html, body { margin: 0; height: 100%; overflow: hidden; background: #0d1020; user-select: none; -webkit-user-select: none; }
  #app { position: fixed; inset: 0; }
  #app canvas { display: block; width: 100%; height: 100%; outline: none; }
  #ui-root { position: fixed; inset: 0; pointer-events: none; z-index: 10; }
  #fade { position: fixed; inset: 0; background: #0d1020; opacity: 1; pointer-events: all; z-index: 50; transition: opacity 600ms ease; }
  #boot-error { display: none; position: fixed; left: 50%; top: 50%; transform: translate(-50%, -50%); z-index: 60; color: #fff; font: 600 16px/1.4 system-ui, sans-serif; background: #c0263d; padding: 16px 20px; border-radius: 12px; max-width: 520px; }