:root {
  --nb-bg: #0f172a;
  --nb-card: #111827;
  --nb-ink: #e5e7eb;
  --nb-accent: #60a5fa;
}

/* --- Base --- */
body {
  background: var(--nb-bg);
  color: var(--nb-ink);
  min-height: 100vh;
}

.nb-card {
  background: var(--nb-card);
  border-radius: 0.75rem;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.5);
}

.small-muted {
  color: #94a3b8;
  font-size: 0.85rem;
}

/* --- Palette: blocchi chiaramente trascinabili --- */
.palette-item {
  position: relative;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 10px 14px;
  border: 2px dashed rgba(255, 255, 255, 0.3);
  border-radius: 8px;
  cursor: grab;
  transition: background 0.2s ease, transform 0.1s ease, box-shadow 0.2s ease,
    border-color 0.2s ease;
  user-select: none;
}
.palette-item::before {
  content: "⋮⋮";
  font-size: 1rem;
  color: #9ca3af;
  margin-right: 4px;
  line-height: 1;
}
.palette-item:hover {
  background: rgba(96, 165, 250, 0.15); /* azzurro tenue */
  border-color: var(--nb-accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.45);
}
.palette-item::after {
  content: "⇅";
  position: absolute;
  top: 4px;
  right: 8px;
  font-size: 0.9rem;
  color: var(--nb-accent);
  opacity: 0;
  transition: opacity 0.2s ease;
}
.palette-item:hover::after {
  opacity: 1;
}
.palette-item:active {
  cursor: grabbing;
  transform: translateY(0);
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.3) inset;
}

/* --- Area drop & card layer --- */
.drop-area {
  min-height: 110px;
  padding: 10px;
  border: 1px dashed rgba(255, 255, 255, 0.3);
  border-radius: 8px;
  transition: background 0.2s ease, border-color 0.2s ease;
}
.drop-area.drop-hint {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--nb-accent);
}

.layer-card {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 10px;
  padding: 10px;
  transition: box-shadow 0.2s ease, transform 0.1s ease;
}
.layer-card.ghost {
  opacity: 0.5;
}
.layer-card:hover {
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.35);
  transform: translateY(-1px);
}

/* --- Slider manopole --- */
.form-range::-webkit-slider-thumb,
.form-range::-moz-range-thumb {
  background: var(--nb-accent);
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 2px solid #fff;
  box-shadow: 0 0 4px rgba(0, 0, 0, 0.6);
  appearance: none;
}

/* --- Visualizzazione rete --- */
.nn-vis-wrap {
  background: rgba(0, 0, 0, 0.25);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 12px;
}
.nn-node circle {
  fill: inherit;
  stroke: rgba(255, 255, 255, 0.95);
  stroke-width: 1.6;
}
.nn-node text {
  fill: #e5e7eb;
  font-weight: 600;
}
.nn-edge {
  opacity: 0.95;
}

/* --- Chart loss --- */
#lossChart {
  background: #0f172a;
  border-radius: 8px;
  padding: 4px;
}

/* --- Drop CSV --- */
.drop-zone {
  border: 2px dashed rgba(255, 255, 255, 0.3);
  padding: 20px;
  text-align: center;
  border-radius: 8px;
  transition: background 0.2s ease, border-color 0.2s ease;
}
.drop-zone.dragover {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--nb-accent);
}

/* --- Popup --- */

.popover {
  z-index: 2000;
}

/* Popover dark leggibile (Bootstrap 5.3+) */
.popover-dark {
  /* colori & aspetto */
  --bs-popover-bg: #0f172a; /* sfondo */
  --bs-popover-border-color: rgba(255, 255, 255, 0.3);
  --bs-popover-body-color: #ffffff; /* testo corpo */
  --bs-popover-header-bg: #0f172a; /* header */
  --bs-popover-header-color: #ffffff; /* testo header */
  --bs-popover-arrow-border: #0f172a; /* freccia/bordo */
  --bs-popover-arrow-color: #0f172a;

  --bs-popover-border-radius: 10px;
  --bs-popover-box-shadow: 0 6px 20px rgba(0, 0, 0, 0.5);
  max-width: 300px;
}
/* --- Fix header popover dark --- */
.popover.popover-dark {
  /* rinforzo colori base */
  --bs-popover-bg: #0f172a;
  --bs-popover-border-color: rgba(255, 255, 255, 0.3);
  --bs-popover-body-color: #ffffff;

  /* header ben contrastato */
  --bs-popover-header-bg: #0b1220; /* più scuro dell'area body */
  --bs-popover-header-color: #ffffff;
  --bs-popover-header-border-color: rgba(255, 255, 255, 0.3);

  /* freccia dello stesso colore dello sfondo */
  --bs-popover-arrow-color: #0f172a;
  --bs-popover-arrow-border: #0f172a;
}

/* stile dell'header (se alcune versioni di Bootstrap ignorano le vars) */
.popover-dark .popover-header {
  background: #0b1220 !important;
  color: #ffffff !important;
  border-bottom: 1px solid rgba(255, 255, 255, 0.3) !important;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.2px;
}

/* facoltativo: rendi il titolo un po' più leggibile anche su retina */
.popover-dark .popover-header,
.popover-dark .popover-body {
  text-shadow: 0 0 0.01px rgba(255, 255, 255, 0.5);
}