/* ===== canvas.css =====
   Mal-Bühne, A4-Papier, Overlays
   FIX: .stage mit bestimmter Größe (vorher 0×0-Kollaps)
   Overlay-Deckkraft via --overlay-opacity (Slider in main.js) */

.canvas-area {
  flex: 1;
  min-width: 0;
  display: flex;
  overflow: auto;
  position: relative;
  padding: 24px;
}

.stage {
  position: relative;
  width: 100%;
  height: 100%;
  display: flex;
  flex-shrink: 0;
}

.paper-wrap {
  position: relative;
  margin: auto;
  flex-shrink: 0;
  --avail-h: calc(100dvh - var(--header-h) - 48px);
  width: min(100%, calc(var(--avail-h) * 210 / 297), 600px);
  min-width: 260px;
  aspect-ratio: 210 / 297;
  transition: transform var(--duration-slow, 0.5s) var(--ease, ease),
              box-shadow var(--duration-slow, 0.5s) var(--ease, ease);
}
.paper-wrap:hover { transform: scale(1.005); }

.paper {
  position: absolute;
  inset: 0;
  background: #ffffff;
  border: 1px solid rgba(0, 0, 0, 0.06);
  border-radius: var(--radius-lg, 20px);
  box-shadow: var(--shadow-lg, 0 16px 48px rgba(0,0,0,0.12)),
              0 0 0 1px rgba(255,255,255,0.6) inset;
  overflow: hidden;
  z-index: 1;
}
[data-theme="dark"] .paper {
  background: oklch(0.96 0.003 90);
  border-color: rgba(255,255,255,0.06);
}

#draw-canvas {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  touch-action: none;
  z-index: 2;
  cursor: none;
}

#overlay-img {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  object-fit: contain;
  pointer-events: none;
  opacity: var(--overlay-opacity, 0.9);
  z-index: 3;
  mix-blend-mode: multiply;
  transition: opacity 0.3s ease;
}
#overlay-img.hidden { opacity: 0; }

/* Washi-Tape: ausgemustert – falls im Markup vorhanden, unsichtbar */
.washi { display: none; }

/* Cursor-Ring */
.cursor-ring {
  position: fixed;
  border-radius: 50%;
  border: 1.5px solid oklch(0.25 0.05 285 / 0.5);
  pointer-events: none;
  z-index: 9999;
  transform: translate(-50%, -50%);
  transition: width 0.15s ease, height 0.15s ease;
  mix-blend-mode: difference;
  display: none;
}
.canvas-area:hover .cursor-ring { display: block; }

@media (max-width: 1100px) {
  .paper-wrap { width: min(100%, calc(var(--avail-h) * 210 / 297), 500px); }
}
@media (max-width: 768px) {
  .paper-wrap { --avail-h: calc(100dvh - var(--header-h) - 130px); }
  .canvas-area { padding: 12px; }
}
@media (max-width: 480px) {
  .paper-wrap { width: min(100%, calc(var(--avail-h) * 210 / 297), 300px); }
  .canvas-area { padding: 8px; }
}
@media (prefers-reduced-motion: reduce) {
  .paper-wrap { transition: none !important; }
  .paper-wrap:hover { transform: none; }
}