/* Sidebar navigation */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--nav-width);
  height: 100vh;
  background: var(--bg-nav);
  padding: var(--space-lg) var(--space-lg) var(--space-lg) var(--space-lg);
  overflow-y: auto;
  z-index: 100;
  display: flex;
  flex-direction: column;
  border-right: 1px solid var(--rule);
}

.nav__list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.nav__item {
  margin-bottom: 2px;
  transition: margin-bottom var(--duration) var(--ease);
}

.nav__item:has(.nav__link[data-caption]:hover) {
  margin-bottom: 12px;
}

.nav__link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: var(--space-sm);
  padding: 3px 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent);
  text-decoration: none;
  transition: opacity var(--duration) var(--ease);
  white-space: nowrap;
}

.nav__link:hover {
  color: var(--gold);
}

.nav__link[data-caption]::after {
  content: attr(data-caption);
  position: absolute;
  left: calc(1.5em + var(--space-sm));
  top: 100%;
  font-family: var(--font-mono);
  font-size: 0.5rem;
  font-weight: 400;
  letter-spacing: 0.03em;
  color: var(--text-dim);
  white-space: nowrap;
  opacity: 0;
  transform: translateY(-2px);
  transition: opacity var(--duration) var(--ease), transform var(--duration) var(--ease);
  pointer-events: none;
}

.nav__link[data-caption]:hover::after {
  opacity: 1;
  transform: translateY(0);
}

.nav__link--active {
  opacity: 1;
  font-weight: 700;
}

.nav__link--home {
  color: var(--green);
  font-size: 0.8125rem;
  font-weight: 700;
  margin-bottom: var(--space-md);
  opacity: 1;
}

.nav__link--meta {
  color: var(--gold);
}

.nav__num {
  font-size: 0.625rem;
  color: var(--text-dim);
  min-width: 1.5em;
  font-variant-numeric: tabular-nums;
}

.nav__category {
  font-family: var(--font-mono);
  font-size: 0.5625rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--text-dim);
  margin-top: var(--space-md);
  margin-bottom: var(--space-xs);
  padding-left: calc(1.5em + var(--space-sm));
}

/* Hamburger button */
.nav__toggle {
  display: none;
  position: fixed;
  top: var(--space-md);
  left: var(--space-md);
  z-index: 200;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.nav__toggle-bar {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  margin-bottom: 6px;
  transition: transform var(--duration) var(--ease), opacity var(--duration) var(--ease);
}

.nav__toggle-bar:last-child {
  margin-bottom: 0;
}

/* Hamburger open state */
.nav__toggle--open .nav__toggle-bar:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav__toggle--open .nav__toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav__toggle--open .nav__toggle-bar:nth-child(3) {
  transform: rotate(-45deg) translate(6px, -6px);
}

/* Desktop: sidebar always visible */
@media (min-width: 1200px) {
  .nav {
    width: var(--nav-width);
  }
}

/* Tablet: narrower sidebar */
@media (min-width: 769px) and (max-width: 1199px) {
  .nav {
    width: var(--nav-width-tablet);
    padding: var(--space-md);
  }

  .nav__link {
    font-size: 0.6875rem;
  }
}

/* Mobile: hamburger overlay */
@media (max-width: 768px) {
  .nav__toggle {
    display: block;
  }

  .nav {
    transform: translateX(-100%);
    transition: transform var(--duration) var(--ease);
    width: 280px;
    padding: var(--space-3xl) var(--space-lg) var(--space-lg);
  }

  .nav--open {
    transform: translateX(0);
  }

  /* Backdrop */
  .nav--open::after {
    content: '';
    position: fixed;
    top: 0;
    left: 280px;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.15);
  }

  .nav__link[data-caption]::after {
    display: none;
  }
}