/* Spinner overlay */
#loader {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(255,255,255,0.9);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 9999;
}

/* Controls */
#controls {
  margin: 10px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 6px;
}

button {
  margin: 2px;
}

/* Flipbook container */
#book {
  width: 95vw;
  height: 75vh;
}

/* Pages */
.page {
  background: white;
  display: flex;
  justify-content: center;
  align-items: center;
}

canvas {
  width: 100%;
  height: auto;
}

/* Dark mode */
.dark-mode {
  background-color: #121212;
}

.dark-mode .page {
  background-color: #1e1e1e;
}

/* 📱 MOBILE OPTIMIZATION */
@media (max-width: 768px) {

  #book {
    width: 100vw;
    height: 80vh;
  }
  
  #controls {
    width: 100%;
    padding: 5px;
  }

  button {
    flex: 1 1 45%;
    font-size: 14px;
    padding: 8px;
  }

  /* Optional: hide text, keep icons (clean UI) */
  button span {
    display: none;
  }
}

/* 📱 EXTRA SMALL DEVICES */
@media (max-width: 480px) {

  #book {
    height: 78vh;
  }

  button {
    font-size: 12px;
    padding: 6px;
  }
}