:root {
  --bg: #0b1020;
  --fg: #e7eaf3;
  --muted: #aab0c0;
  --accent: #6ee7ff;
  --cube: 180px;
}

* { box-sizing: border-box; }

html, body {
  height: 100%;
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background: radial-gradient(1200px 700px at 20% 10%, #18224a 0%, var(--bg) 55%);
  color: var(--fg);
}

.page {
  min-height: 100%;
  display: grid;
  place-items: center;
  padding: 40px 16px;
  text-align: center;
  gap: 18px;
}

h1 {
  margin: 0;
  font-size: 32px;
  letter-spacing: 0.4px;
}

.sub {
  margin: -10px 0 0;
  color: var(--muted);
}

.stage {
  width: calc(var(--cube) * 1.8);
  height: calc(var(--cube) * 1.8);
  display: grid;
  place-items: center;
  perspective: 900px;
  perspective-origin: 50% 35%;
}

.cube {
  width: var(--cube);
  height: var(--cube);
  position: relative;
  transform-style: preserve-3d;
  will-change: transform;
}

.face {
  position: absolute;
  width: 100%;
  height: 100%;
  display: grid;
  place-items: center;
  font-weight: 700;
  letter-spacing: 1px;
  color: rgba(255, 255, 255, 0.92);
  border: 1px solid rgba(255, 255, 255, 0.18);
  box-shadow: 0 0 35px rgba(0, 0, 0, 0.25);
  background: linear-gradient(135deg, rgba(110, 231, 255, 0.30), rgba(120, 119, 198, 0.18));
  backdrop-filter: blur(4px);
}

/* Place faces */
.front  { transform: translateZ(calc(var(--cube) / 2)); }
.back   { transform: rotateY(180deg) translateZ(calc(var(--cube) / 2)); }
.right  { transform: rotateY(90deg) translateZ(calc(var(--cube) / 2)); }
.left   { transform: rotateY(-90deg) translateZ(calc(var(--cube) / 2)); }
.top    { transform: rotateX(90deg) translateZ(calc(var(--cube) / 2)); }
.bottom { transform: rotateX(-90deg) translateZ(calc(var(--cube) / 2)); }

.controls {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}

label {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--muted);
}

input[type="range"] {
  width: 220px;
}

button {
  background: rgba(110, 231, 255, 0.12);
  color: var(--fg);
  border: 1px solid rgba(110, 231, 255, 0.35);
  padding: 10px 14px;
  border-radius: 10px;
  cursor: pointer;
}

button:hover {
  background: rgba(110, 231, 255, 0.18);
}

footer {
  color: var(--muted);
}