/* ======================================
   Canvas Area
   ====================================== */
#canvas-area {
  flex: 1;
  overflow: auto;
  background: var(--bg-canvas);
  position: relative;
  /* Checkerboard pattern for transparency */
  background-image:
    linear-gradient(45deg, rgba(255,255,255,0.02) 25%, transparent 25%),
    linear-gradient(-45deg, rgba(255,255,255,0.02) 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, rgba(255,255,255,0.02) 75%),
    linear-gradient(-45deg, transparent 75%, rgba(255,255,255,0.02) 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0;
}

#canvas-container {
  position: relative;
  margin: var(--space-8) auto;
  width: fit-content;
  box-shadow: var(--shadow-xl);
  border-radius: 2px;
  transition: transform 0.1s ease;
}

/* PDF rendering canvas */
#pdf-canvas {
  display: block;
  border-radius: 2px;
}

/* Fabric.js overlay canvas wrapper */
#fabric-canvas-wrapper {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 10;
}

#fabric-canvas-wrapper .canvas-container {
  position: absolute !important;
  top: 0;
  left: 0;
}

/* Upper canvas styles from Fabric */
#fabric-canvas-wrapper .upper-canvas {
  cursor: default;
}

/* Text layer for search/selection (from PDF.js) */
.text-layer {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 5;
  opacity: 0.25;
  line-height: 1;
  pointer-events: none;
}

.text-layer span {
  position: absolute;
  white-space: pre;
  color: transparent;
  pointer-events: all;
}

.text-layer span::selection {
  background: rgba(99, 145, 255, 0.35);
}

.text-layer .highlight {
  background-color: rgba(251, 191, 36, 0.4);
  border-radius: 2px;
  margin: -1px;
  padding: 1px;
}

.text-layer .highlight.active {
  background-color: rgba(99, 145, 255, 0.5);
}

/* Empty state when no page */
.canvas-empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  color: var(--text-muted);
  padding: var(--space-16);
}

.canvas-empty svg {
  width: 64px;
  height: 64px;
  opacity: 0.2;
}

.canvas-empty p {
  font-size: var(--font-md);
  font-weight: 500;
}

/* Page shadow effect */
#canvas-container::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 2px;
  pointer-events: none;
  box-shadow: inset 0 0 0 1px rgba(0,0,0,0.1);
  z-index: 20;
}

/* Zoom indicator */
.zoom-indicator {
  position: absolute;
  bottom: var(--space-4);
  right: var(--space-4);
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-secondary);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  z-index: 25;
}

.zoom-indicator .tool-btn {
  width: 26px;
  height: 26px;
}

.zoom-indicator .tool-btn svg {
  width: 14px;
  height: 14px;
}

.zoom-indicator .zoom-value {
  font-size: var(--font-xs);
  font-weight: 600;
  color: var(--text-secondary);
  min-width: 36px;
  text-align: center;
}

/* Drawing cursor styles */
.canvas-area-draw { cursor: crosshair; }
.canvas-area-text { cursor: text; }
.canvas-area-move { cursor: grab; }
.canvas-area-moving { cursor: grabbing; }

/* Annotation highlight overlay effects */
.highlight-overlay {
  position: absolute;
  pointer-events: none;
  z-index: 8;
  mix-blend-mode: multiply;
  border-radius: 2px;
}

.highlight-yellow { background: rgba(255, 235, 59, 0.4); }
.highlight-green { background: rgba(76, 175, 80, 0.35); }
.highlight-blue { background: rgba(99, 145, 255, 0.35); }
.highlight-pink { background: rgba(233, 30, 99, 0.3); }