*{box-sizing:border-box;margin:0;padding:0}html,body{min-height:100%;background:#374151}#viewer{display:flex;flex-direction:column;align-items:center;padding:16px;gap:16px}canvas{display:block;max-width:100%;height:auto!important;background:#fff;box-shadow:0 4px 20px #0000004d}canvas+canvas{margin-top:0}.message{position:fixed;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:16px;color:#e5e7eb;background:#374151}.message[hidden]{display:none}.message.error{color:#fecaca}.spinner{width:34px;height:34px;border:4px solid rgba(255,255,255,.2);border-top-color:#fff;border-radius:50%;animation:spin .8s linear infinite}.spinner[hidden]{display:none}@keyframes spin{to{transform:rotate(360deg)}}