:root {
  color-scheme: dark;
  font-family: Arial, Helvetica, sans-serif;
  --accent: #ee2f3f;
  --surface: rgba(6, 30, 55, 0.86);
}

* { box-sizing: border-box; }

html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;
  background: #061e37;
}

#viewer {
  position: relative;
  display: grid;
  place-items: center;
  width: 100%;
  height: 100dvh;
  padding: max(8px, env(safe-area-inset-top)) 8px max(68px, calc(env(safe-area-inset-bottom) + 60px));
  background: radial-gradient(circle at 50% 40%, #123d66 0, #061e37 72%);
  touch-action: pan-y pinch-zoom;
  user-select: none;
}

#page-canvas {
  display: block;
  max-width: 100%;
  max-height: 100%;
  background: #061e37;
  box-shadow: 0 12px 38px rgba(0, 0, 0, 0.42);
}

#loading,
#error {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin: 0;
  padding: 24px;
  color: #fff;
  text-align: center;
  background: #061e37;
  z-index: 3;
}

#loading[hidden],
#error[hidden] { display: none; }

.spinner {
  width: 22px;
  height: 22px;
  border: 2px solid rgba(255, 255, 255, 0.24);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

#controls {
  position: fixed;
  left: 50%;
  bottom: max(10px, env(safe-area-inset-bottom));
  z-index: 4;
  display: flex;
  align-items: center;
  gap: 14px;
  min-height: 48px;
  padding: 5px 8px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 999px;
  background: var(--surface);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.28);
  backdrop-filter: blur(10px);
  transform: translateX(-50%);
}

#controls[hidden] { display: none; }

button {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  padding: 0 0 4px;
  border: 0;
  border-radius: 50%;
  color: #fff;
  font: 34px/1 Georgia, serif;
  background: rgba(255, 255, 255, 0.11);
  cursor: pointer;
}

button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

button:disabled {
  opacity: 0.28;
  cursor: default;
}

#page-number {
  min-width: 58px;
  color: #fff;
  font-size: 13px;
  font-variant-numeric: tabular-nums;
  text-align: center;
}

@media (min-width: 900px) {
  #viewer { padding-bottom: 76px; }
}

@media (prefers-reduced-motion: reduce) {
  .spinner { animation: none; }
}