:root {
  --fb-theme: #222222;
  --fb-bg: #111111;
  --fb-text: #ffffff;
}

html, body {
  height: 100%;
}

body {
  margin: 0;
  background: var(--fb-bg);
  color: var(--fb-text);
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, Helvetica Neue, Arial, sans-serif;
}

.fb-root {
  display: grid;
  grid-template-rows: auto 1fr auto;
  height: 100vh;
}

.fb-toolbar {
  display: flex;
  gap: .5rem;
  align-items: center;
  padding: .5rem 1rem;
  background: linear-gradient(180deg, rgba(255,255,255,0.05), rgba(0,0,0,0.1));
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.fb-btn {
  background: var(--fb-theme);
  color: var(--fb-text);
  border: none;
  border-radius: 6px;
  padding: .5rem .75rem;
  cursor: pointer;
}

.fb-canvas {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 1rem;
  padding: 1rem;
  overflow: hidden;
  background: var(--fb-bg);
}

.fb-stage {
  display: grid;
  place-items: center;
  overflow: hidden;
  background: var(--fb-bg);
  border-radius: 12px;
  cursor: grab;
}

.fb-book {
  position: relative;
  perspective: 2000px;
  transform-style: preserve-3d;
  user-select: none;
  background: var(--fb-bg);
}

.fb-page {
  position: absolute;
  top: 0;
  left: 0;
  transform-origin: left center;
  backface-visibility: hidden;
  transition: transform var(--anim, 400ms) ease, box-shadow var(--anim, 400ms) ease;
  box-shadow: 0 10px 30px rgba(0,0,0,0.25);
  background: var(--fb-bg);
}

.fb-page img { display: block; width: 100%; height: 100%; object-fit: var(--fit, contain); }

/* Sombras y borde para efecto físico */
.fb-page::after {
  content: '';
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: radial-gradient(ellipse at left, rgba(0,0,0,0.18), transparent 60%),
              radial-gradient(ellipse at right, rgba(0,0,0,0.14), transparent 60%);
  opacity: 0.6;
}

.fb-thumbs {
  overflow: auto;
  display: grid;
  gap: .5rem;
  grid-auto-rows: min-content;
}

.fb-thumb { cursor: pointer; border-radius: 6px; overflow: hidden; border: 1px solid rgba(255,255,255,0.1); }
.fb-thumb img { display:block; width:100%; height:auto; }

.fb-footer {
  display: flex;
  gap: .75rem;
  align-items: center;
  padding: .5rem 1rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.fb-progress { height: 6px; background: rgba(255,255,255,0.15); border-radius: 999px; overflow: hidden; flex: 1; }
.fb-progress > div { height: 100%; background: var(--fb-theme); width: 0%; }

/* Estilos para sobrescribir PageFlip */
.stf__parent {
  background: var(--fb-bg) !important;
}

.stf__block {
  background: var(--fb-bg) !important;
}

.stf__item {
  background: var(--fb-bg) !important;
}

.stf__canvas {
  background: var(--fb-bg) !important;
}

#book * {
  background-color: var(--fb-bg) !important;
}