/* Tree Canvas */
.tree-canvas {
  width: 100%; height: 100%; overflow: auto; padding: 40px;
  position: relative;
  cursor: grab; user-select: none; overscroll-behavior: none; touch-action: none;
  will-change: transform;
}
.tree-canvas.dragging { cursor: grabbing; }
.tree-inner {
  position: relative;
  min-width: max-content;
  width: max-content;
  transform-origin: 0 0;
}

/* Tree Nodes */
.tree-node {
  background:
    linear-gradient(135deg, rgba(82,183,136,0.05) 0%, transparent 50%),
    rgba(255,255,255,0.06);
  border-radius: var(--radius); padding: 18px 24px; cursor: pointer;
  transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition); position: relative;
  min-width: 180px; width: fit-content; max-width: min(32vw, 560px);
  overflow-wrap: break-word; word-break: break-word;
  min-width: 0;
  overflow: visible;
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.06),
    0 0 0 1px rgba(27,67,50,0.7),
    0 2px 12px rgba(0,0,0,0.15);
  contain: layout style;
}

/* Non-flippable hover */
.tree-node:not(.flippable):hover {
  background:
    linear-gradient(135deg, rgba(82,183,136,0.1) 0%, transparent 50%),
    rgba(255,255,255,0.08);
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.08),
    0 0 0 1px var(--border-active),
    0 0 30px var(--primary-glow),
    0 4px 20px rgba(0,0,0,0.2);
  transform: translateY(-3px);
}

/* Flippable: card visuals live on flip-inner so border/background flips with content */
.tree-node.flippable {
  background: transparent;
  padding: 0;
  box-shadow: none;
  margin-bottom: 4px;
}
.tree-node.flippable > .flip-inner {
  background:
    linear-gradient(135deg, rgba(82,183,136,0.05) 0%, transparent 50%),
    rgba(255,255,255,0.06);
  border-radius: var(--radius);
  width: 100%; min-width: 180px;
  border: 1px solid rgba(27,67,50,0.7);
  overflow-wrap: break-word; word-break: break-word;
}
.tree-node.flippable:hover {
  transform: translateY(-3px);
}
.tree-node.flippable:hover > .flip-inner {
  background:
    linear-gradient(135deg, rgba(82,183,136,0.1) 0%, transparent 50%),
    rgba(255,255,255,0.08);
  border-color: var(--border-active);
  box-shadow: 0 0 30px var(--primary-glow), 0 4px 20px rgba(0,0,0,0.2);
  transition: background var(--transition), border-color var(--transition), box-shadow var(--transition);
}
.node-scroll { max-height: 45vh; overflow-y: auto; scrollbar-width: thin; }
.node-title {
  font-size: 17px; font-weight: 700; color: var(--primary); margin-bottom: 10px;
  line-height: 1.4; letter-spacing: 0.5px;
}
.tree-node .node-front { font-size: 15px; line-height: 1.8; margin-bottom: 14px; color: var(--text); }
.tree-node .node-meta { font-size: 13px; color: var(--text3); display: flex; gap: 18px; }
.tree-node .node-meta span { display: flex; align-items: center; gap: 3px; }
.tree-node .node-back-content { font-size: 13px; line-height: 1.6; color: var(--text2); font-style: italic; padding: 10px 12px; background: rgba(0,0,0,0.18); border-radius: var(--radius-sm); }
.tree-node .node-signature { font-size: 11px; color: var(--text3); font-style: normal; }
.tree-node .root-badge, .tree-node .ai-badge {
  font-size: 10px; padding: 3px 10px; border-radius: 4px; margin-left: 6px;
  background: var(--primary-dim); color: var(--primary);
  vertical-align: middle; white-space: nowrap;
}
.root-badge { background: var(--primary); color: var(--bg-deep); }
.ai-badge { background: rgba(157,78,221,0.25); color: #c77dff; border: 1px solid rgba(157,78,221,0.15); }

