/* ============================================================
   PARCO Lab — nav.css
   Frosted glass nav · Language switcher · Theme toggle
   ============================================================ */

/* ── Fixed top nav ── */
.nav {
  position: fixed; top: 0; left: 0; right: 0;
  height: var(--space-nav); z-index: 1000;
  background: var(--bg-nav);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--divider);
  transition: background 0.3s var(--ease-apple), border-color 0.3s var(--ease-apple);
}

.nav-inner {
  max-width: var(--max-w-wide); margin: 0 auto;
  height: 100%; display: flex; align-items: center;
  padding: 0 clamp(16px,3vw,44px); gap: 0;
}

/* ── Logo ── */
.nav-logo {
  display: flex; align-items: center;
  text-decoration: none; flex-shrink: 0; margin-right: 24px;
  height: 36px;
}
/* Constrain by height, let width scale naturally with SVG aspect ratio */
.nav-logo-img-light,
.nav-logo-img-dark {
  height: 36px;
  width: auto;
}
/* Light logo shown in light theme, dark logo in dark theme */
.nav-logo-img-light { display: block; }
.nav-logo-img-dark  { display: none;  }
[data-theme="dark"] .nav-logo-img-light { display: none; }
[data-theme="dark"] .nav-logo-img-dark  { display: block; }

/* ── Desktop links ── */
.nav-links {
  flex: 1; display: flex; align-items: center;
  justify-content: center; gap: 0; list-style: none;
}
.nav-links a {
  font-size: var(--text-nav); font-weight: 400;
  color: var(--text-primary); text-decoration: none;
  padding: 0 11px; height: var(--space-nav);
  display: flex; align-items: center;
  opacity: 0.8; white-space: nowrap;
  transition: opacity var(--dur-fast) var(--ease-apple);
}
.nav-links a:hover  { opacity: 1; }
.nav-links a.active { opacity: 1; font-weight: 600; }

/* ── Nav right controls ── */
.nav-right {
  display: flex; align-items: center; gap: 12px; flex-shrink: 0;
}

/* ── Language switcher ── */
.lang-switcher {
  display: flex; align-items: center;
  background: var(--bg-tertiary);
  border-radius: 980px;
  padding: 3px;
  gap: 2px;
}
.lang-btn {
  font-family: var(--font-system);
  font-size: 11px; font-weight: 600;
  letter-spacing: 0.03em;
  padding: 3px 9px; border-radius: 980px;
  border: none; cursor: pointer;
  background: transparent; color: var(--text-secondary);
  transition: background var(--dur-fast) var(--ease-apple),
              color var(--dur-fast) var(--ease-apple),
              box-shadow var(--dur-fast) var(--ease-apple);
  -webkit-font-smoothing: antialiased;
}
.lang-btn.active {
  background: var(--bg-primary);
  color: var(--text-primary);
  box-shadow: var(--shadow-xs);
}
.lang-btn:hover:not(.active) { color: var(--text-primary); }

/* ── Theme toggle ── */
.theme-toggle {
  width: 32px; height: 20px;
  background: var(--bg-tertiary); border-radius: 10px;
  border: none; cursor: pointer; position: relative; padding: 0;
  transition: background var(--dur-fast) var(--ease-apple);
  flex-shrink: 0;
}
.theme-toggle::after {
  content: '';
  position: absolute; top: 2px; left: 2px;
  width: 16px; height: 16px; border-radius: 50%;
  background: var(--bg-primary); box-shadow: var(--shadow-xs);
  transition: left var(--dur-med) var(--ease-spring),
              background var(--dur-fast) var(--ease-apple);
}
[data-theme="dark"] .theme-toggle           { background: #636366; }
[data-theme="dark"] .theme-toggle::after    { left: 14px; background: #FFF; }

/* ── CTA ── */
.nav-cta {
  font-size: var(--text-caption); color: var(--accent);
  text-decoration: none; white-space: nowrap;
  transition: color var(--dur-fast) var(--ease-apple);
}
.nav-cta:hover { color: var(--accent-hover); }

/* ── Hamburger ── */
.hamburger {
  display: none; flex-direction: column; gap: 5px;
  cursor: pointer; background: none; border: none; padding: 6px;
}
.hamburger span {
  display: block; width: 18px; height: 1.5px;
  background: var(--text-primary); border-radius: 2px;
  transition: transform 0.25s var(--ease-apple), opacity 0.2s var(--ease-apple);
}
.hamburger.open span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

/* ── Mobile menu ── */
.mobile-menu {
  display: none; position: fixed;
  top: var(--space-nav); left: 0; right: 0; bottom: 0;
  background: var(--bg-nav);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  z-index: 999; flex-direction: column;
  padding: 20px clamp(20px,5vw,44px);
  border-top: 1px solid var(--divider); overflow-y: auto;
}
.mobile-menu.open { display: flex; }

/* Mobile lang switcher (larger) */
.mobile-lang {
  display: flex; gap: 8px; margin-bottom: 20px;
}
.mobile-lang .lang-btn {
  font-size: 13px; padding: 6px 18px;
  border-radius: 980px;
  border: 1px solid var(--divider);
  background: var(--bg-card); color: var(--text-secondary);
}
.mobile-lang .lang-btn.active {
  background: var(--accent); color: #FFF; border-color: var(--accent);
  box-shadow: none;
}

.mobile-menu-link {
  font-size: clamp(22px,4vw,28px); font-weight: 700; letter-spacing: -0.01em;
  color: var(--text-primary); text-decoration: none;
  padding: 14px 0; border-bottom: 1px solid var(--divider);
  display: flex; align-items: center; justify-content: space-between;
  transition: color var(--dur-fast) var(--ease-apple);
}
.mobile-menu-link::after { content: '›'; font-size: 0.8em; color: var(--text-tertiary); }
.mobile-menu-link:hover, .mobile-menu-link.active { color: var(--accent); }

.mobile-menu-footer {
  margin-top: auto; padding-top: 24px;
  font-size: var(--text-caption); color: var(--text-tertiary);
  display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px;
}

/* ── Responsive ── */
@media (max-width: 860px) {
  .nav-links { display: none; }
  .nav-cta   { display: none; }
  .hamburger { display: flex; }
}
@media (min-width: 861px) {
  .hamburger    { display: none !important; }
  .mobile-menu  { display: none !important; }
}
@media (max-width: 600px) {
  .lang-switcher { display: none; } /* shown only in mobile menu */
}
@media (min-width: 601px) {
  .mobile-lang { display: none; }
}