:root {
  color-scheme: dark;
  background: #000;
}
* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body {
  margin: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #000;
  overscroll-behavior: none;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
body { position: fixed; inset: 0; }
#viewer {
  position: fixed;
  inset: 0;
  overflow: hidden;
  background: #000;
  touch-action: none;
  user-select: none;
}
#slide {
  position: absolute;
  left: 50%;
  top: 50%;
  width: 100%;
  height: 100%;
  object-fit: contain;
  transform-origin: center center;
  transform: translate(-50%, -50%) translate(0px, 0px) scale(1);
  will-change: transform;
  user-select: none;
  -webkit-user-drag: none;
}
#pageIndicator {
  position: fixed;
  left: 50%;
  bottom: max(10px, env(safe-area-inset-bottom));
  transform: translateX(-50%);
  padding: 5px 9px;
  border-radius: 999px;
  background: rgba(0,0,0,.55);
  color: rgba(255,255,255,.92);
  font-size: 12px;
  line-height: 1;
  z-index: 10;
  pointer-events: none;
  backdrop-filter: blur(6px);
}
#installBtn {
  position: fixed;
  top: max(10px, env(safe-area-inset-top));
  right: max(10px, env(safe-area-inset-right));
  z-index: 20;
  border: 0;
  border-radius: 999px;
  padding: 9px 13px;
  font: inherit;
  font-size: 14px;
  background: rgba(0,0,0,.65);
  color: #fff;
  backdrop-filter: blur(6px);
}
#help {
  position: fixed;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
  z-index: 30;
  width: min(88vw, 420px);
  padding: 14px 18px;
  border-radius: 14px;
  text-align: center;
  background: rgba(0,0,0,.72);
  color: white;
  font-size: 14px;
  line-height: 1.55;
  opacity: 0;
  pointer-events: none;
  transition: opacity .35s ease;
  backdrop-filter: blur(8px);
}
#help.show { opacity: 1; }
@media (display-mode: standalone) {
  #installBtn { display: none !important; }
}