.demo-section {
  background: var(--white);
  border-top: 1px solid var(--line);
}

.demo-intro {
  text-align: center;
  max-width: 1500px;
  margin: 0 auto 48px;
}

/* Upload Zone */
.upload-zone {
  border: 2px dashed rgba(4, 124, 118, 0.4);
  border-radius: 12px;
  padding: 48px 24px;
  text-align: center;
  background: var(--mist);
  cursor: pointer;
  transition: all 0.2s ease;
  margin-bottom: 24px;
}

.upload-zone:hover,
.upload-zone.drag-over {
  background: #d4e8de;
  border-color: var(--teal);
  transform: translateY(-2px);
}

.upload-icon svg {
  width: 48px;
  height: 48px;
  stroke: var(--teal);
  stroke-width: 1.5;
  fill: none;
  margin-bottom: 16px;
}

.upload-zone h3 { margin: 0 0 8px; font-size: 1.35rem; color: var(--ink); }
.upload-zone p { margin: 0; color: var(--ink-soft); }
.upload-zone .hint { font-size: 0.85rem; margin-top: 16px; opacity: 0.7; }

/* Controls */
.demo-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 32px;
  justify-content: center;
  padding: 24px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 8px;
  margin-bottom: 24px;
}

.demo-controls label {
  display: flex;
  flex-direction: column;
  align-items: center;
  font-size: 0.9rem;
  color: var(--ink-soft);
  gap: 12px;
  font-weight: 600;
}

.demo-controls input[type="range"] {
  accent-color: var(--teal);
  width: 140px;
  cursor: pointer;
  height: 6px;
  padding: 0;
}

.ctrl-val {
  font-weight: 800;
  color: var(--teal);
  font-family: 'DM Mono', monospace;
}

.roi-control-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
}

.roi-toggle { flex-direction: row !important; gap: 8px !important; cursor: pointer; }
.roi-toggle input { width: 18px; height: 18px; accent-color: var(--teal); cursor: pointer; }

.roi-btn {
  min-height: 34px;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 0 12px;
  background: var(--white);
  color: var(--ink);
  font-weight: 800;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.roi-btn:hover:not(:disabled),
.roi-btn:focus-visible:not(:disabled) {
  background: rgba(4, 124, 118, 0.08);
  border-color: var(--teal);
  color: var(--teal);
}
.roi-btn:disabled { cursor: not-allowed; opacity: 0.48; }

.roi-readout {
  min-width: 86px;
  color: var(--teal);
  font-family: 'DM Mono', monospace;
  font-size: 0.82rem;
  font-weight: 800;
  text-align: center;
}

/* Grid & Canvases */
.demo-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; margin-bottom: 24px; }
.demo-grid.roi-pending { grid-template-columns: minmax(0, 760px); justify-content: center; }

.demo-panel {
  background: var(--ink);
  border-radius: 12px;
  overflow: hidden;
  position: relative;
  aspect-ratio: 16 / 9;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  box-shadow: 0 14px 40px rgba(20, 32, 31, 0.12);
}

.demo-panel-label {
  position: absolute;
  top: 16px;
  left: 16px;
  background: rgba(20, 32, 31, 0.65);
  color: var(--white);
  padding: 6px 12px;
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 700;
  z-index: 10;
  backdrop-filter: blur(8px);
}

.demo-panel canvas { width: 100% !important; height: 100% !important; object-fit: contain; display: none; }
.roi-overlay { position: absolute; inset: 0; z-index: 8; display: none; cursor: crosshair; touch-action: none; }
.roi-overlay.active { display: block; }
.roi-overlay.selecting { background: rgba(4, 124, 118, 0.08); }
.roi-selection {
  position: absolute; display: none; border: 2px solid #93f2e6; border-radius: 4px; background: rgba(147, 242, 230, 0.12);
  box-shadow: 0 0 0 9999px rgba(20, 32, 31, 0.26), 0 0 0 1px rgba(20, 32, 31, 0.35);
}
.roi-overlay.has-selection .roi-selection { display: block; }

.demo-placeholder { display: flex; flex-direction: column; align-items: center; gap: 12px; color: rgba(255, 253, 248, 0.5); font-weight: 600; }
.demo-placeholder svg { width: 42px; height: 42px; stroke: rgba(255, 253, 248, 0.5); stroke-width: 1.5; fill: none; }
.demo-status { text-align: center; font-weight: 600; color: var(--teal); min-height: 24px; margin-bottom: 16px; }

#flow-legend { display: none; justify-content: center; align-items: center; flex-wrap: wrap; gap: 16px; font-size: 0.9rem; color: var(--ink-soft); background: var(--paper); padding: 16px; border-radius: 8px; border: 1px solid var(--line); }
#flow-legend.visible { display: flex; }
.legend-item { display: flex; align-items: center; gap: 8px; font-weight: 700; color: var(--ink); }
.legend-dot { width: 12px; height: 12px; border-radius: 50%; display: inline-block; box-shadow: inset 0 0 0 1px rgba(0,0,0,0.1); }

/* Video Controls Tracking */
.video-controls { display: none; flex-direction: column; gap: 10px; margin-top: 20px; padding: 14px 18px; background: var(--paper); border: 1px solid var(--line); border-radius: 10px; }
.vc-seek-row { display: flex; align-items: center; gap: 12px; }
.vc-seek-row input[type="range"] { flex: 1; cursor: pointer; accent-color: var(--teal); }
#time-display { font-family: 'DM Mono', monospace; font-size: 0.85rem; color: var(--teal); white-space: nowrap; min-width: 88px; text-align: right; }
.vc-btn-row { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 10px; }
.vc-left { display: flex; align-items: center; gap: 8px; }
.vc-right { display: flex; align-items: center; gap: 10px; }
.vc-btn { display: inline-flex; align-items: center; justify-content: center; width: 38px; height: 38px; padding: 0; border: 1px solid var(--line); border-radius: 8px; background: var(--white); color: var(--ink); cursor: pointer; transition: background 0.15s, color 0.15s, border-color 0.15s; }
.vc-btn svg { width: 16px; height: 16px; }
.vc-btn:hover { background: rgba(4, 124, 118, 0.08); color: var(--teal); border-color: var(--teal); }
.vc-btn-play { width: 44px; height: 44px; }
.vc-btn-play svg { width: 18px; height: 18px; }
.vc-btn-active { background: rgba(4, 124, 118, 0.12); color: var(--teal); border-color: var(--teal); }
.vc-speed-label { font-family: 'DM Mono', monospace; font-size: 0.75rem; color: var(--ink-soft); letter-spacing: 0.06em; text-transform: uppercase; }
.vc-speed-group { display: flex; gap: 4px; }
.vc-speed-btn { font-family: 'DM Mono', monospace; font-size: 0.75rem; padding: 5px 9px; border: 1px solid var(--line); border-radius: 6px; background: var(--white); color: var(--ink-soft); cursor: pointer; transition: background 0.12s, color 0.12s, border-color 0.12s; white-space: nowrap; }
.vc-speed-btn:hover { background: rgba(4, 124, 118, 0.08); color: var(--teal); border-color: var(--teal); }
.vc-speed-active { background: rgba(4, 124, 118, 0.15) !important; color: var(--teal) !important; border-color: var(--teal) !important; }

@media (max-width: 520px) {
  .vc-speed-label { display: none; }
  .vc-speed-btn { padding: 5px 6px; font-size: 0.7rem; }
}