.layout-grid {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
  margin-top: var(--spacing-md);
}

@media (min-width: 900px) {
  .layout-grid {
    flex-direction: row;
    align-items: stretch;
  }
}

.controls-sidebar {
  flex: 0 0 320px;
}

.control-group {
  margin-bottom: var(--spacing-md);
}

.control-group label {
  display: block;
  font-weight: 500;
  margin-bottom: 4px;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.control-group span {
  font-weight: bold;
  color: var(--text-primary);
}

.select-input, input[type="range"] {
  width: 100%;
  padding: 0.5rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-color);
  font-family: inherit;
  font-size: 0.95rem;
  color: var(--text-primary);
  outline: none;
}

.select-input:focus {
  border-color: var(--text-primary);
}

input[type="range"] {
  padding: 0;
  accent-color: var(--text-primary);
}

.actions {
  display: flex;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-lg);
}

.btn-sm {
  padding: 0.5rem;
  font-size: 0.85rem;
  flex: 1;
}

.flex-visualizer {
  flex: 1;
  min-height: 500px;
  display: flex;
}

.flex-container {
  display: flex;
  width: 100%;
  background: var(--bg-color);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  gap: 16px; /* default */
  /* This guarantees min-height to show align-items clearly */
  min-height: 100%; 
  transition: all 0.3s ease;
}

.flex-item {
  background: var(--text-primary);
  color: var(--surface);
  padding: 1rem 1.5rem;
  font-weight: 700;
  font-size: 1.2rem;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  /* subtle border so they don't blend if they touch */
  border: 1px solid rgba(0,0,0,0.1);
}

/* Give them varied sizes so stretch/baseline/etc are obvious */
.flex-item:nth-child(even) {
  padding: 2rem 1.5rem;
  font-size: 1.5rem;
  background: var(--primary);
  color: var(--text-primary);
}

.flex-item:nth-child(3n) {
  padding: 1.5rem 2.5rem;
}