/* Vertical nav sidebar */
.app-nav {
  align-items: center;
  background: var(--bg-panel);
  border-right: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-xs);
  width: 3.5rem;
}

.app-nav__item {
  align-items: center;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  display: inline-flex;
  height: var(--control-h-lg);
  justify-content: center;
  position: relative;
  transition: background-color var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
  width: var(--control-h-lg);
}

/* Tooltip on hover — uses aria-label as content */
.app-nav__item::after {
  background: var(--neutral-800);
  border-radius: var(--radius-xs);
  color: var(--neutral-100);
  content: attr(aria-label);
  font-size: var(--text-xs);
  left: calc(100% + var(--space-xs));
  opacity: 0;
  padding: var(--space-2xs) var(--space-xs);
  pointer-events: none;
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  transition: opacity var(--transition-fast);
  white-space: nowrap;
}

.app-nav__item:hover::after {
  opacity: 1;
}

.app-nav__item:hover,
.app-nav__item.is-active {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.app-nav__item.is-active {
  border-color: var(--border-subtle);
}

@media (max-width: 859px) {
  .app-nav {
    border-right: none;
    border-top: 1px solid var(--border-subtle);
    bottom: 0;
    flex-direction: row;
    justify-content: space-around;
    left: 0;
    padding: var(--space-xs) var(--space-sm);
    position: fixed;
    right: 0;
    width: 100%;
    z-index: calc(var(--z-overlay) - 1);
  }

  .app-nav__item {
    flex: 1;
    max-width: 3.5rem;
  }

  .app-nav__item::after {
    display: none;
  }
}