/* ═══════════════════════════════════════════════════
   NAV — site navigation
   前衛東方官網
   ═══════════════════════════════════════════════════ */

/* ── Base ── */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 48px;
  background: transparent;
  color: var(--card);
  transition:
    background var(--duration-normal) var(--ease-out),
    color var(--duration-normal) var(--ease-out),
    padding var(--duration-normal) var(--ease-out),
    box-shadow var(--duration-normal) var(--ease-out);
}

/* ── Scrolled state ── */
.site-nav.scrolled {
  background: rgba(247, 245, 241, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  color: var(--ink);
  padding: 14px 48px;
  box-shadow: 0 2px 20px rgba(28, 27, 24, 0.08);
}

/* ── Logo ── */
.nav-logo {
  display: flex;
  flex-direction: column;
  line-height: 1;
  text-decoration: none;
  color: inherit;
  gap: 2px;
}

.nav-logo .logo-en {
  font-family: 'Cormorant Garamond', Georgia, serif;
  font-size: 1.2rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  color: inherit;
}

.nav-logo .logo-zh {
  font-family: 'Noto Serif TC', 'Noto Sans TC', serif;
  font-size: 0.6rem;
  font-weight: 300;
  letter-spacing: 0.25em;
  color: inherit;
  opacity: 0.75;
}

/* ── Menu ── */
.nav-menu {
  display: flex;
  align-items: center;
  gap: 36px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-menu a {
  font-family: 'Noto Sans TC', sans-serif;
  font-size: 0.85rem;
  font-weight: 400;
  letter-spacing: 0.05em;
  text-decoration: none;
  color: inherit;
  position: relative;
  padding-bottom: 2px;
  transition: color var(--duration-fast) var(--ease-out);
}

/* Underline animation */
.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background: currentColor;
  transition: width var(--duration-normal) var(--ease-out);
}

.nav-menu a:hover::after,
.nav-menu a:focus-visible::after {
  width: 100%;
}

.nav-menu a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
  border-radius: 2px;
}

/* ── CTA Button ── */
.nav-cta {
  font-family: 'Noto Sans TC', sans-serif;
  font-size: 0.82rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-decoration: none;
  color: var(--card);
  background: var(--accent);
  padding: 10px 24px;
  border-radius: var(--radius-sm);
  transition:
    background var(--duration-fast) var(--ease-out),
    transform var(--duration-fast) var(--ease-out);
  white-space: nowrap;
}

.nav-cta:hover {
  background: var(--accent-light);
  transform: translateY(-1px);
}

.nav-cta:active {
  transform: translateY(0);
  background: var(--accent-dark);
}

/* ── Hamburger button (hidden on desktop) ── */
.nav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  padding: 6px;
  background: transparent;
  border: none;
  cursor: pointer;
  z-index: 110;
  color: inherit;
}

.nav-hamburger span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: currentColor;
  border-radius: 2px;
  transform-origin: center;
  transition:
    transform var(--duration-normal) var(--ease-out),
    opacity var(--duration-fast) var(--ease-out),
    width var(--duration-normal) var(--ease-out);
}

/* Open state: X transform */
.nav-hamburger[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(6.5px) rotate(45deg);
}
.nav-hamburger[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
  width: 0;
}
.nav-hamburger[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-6.5px) rotate(-45deg);
}

/* ── Mobile overlay ── */
.nav-overlay {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 90;
  background: var(--dark);
  opacity: 0;
  transition: opacity var(--duration-normal) var(--ease-out);
  pointer-events: none;
}

.nav-overlay.open {
  pointer-events: auto;
  opacity: 0.97;
}

/* ══════════════════════════════════════════
   MOBILE NAV (≤ 768px)
══════════════════════════════════════════ */
@media (max-width: 768px) {
  .site-nav {
    padding: 18px 24px;
  }

  .site-nav.scrolled {
    padding: 14px 24px;
  }

  .nav-hamburger {
    display: flex;
  }

  .nav-overlay {
    display: block;
  }

  /* Menu becomes full-screen overlay panel */
  .nav-menu {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: min(340px, 85vw);
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    background: var(--dark);
    padding: 100px 40px 60px;
    z-index: 105;
    transform: translateX(100%);
    transition: transform var(--duration-normal) var(--ease-out);
    overflow-y: auto;
    pointer-events: none;
  }

  .nav-menu.open {
    transform: translateX(0);
    pointer-events: auto;
  }

  .nav-menu li {
    width: 100%;
    border-bottom: 1px solid rgba(200, 191, 176, 0.12);
  }

  .nav-menu a {
    display: block;
    padding: 18px 0;
    font-size: 1.05rem;
    letter-spacing: 0.1em;
    color: var(--bg);
  }

  .nav-menu a::after {
    display: none;
  }

  .nav-menu a:hover {
    color: var(--accent);
  }

  /* CTA inside mobile menu */
  .nav-cta {
    display: none;
  }

  /* Add LINE CTA at bottom of mobile menu via pseudo – done in HTML */
}