.u-checkbox-ninja {
  --ninja-black: #000000;
  --star-core: #ffffff;
  --star-glow: #a3e4ff;
  --blade-primary: #1a1a1a;
  --blade-edge: #5d9bff;
  --constellation: #222222;
  --label-text: #e0e0e0;

  display: flex;
  align-items: center;
  gap: 1rem;
  font-family: "Orbitron", sans-serif;
  font-weight: 500;
  color: var(--label-text);
  cursor: pointer;
  user-select: none;
  transition: color 0.3s ease;
  background: var(--ninja-black);
  padding: 1rem;
  border-radius: 0.5rem;
}

.u-checkbox-ninja:hover {
  color: var(--star-glow);
}

.u-checkbox-ninja input {
  display: none;
}

.ninja-container {
  width: 4rem;
  height: 4rem;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  background: radial-gradient(circle, var(--constellation), #000000);
  border-radius: 50%;
  border: 2px solid var(--blade-edge);
  box-shadow:
    0 0 0.8rem rgba(93, 155, 255, 0.4),
    inset 0 0 1rem rgba(0, 0, 0, 0.9);
  transform-style: preserve-3d;
  transition: all 0.4s cubic-bezier(0.68, -0.55, 0.27, 1.55);
  overflow: hidden;
}

.u-checkbox-ninja:hover .ninja-container {
  transform: scale(1.08) rotate(10deg);
  box-shadow:
    0 0 1.5rem rgba(93, 155, 255, 0.7),
    inset 0 0 1rem rgba(0, 0, 0, 0.7);
}

.blade {
  position: absolute;
  width: 1.4rem;
  height: 1.4rem;
  background: linear-gradient(135deg, var(--blade-primary), #000000);
  border: 1px solid var(--blade-edge);
  transform-origin: center center;
  transition: transform 0.6s cubic-bezier(0.76, 0, 0.24, 1);
  clip-path: polygon(50% 0%, 100% 100%, 0% 100%);
  transform: rotate(calc(var(--i) * 90deg)) translateY(-0.7rem) rotate(180deg);
  filter: drop-shadow(0 0 0.2rem rgba(93, 155, 255, 0.5));
  z-index: 1;
}

.u-checkbox-ninja input:checked + .ninja-container .blade {
  transform: rotate(calc(var(--i) * 90deg)) translateY(-0.7rem) rotate(270deg);
  background: linear-gradient(135deg, var(--blade-edge), #000000);
  box-shadow: 0 0 0.5rem var(--blade-edge);
}

.core {
  width: 0.8rem;
  height: 0.8rem;
  background: radial-gradient(circle, var(--star-core), var(--star-glow));
  border-radius: 50%;
  transform: scale(0);
  transition: transform 0.4s 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
  box-shadow: 0 0 0.75rem var(--star-glow);
  z-index: 2;
}

.u-checkbox-ninja input:checked + .ninja-container .core {
  transform: scale(1);
  animation: pulse-star 1.8s infinite alternate;
}

@keyframes pulse-star {
  0% {
    box-shadow: 0 0 0.5rem var(--star-glow);
  }
  100% {
    box-shadow:
      0 0 1.5rem var(--star-core),
      0 0 3rem rgba(163, 228, 255, 0.6);
  }
}