.nav-btn {
  color: #64748b;
  transition: all 0.15s ease;
}
.nav-btn:hover {
  background-color: #f1f5f9;
}
.nav-btn.active-tab {
  background-color: #eef2ff;
  color: #4338ca;
}
#flash-card {
  transition: transform 0.15s ease;
}

/* ===================== Whiteboard / Moodboard ===================== */
.wb-tool-btn {
  color: #64748b;
}
.wb-tool-btn.active-tool {
  background-color: #eef2ff;
  color: #4338ca;
}
#wb-canvas-wrap, #mb-canvas-wrap {
  touch-action: none;
}
#wb-canvas-wrap.panning, #mb-canvas-wrap.panning {
  cursor: grab;
}
.mb-comment-badge {
  position: absolute;
  background: #7c3aed;
  color: white;
  border-radius: 999px;
  font-size: 10px;
  font-weight: 700;
  min-width: 18px;
  height: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 4px;
  pointer-events: none;
  box-shadow: 0 1px 3px rgba(0,0,0,0.3);
  z-index: 5;
}
.mb-comment-item {
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  padding: 6px 8px;
  font-size: 12px;
}
.mb-comment-item .mb-comment-time {
  font-size: 10px;
  color: #94a3b8;
}