/* ============================================================
   NAV — Sticky, transparent → frosted dark on scroll
   Hamburger menu on mobile (≤768px)
   ============================================================ */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-8);
  transition: background 0.3s ease, backdrop-filter 0.3s ease,
              border-bottom 0.3s ease;
}

/* Scrolled state — added by nav.js */
.nav--scrolled {
  background: var(--color-bg-nav);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-accent-dim);
}

/* Logo / site name */
.nav__logo {
  font-family: var(--font-heading);
  font-weight: var(--weight-bold);
  font-size: var(--text-sm);
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  white-space: nowrap;
  transition: color 0.2s ease;
}

.nav__logo:hover {
  color: var(--color-accent);
}

/* Menu list */
.nav__menu {
  display: flex;
  list-style: none;
  gap: var(--space-8);
  margin: 0;
  padding: 0;
}

.nav__link {
  font-family: var(--font-body);
  font-weight: var(--weight-light);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  text-decoration: none;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  transition: color 0.2s ease;
}

.nav__link:hover,
.nav__link:focus-visible {
  color: var(--color-accent);
  outline: none;
}

/* Hamburger button — hidden on desktop */
.nav__hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  z-index: 101;
}

.nav__hamburger-bar {
  display: block;
  width: 24px;
  height: 1px;
  background: var(--color-text);
  transition: transform 0.25s ease, opacity 0.25s ease;
}

/* Mobile (≤768px) */
@media (max-width: 768px) {
  .nav {
    padding: 0 var(--space-6);
  }

  .nav__hamburger {
    display: flex;
  }

  .nav__menu {
    position: fixed;
    inset: 0;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--space-12);
    background: var(--color-bg);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
  }

  .nav__menu.is-open {
    opacity: 1;
    pointer-events: all;
  }

  .nav__link {
    font-size: var(--text-lg);
    letter-spacing: 0.12em;
  }

  /* Hamburger → X when open */
  .nav__hamburger[aria-expanded="true"] .nav__hamburger-bar:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
  }

  .nav__hamburger[aria-expanded="true"] .nav__hamburger-bar:nth-child(2) {
    opacity: 0;
  }

  .nav__hamburger[aria-expanded="true"] .nav__hamburger-bar:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
  }
}