/* Node flash animation (search focus) */
@keyframes node-flash {
  0%, 100% { border-color: var(--border); box-shadow: none; }
  50% { border-color: var(--primary); box-shadow: 0 0 20px var(--primary-glow); }
}
.tree-node.flash { animation: node-flash 1s ease; }
.tree-node.highlighted {
  box-shadow:
    inset 0 1px 0 rgba(82,183,136,0.25),
    0 0 0 2px var(--primary),
    0 0 40px var(--primary-glow),
    0 4px 24px rgba(0,0,0,0.3);
  transform: translateY(-2px);
}
.tree-node.highlighted .node-title {
  color: var(--primary-light);
}

/* Tree Layout */
.tree-horizontal {
  display: flex; align-items: flex-start; gap: 40px;
  position: relative;
  flex-shrink: 0;
}
.tree-children {
  display: flex; flex-direction: column; gap: 28px;
  position: relative;
  flex-shrink: 0;
}

/* SVG Bezier curve connectors */
.tree-svg {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  pointer-events: none;
  overflow: visible;
  z-index: 0;
}
.tree-svg path {
  fill: none;
  stroke: rgba(107,66,38,0.45);
  stroke-width: 2.5;
  stroke-linecap: round;
  filter: drop-shadow(0 0 3px rgba(107,66,38,0.3));
}

/* Card Flip (simple fade) */
.flip-inner {
  display: grid;
  align-items: start;
}
.flip-front, .flip-back { grid-area: 1 / 1 / 2 / 2; }
.flip-front { padding: 16px 38px; opacity: 1; transition: opacity 0.3s ease; }
.flip-back {
  padding: 16px 14px;
  opacity: 0; pointer-events: none;
}
.flip-inner.flipped .flip-front { opacity: 0; pointer-events: none; transition: opacity 0s; }
.flip-inner.flipped .flip-back { opacity: 1; pointer-events: auto; transition: opacity 0.5s ease; }
.tree-node.flippable { position: relative; perspective: 1000px; }
.btn-flip {
  position: absolute; right: -22px; top: 14px; z-index: 5;
  cursor: pointer; line-height: 1; padding: 0; border: none; background: none;
  display: flex; align-items: center; justify-content: center;
  transition: all 0.3s ease; outline: none;
  color: rgba(160,255,170,0.85); opacity: 0.8;
  filter: drop-shadow(0 1px 3px rgba(0,0,0,0.3));
}
.btn-flip:hover { opacity: 1; color: rgba(160,255,170,0.95); transform: scale(1.15); filter: drop-shadow(0 0 10px rgba(100,220,120,0.35)); }
.btn-flip:active { transform: scale(0.9); color: rgba(160,255,170,0.95); }
.btn-flip svg { transition: transform 0.4s ease, color 0.3s ease; display: block; }
.flip-container .flip-inner.flipped ~ .btn-flip { opacity: 0.6; color: rgba(190,210,90,0.55); }
.flip-container .flip-inner.flipped ~ .btn-flip svg { transform: rotate(90deg); }
.flip-back-footer {
  display: flex; justify-content: space-between; align-items: center;
  margin-top: 12px;
}
.btn-flip-back {
  display: inline-block; padding: 5px 12px;
  font-size: 11px; color: var(--text3); cursor: pointer;
  border-radius: 4px; border: 1px solid var(--border); background: transparent;
  transition: all var(--transition-fast); font-family: inherit;
}
.btn-flip-back:hover { color: var(--primary); border-color: var(--primary); background: rgba(82,183,136,0.06); }
.btn-read {
  position: absolute; left: 50%; transform: translateX(-50%);
  top: 100%; margin-top: 2px; z-index: 4;
  cursor: pointer; line-height: 1; padding: 4px 8px; border: none; background: none;
  display: none; align-items: center; justify-content: center;
  transition: opacity 0.3s ease; outline: none;
  font-size: 18px; color: #7ecf8a;
  filter: drop-shadow(0 1px 3px rgba(0,0,0,0.3));
}
.btn-read:hover { opacity: 0.8; }
.btn-read:active { opacity: 0.6; }

