meteor.is-near,
.cosmic-background[data-theme="nebula"] .cosmic-meteor.is-near {
  mix-blend-mode: screen;
}

.cosmic-background[data-theme="vortex"] .cosmic-meteor,
.cosmic-background[data-theme="vortex"] .cosmic-electric {
  left: 0;
  top: 0;
  offset-path: var(--vortex-path);
  offset-rotate: auto;
  transform: translate(-50%, -50%) scale(var(--vortex-scale));
}

.cosmic-background[data-theme="vortex"] .cosmic-meteor {
  animation: cosmic-vortex-meteor var(--meteor-duration) linear var(--meteor-delay) infinite;
}

.cosmic-background[data-theme="vortex"] .cosmic-electric {
  animation:
    cosmic-vortex-electric var(--electric-duration) linear var(--electric-delay) infinite,
    cosmic-electric-flicker var(--electric-flicker) steps(2, end) var(--electric-delay) infinite;
}

@keyframes cosmic-meteor-flight {
  0%, 5% {
    opacity: 0;
    transform:
      translate3d(var(--meteor-start-x), var(--meteor-start-y), 0)
      rotate(var(--meteor-angle))
      scale(var(--meteor-scale-start));
  }
  9% { opacity: var(--meteor-opacity); }
  78% { opacity: calc(var(--meteor-opacity) * 0.94); }
  93%, 100% {
    opacity: 0;
    transform:
      translate3d(var(--meteor-end-x), var(--meteor-end-y), 0)
      rotate(var(--meteor-angle))
      scale(var(--meteor-scale-end));
  }
}

@keyframes cosmic-meteor-tangent-flight {
  0%, 4% {
    offset-distance: 0%;
    opacity: 0;
    transform: translate(-50%, -50%) scale(var(--meteor-scale-start));
  }
  9% { opacity: var(--meteor-opacity); }
  76% { opacity: calc(var(--meteor-opacity) * 0.96); }
  94%, 100% {
    offset-distance: 100%;
    opacity: 0;
    transform: translate(-50%, -50%) scale(var(--meteor-scale-end));
  }
}

@keyframes cosmic-electric-drift {
  0%, 7% {
    opacity: 0;
    transform:
      translate3d(var(--electric-x), var(--electric-y), 0)
      rotate(var(--electric-angle))
      scale(var(--electric-scale));
  }
  12%, 46% { opacity: var(--electric-opacity); }
  60% { opacity: calc(var(--electric-opacity) * 0.34); }
  72% { opacity: calc(var(--electric-opacity) * 0.88); }
  92%, 100% {
    opacity: 0;
    transform:
      translate3d(calc(var(--electric-x) + var(--electric-drift-x)), calc(var(--electric-y) + var(--electric-drift-y)), 0)
      rotate(calc(var(--electric-angle) + var(--electric-turn)))
      scale(calc(var(--electric-scale) * 1.06));
  }
}

@keyframes cosmic-vortex-meteor {
  0%, 4% { offset-distance: 0%; opacity: 0; }
  9% { opacity: var(--meteor-opacity); }
  82% { opacity: calc(var(--meteor-opacity) * 0.96); }
  95%, 100% { offset-distance: 100%; opacity: 0; }
}

@keyframes cosmic-vortex-electric {
  0%, 5% { offset-distance: 0%; opacity: 0; }
  12%, 45% { opacity: var(--electric-opacity); }
  62% { opacity: calc(var(--electric-opacity) * 0.38); }
  76% { opacity: var(--electric-opacity); }
  94%, 100% { offset-distance: 100%; opacity: 0; }
}

@keyframes cosmic-electric-flicker {
  0%, 15%, 24%, 38%, 49%, 64%, 78%, 100% { visibility: visible; }
  19%, 43%, 70% { visibility: hidden; }
}

@keyframes cosmic-nebula-breathe {
  from { transform: translate3d(-1.8%, 0.8%, 0) rotate(-2deg) scale(1); opacity: 0.78; }
  to { transform: translate3d(2.4%, -1.4%, 0) rotate(3deg) scale(1.055); opacity: 1; }
}

@keyframes cosmic-lens-turn {
  from { transform: translate(-50%, -50%) rotate(-13deg); }
  to { transform: translate(-50%, -50%) rotate(347deg); }
}

.expansion-child {
  width: 20.5%;
  cursor: pointer;
  outline: none;
}

.universe-child-cluster {
  cursor: grab;
  touch-action: none;
}

.universe-child-cluster.is-dragging,
.universe-child-cluster.is-dragging .expansion-child {
  cursor: grabbing;
}

.expansion-child::after {
  content: "";
  position: absolute;
  inset: -10px;
  z-index: 5;
  border-radius: 50%;
}

.expansion-child:hover,
.expansion-child:focus-visible {
  filter: brightness(1.22) saturate(1.08) !important;
}

@media (max-width: 720px) {
  .cosmic-background[data-theme="nebula"] .cosmic-atmosphere {
    filter: blur(22px) saturate(1.18);
  }
}

@media (prefers-reduced-motion: reduce) {
  .cosmic-meteor,
  .cosmic-electric {
    animation-duration: 22s, 10s;
  }
}