* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { background: #f3f3f3; }
body { display: flex; justify-content: center; padding: 20px; font-family: -apple-system, 'Segoe UI', Roboto, Arial, sans-serif; }
#stage-wrapper { margin: 0 auto; overflow: hidden; }
#stage-stack { transform-origin: top left; }
.stage { position: relative; overflow: hidden; box-shadow: 0 10px 30px rgba(0,0,0,0.15); }