.cardbackground {
  display: flex;
  align-items: center;
  justify-content: center;
}

.viz-canvas {
  width: 100%;
  height: 400px;
  display: block;
}

.card2 {

}

.nb-audio-ui {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.nb-audio-label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  opacity: 0.6;
}

.nb-audio-ui input[type="file"] {
  font-size: 12px;
}

.nb-audio-ui button {
  padding: 6px 0;
  font-size: 13px;
  border: 1px solid currentColor;
  background: transparent;
  cursor: pointer;
}

/* Stack the two cards ONLY on phone widths */
@media (max-width: 576px) {
  .nb-stack-row {
    flex-direction: column !important;
  }

  .nb-stack-row > [class^="col-"],
  .nb-stack-row > [class*=" col-"] {
    width: 100% !important;
    max-width: 100% !important;
    flex: 0 0 100% !important;
  }

  .nb-stack-row > [class^="col-"]:not(:last-child),
  .nb-stack-row > [class*=" col-"]:not(:last-child) {
    margin-bottom: 12px;
  }

  .viz-canvas {
    height: 320px; /* optional, helps on phones */
  }
}