#fep-app{max-width:1000px;margin:20px auto;font-family:Arial}.fep-header{background:#eee;padding:10px}.fep-product{margin-top:5px}.fep-shapes{border:1px solid #ccc;padding:10px;margin:10px 0}.fep-shapes button{margin:5px;padding:10px;cursor:pointer}.fep-room{display:flex;gap:10px;margin-bottom:10px}#fep-canvas{border:1px solid #ccc;background:#fafafa}.fep-result{margin:10px 0;font-weight:700}#fep-calc{background:#28a745;color:#fff;padding:10px 15px;border:none;cursor:pointer}