/* Node detail flip */
.node-detail .back-reveal { margin-bottom: 12px; }
.node-detail .back-reveal .btn-flip-back { display: none; }
.node-detail .flip-inner { transform: none !important; transform-style: flat; transition: none; position: static; }
.node-detail .flip-back { transform: translateY(8px); transition: opacity 0.4s ease, transform 0.4s ease; pointer-events: auto; overflow: visible; }
.node-detail .flip-inner.flipped { transform: none; filter: none; }
.node-detail .flip-inner.flipped .flip-back { transform: translateY(0); opacity: 1; }
.node-detail .back-reveal .btn-flip-trigger {
  background: rgba(82,183,136,0.08); border: 1px solid var(--border-active);
  border-radius: var(--radius-sm); cursor: pointer;
  font-size: 12px; color: var(--primary); padding: 8px 18px;
  transition: all var(--transition-fast); font-family: inherit;
  font-weight: 500;
}
.node-detail .back-reveal .btn-flip-trigger:hover { background: rgba(82,183,136,0.15); border-color: var(--primary); box-shadow: 0 0 16px var(--primary-glow); }
.node-detail .node-title { font-size: 20px; margin-bottom: 12px; }
.node-detail .front { font-size: 16px; line-height: 1.7; margin-bottom: 14px; overflow-wrap: break-word; word-break: break-word; }
.node-detail .back { font-size: 13px; color: var(--text2); font-style: italic; padding: 16px 16px 12px; background: rgba(0,0,0,0.25); border-radius: var(--radius-sm); overflow-wrap: break-word; word-break: break-word; }

/* Lazy Rendering Placeholder */
.tree-node-lazy .lazy-placeholder {
  animation: lazyPulse 2s ease-in-out infinite;
}
@keyframes lazyPulse {
  0%, 100% { opacity: 0.3; }
  50% { opacity: 0.6; }
}

/* Story Zone */
.zone-list {
  max-height: 50vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 12px;
}
.zone-item {
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  cursor: pointer;
  transition: all var(--transition-fast);
}
.zone-item:hover {
  background: rgba(82,183,136,0.06);
  border-color: var(--border-active);
  transform: translateX(4px);
}
.zone-item-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}
.zone-item-info {
  min-width: 0;
  flex: 1;
}
.zone-delete-btn {
  flex-shrink: 0;
}
.zone-item-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
}
.zone-item-meta {
  font-size: 12px;
  color: var(--text3);
}

/* Mobile responsive */
@media (max-width: 768px) {
  .tree-canvas { padding: 12px; }
  .tree-canvas::-webkit-scrollbar { display: none; }
  .tree-canvas { -ms-overflow-style: none; scrollbar-width: none; }
  .tree-horizontal { gap: 24px; }
  .tree-children { gap: 24px; }
  .tree-node { padding: 8px 10px; min-width: 120px; max-width: min(85vw, 320px); }
  .tree-node.flippable > .flip-inner { min-width: 140px; max-width: min(85vw, 320px); }
  .flip-front { padding: 8px 28px; }
  .flip-back { padding: 8px 10px; }
  .btn-flip { right: -20px; top: 6px; opacity: 0.6; }
  .btn-read { display: flex; opacity: 0.6; }
  .node-title { font-size: 13px; }
  .tree-node .node-front { font-size: 12px; }
  .tree-node .node-meta { font-size: 10px; gap: 8px; }
  .node-scroll { max-height: 60vh; }
  .stories-layout { flex-direction: column; }
  .stories-left { flex: none; width: 100%; border-right: none; border-bottom: 1px solid var(--border); padding-right: 0; padding-bottom: 12px; }
}

*:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; border-radius: 4px; }