/* ── Panel de investigación ───────────────────────────────────────────────── */
#research-section {
  padding: 0;
}

#research-section h2 {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .9px;
  color: var(--text-muted);
  margin: 0 0 6px;
}

.research-subtitle {
  font-size: .75rem;
  color: var(--text-muted);
  margin: 0 0 12px;
  line-height: 1.4;
}

/* ── Grid del árbol ───────────────────────────────────────────────────────── */
.research-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}

/* ── Separador de fila ────────────────────────────────────────────────────── */
.research-row-label {
  grid-column: 1 / -1;
  font-size: .65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .6px;
  color: var(--text-muted);
  padding: 8px 0 2px;
  border-top: 1px solid var(--border);
  opacity: .6;
}

.research-row-label:first-child {
  border-top: none;
  padding-top: 0;
}

/* ── Tarjeta de nodo ──────────────────────────────────────────────────────── */
.research-node {
  background: var(--bg-card);
  border: 2px solid var(--border);
  border-radius: 8px;
  padding: 10px;
  display: flex;
  flex-direction: column;
  gap: 5px;
  cursor: default;
  transition: border-color .15s, transform .1s, box-shadow .15s;
  position: relative;
}

/* Disponible pero sin fondos */
.research-node.available {
  border-color: #3b82f6;
  cursor: pointer;
}

.research-node.available:hover {
  border-color: #60a5fa;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(59, 130, 246, .2);
}

/* Con fondos suficientes — pulsante verde */
.research-node.can-afford {
  border-color: #10b981;
  cursor: pointer;
  animation: rn-pulse 2s ease-in-out infinite;
}

@keyframes rn-pulse {
  0%, 100% { box-shadow: 0 0 0 0   rgba(16, 185, 129, .5); }
  50%       { box-shadow: 0 0 0 5px rgba(16, 185, 129, 0);  }
}

.research-node.can-afford:hover {
  border-color: #34d399;
  transform: translateY(-2px);
  box-shadow: 0 4px 14px rgba(16, 185, 129, .3);
}

/* Ya investigado */
.research-node.done {
  border-color: #d1fae5;
  background: #f0fdf4;
  cursor: default;
}

/* Bloqueado */
.research-node.locked {
  opacity: .45;
  filter: grayscale(.5);
  cursor: not-allowed;
}

/* ── Contenido de la tarjeta ──────────────────────────────────────────────── */
.rn-header {
  display: flex;
  align-items: center;
  gap: 7px;
}

.rn-icon {
  font-size: 1.3rem;
  line-height: 1;
  flex-shrink: 0;
}

.rn-name {
  font-size: .8rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.2;
}

.rn-desc {
  font-size: .72rem;
  color: var(--text-muted);
  line-height: 1.4;
}

/* Check cuando está hecho */
.rn-done-check {
  position: absolute;
  top: 8px;
  right: 8px;
  font-size: .85rem;
  color: #10b981;
  font-weight: 700;
}

/* ── Costes ───────────────────────────────────────────────────────────────── */
.rn-cost {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  margin-top: 2px;
  padding-top: 6px;
  border-top: 1px solid var(--border);
}

.rn-cost-item {
  display: inline-flex;
  align-items: center;
  gap: 3px;
  background: rgba(0,0,0,.05);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 6px;
  font-size: .72rem;
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
}

/* Rojo si no alcanza */
.rn-cost-item.missing {
  color: #dc2626;
  background: #fef2f2;
  border-color: #fca5a5;
}

/* ── Responsive ───────────────────────────────────────────────────────────── */
@media (max-width: 900px) {
  .research-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 640px) {
  .research-grid { grid-template-columns: repeat(2, 1fr); gap: 6px; }
  .research-node { padding: 8px; }
  .rn-icon  { font-size: 1.1rem; }
  .rn-name  { font-size: .74rem; }
  .rn-desc  { font-size: .67rem; }
  .rn-cost-item { font-size: .66rem; padding: 1px 5px; }
}