:root {
  --control-bg: rgba(255,255,255,.86);
  --control-border: rgba(0,0,0,.07);
  --control-text: #111;
}

* { box-sizing: border-box; }
html, body {
  margin: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #fff;
}

body {
  font-family: Arial, Helvetica, sans-serif;
}

.viewer {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100dvh;
  background: #fff;
  overflow: hidden;
  user-select: none;
  -webkit-user-select: none;
  touch-action: none;
}

#viewer-canvas {
  width: 100%;
  height: 100%;
  display: block;
  background: #fff;
  cursor: grab;
  touch-action: none;
}

#viewer-canvas.dragging {
  cursor: grabbing;
}

.controls {
  position: absolute;
  right: max(16px, env(safe-area-inset-right));
  bottom: max(16px, env(safe-area-inset-bottom));
  display: flex;
  gap: 8px;
  opacity: 0;
  transform: translateY(6px);
  pointer-events: none;
  transition: opacity .22s ease, transform .22s ease;
}

.viewer:hover .controls,
.viewer.controls-visible .controls,
.controls:focus-within {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.control {
  width: 42px;
  height: 42px;
  border: 1px solid var(--control-border);
  border-radius: 999px;
  background: var(--control-bg);
  color: var(--control-text);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 19px;
  line-height: 1;
  cursor: pointer;
  box-shadow: 0 4px 18px rgba(0,0,0,.05);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition: transform .15s ease, background .15s ease;
}

.control:hover {
  transform: scale(1.04);
  background: #fff;
}

.loader {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  background: #fff;
  transition: opacity .35s ease, visibility .35s ease;
}

.loader.hidden {
  opacity: 0;
  visibility: hidden;
}

.spinner {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 2px solid #ececec;
  border-top-color: #999;
  animation: spin .8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

@media (hover: none) {
  .viewer:hover .controls {
    opacity: 0;
    pointer-events: none;
  }

  .viewer.controls-visible .controls {
    opacity: 1;
    pointer-events: auto;
  }
}