/* ============================================================
   Knowledge Graph — Obsidian-inspired graph view
   ============================================================ */

.kg-view {
  display: flex;
  flex-direction: column;
  height: calc(100vh - var(--navbar-height));
  max-height: calc(100dvh - var(--navbar-height));
  overflow: hidden;
  background: var(--color-bg);
}

.kg-header {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 16px;
  padding: 16px 20px 12px;
  flex-shrink: 0;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg-elevated);
}

.kg-header__back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 12px;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: background-color var(--duration-fast) var(--ease-out);
}

.kg-header__back:hover {
  background: var(--color-bg-hover);
  color: var(--color-text-primary);
}

.kg-header__center {
  text-align: center;
  min-width: 0;
}

.kg-header__breadcrumb {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
  color: var(--color-accent);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.kg-header__title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  letter-spacing: var(--letter-spacing-tight);
}

.kg-header__stats {
  display: flex;
  gap: 14px;
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
}

.kg-stat strong {
  color: var(--color-text-primary);
  font-weight: var(--font-weight-semibold);
}

.kg-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 20px;
  flex-shrink: 0;
  background: var(--color-bg-elevated);
  border-bottom: 1px solid var(--color-border);
}

.kg-search {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 1;
  max-width: 320px;
  padding: 0 12px;
  height: 36px;
  background: var(--color-bg-subtle);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.kg-search__icon {
  color: var(--color-text-tertiary);
  flex-shrink: 0;
}

.kg-search__input {
  flex: 1;
  min-width: 0;
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
}

.kg-search__input::placeholder {
  color: var(--color-text-tertiary);
}

.kg-zoom-controls {
  display: flex;
  gap: 4px;
}

.kg-zoom-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  background: var(--color-bg-subtle);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  transition: background-color var(--duration-fast) var(--ease-out);
}

.kg-zoom-btn:hover {
  background: var(--color-bg-hover);
  color: var(--color-text-primary);
}

.kg-canvas-wrap {
  position: relative;
  flex: 1;
  min-height: 0;
  overflow: hidden;
  cursor: grab;
  background:
    radial-gradient(circle at 50% 50%, color-mix(in srgb, var(--color-accent) 4%, var(--color-bg)) 0%, var(--color-bg) 70%);
}

.kg-canvas-wrap.is-panning {
  cursor: grabbing;
}

.kg-canvas-wrap.is-dragging-node {
  cursor: crosshair;
}

.kg-svg {
  display: block;
  width: 100%;
  height: 100%;
  touch-action: none;
}

.kg-svg__bg {
  fill: transparent;
}

.kg-edge {
  stroke: var(--color-border-strong);
  stroke-width: 1;
  stroke-opacity: 0.35;
  transition: stroke-opacity var(--duration-fast) var(--ease-out),
              stroke-width var(--duration-fast) var(--ease-out);
}

.kg-edge--wiki {
  stroke-opacity: 0.5;
}

.kg-edge.is-highlighted {
  stroke: var(--color-accent);
  stroke-opacity: 0.85;
  stroke-width: 1.5;
}

.kg-edge.is-dimmed {
  stroke-opacity: 0.06;
}

.kg-node {
  cursor: pointer;
}

.kg-node__circle {
  fill: var(--node-color, var(--color-accent));
  stroke: var(--color-bg-elevated);
  stroke-width: 2;
  transition: r var(--duration-fast) var(--ease-out),
              fill-opacity var(--duration-fast) var(--ease-out),
              stroke-width var(--duration-fast) var(--ease-out);
}

.kg-node__label {
  font-size: 11px;
  font-weight: var(--font-weight-medium);
  fill: var(--color-text-secondary);
  pointer-events: none;
  user-select: none;
  opacity: 0;
  transition: opacity var(--duration-fast) var(--ease-out);
}

.kg-node.is-highlighted .kg-node__circle {
  stroke-width: 3;
  stroke: var(--color-accent);
  filter: drop-shadow(0 0 6px color-mix(in srgb, var(--color-accent) 50%, transparent));
}

.kg-node.is-search-match .kg-node__circle {
  stroke: var(--color-accent);
  stroke-width: 2.5;
}

.kg-node.is-dimmed .kg-node__circle {
  fill-opacity: 0.12;
}

.kg-node.is-dimmed .kg-node__label {
  opacity: 0 !important;
}

.kg-node:hover .kg-node__label,
.kg-node.is-highlighted .kg-node__label,
.kg-node.is-search-match .kg-node__label {
  opacity: 1;
}

.kg-node:hover .kg-node__circle {
  stroke-width: 2.5;
}

.kg-empty {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 24px;
  text-align: center;
  pointer-events: none;
}

.kg-empty[hidden] {
  display: none;
}

.kg-empty__title {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: 8px;
}

.kg-empty__text {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  max-width: 360px;
  line-height: var(--line-height-relaxed);
}

.kg-empty kbd {
  padding: 2px 6px;
  font-family: inherit;
  font-size: var(--font-size-xs);
  background: var(--color-bg-subtle);
  border: 1px solid var(--color-border);
  border-radius: 4px;
}

.kg-hint {
  position: absolute;
  bottom: 16px;
  left: 50%;
  transform: translateX(-50%);
  padding: 6px 14px;
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  background: color-mix(in srgb, var(--color-bg-elevated) 85%, transparent);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  pointer-events: none;
  opacity: 0.85;
}

@media (max-width: 768px) {
  .kg-header {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto auto;
    text-align: center;
  }

  .kg-header__back {
    justify-self: start;
  }

  .kg-header__stats {
    justify-content: center;
  }

  .kg-header__back span {
    display: none;
  }

  .kg-hint {
    display: none;
  }
}