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

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

canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

.hello {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-family: 'Google Sans', 'Inter', system-ui, -apple-system, sans-serif;
  font-size: clamp(2rem, 6vw, 5rem);
  font-weight: 300;
  color: #fff;
  letter-spacing: 0.02em;
  opacity: 0;
  animation: fadeIn 2s ease-out 0.8s forwards;
  text-shadow: 0 0 40px rgba(255, 255, 255, 0.2);
  z-index: 1;
  user-select: none;
}

.mode-toggle {
  position: fixed;
  top: 1.5rem;
  right: 1.5rem;
  z-index: 2;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  user-select: none;
}

.mode-icon {
  opacity: 0.7;
  transition: opacity 0.3s;
}

.mode-toggle:hover .mode-icon {
  opacity: 1;
}

.switch {
  position: relative;
  width: 40px;
  height: 22px;
  flex-shrink: 0;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  inset: 0;
  background: rgba(255, 255, 255, 0.15);
  border-radius: 22px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  cursor: pointer;
  transition: background 0.3s;
  backdrop-filter: blur(8px);
}

.slider::before {
  content: '';
  position: absolute;
  top: 2px;
  left: 2px;
  width: 16px;
  height: 16px;
  background: rgba(255, 255, 255, 0.7);
  border-radius: 50%;
  transition: transform 0.3s;
}

.switch input:checked + .slider::before {
  transform: translateX(18px);
}

.switch input:checked + .slider {
  background: rgba(255, 255, 255, 0.25);
}

@keyframes fadeIn {
  to { opacity: 1; }
}