/* ===================================================================
   ITD Next Dimension — Navigation (glass pill)
   =================================================================== */

.nav {
  position: fixed;
  top: 16px;
  left: 16px;
  right: 16px;
  z-index: 100;
  height: 64px;
  border-radius: var(--radius-nav);
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--border);
  backdrop-filter: blur(20px) saturate(160%);
  -webkit-backdrop-filter: blur(20px) saturate(160%);
  transition: background var(--t-base), border-color var(--t-base), box-shadow var(--t-base);
}

[data-theme="dark"] .nav {
  background: rgba(20, 20, 26, 0.72);
}

.nav.scrolled {
  box-shadow: 0 8px 32px -16px var(--halo);
}

.nav-inner {
  display: flex;
  align-items: center;
  height: 100%;
  max-width: calc(var(--max-width) + 56px);
  margin: 0 auto;
  padding: 0 24px;
  gap: 32px;
}

/* ----- Logo (PNG mark + ITD + serif Next Dimension) ----- */

.nav-logo {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
}

.nav-logo .logo-mark {
  width: 38px;
  height: 28px;
  background: var(--nd-mark) center/contain no-repeat;
  flex-shrink: 0;
}

.nav-logo .logo-wordmark {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  line-height: 1;
}

.nav-logo .logo-itd {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 16px;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.nav-logo .logo-nd {
  font-family: var(--font-serif);
  font-style: italic;
  font-size: 18px;
  color: var(--ink-2);
  letter-spacing: -0.01em;
}

/* ----- Links ----- */

.nav-links {
  flex: 1;
  display: flex;
  justify-content: center;
  gap: 28px;
}

.nav-links a {
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 500;
  color: var(--ink-2);
  letter-spacing: -0.005em;
  transition: color var(--t-base);
  position: relative;
}

.nav-links a:hover { color: var(--ink); }

.nav-links a.active {
  color: var(--ink);
}

.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--ink);
}

/* ----- Dropdown ----- */

.nav-dropdown {
  position: relative;
  display: inline-flex;
  align-items: center;
}

.nav-dropdown-trigger {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 0;
  background: transparent;
  border: none;
  -webkit-appearance: none;
          appearance: none;
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 500;
  color: var(--ink-2);
  letter-spacing: -0.005em;
  cursor: pointer;
  white-space: nowrap;
  transition: color var(--t-base);
  line-height: 1;
}

.nav-dropdown-trigger:hover,
.nav-dropdown-trigger[aria-expanded="true"] {
  color: var(--ink);
}

.nav-dropdown-trigger .chevron {
  width: 10px;
  height: 10px;
  display: inline-block;
  flex-shrink: 0;
  color: currentColor;
  transition: transform var(--t-base);
}

.nav-dropdown-trigger[aria-expanded="true"] .chevron {
  transform: rotate(180deg);
}

.nav-dropdown-menu {
  position: absolute;
  top: calc(100% + 20px);
  left: 50%;
  transform: translateX(-50%) translateY(-6px);
  min-width: 280px;
  padding: 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  box-shadow:
    0 24px 48px -16px rgba(0, 0, 0, 0.16),
    0 4px 12px -4px rgba(0, 0, 0, 0.06);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition:
    opacity var(--t-base),
    transform var(--t-base),
    visibility 0s linear var(--t-base);
  z-index: 110;
}

.nav-dropdown-trigger[aria-expanded="true"] + .nav-dropdown-menu {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0);
  transition:
    opacity var(--t-base),
    transform var(--t-base),
    visibility 0s linear 0s;
}

.nav-dropdown-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 14px;
  border-radius: 10px;
  color: var(--ink);
  text-decoration: none;
  transition: background var(--t-base);
}

.nav-dropdown-item:hover {
  background: var(--bg-deep);
}

.nav-dropdown-item .dropdown-item-title {
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 500;
  color: var(--ink);
  letter-spacing: -0.005em;
}

.nav-dropdown-item .dropdown-item-arrow {
  font-size: 14px;
  color: var(--ink-3);
  transition: color var(--t-base), transform var(--t-base);
}

.nav-dropdown-item:hover .dropdown-item-arrow {
  color: var(--ink);
  transform: translate(2px, -2px);
}

/* ----- CTA ----- */

.nav-cta {
  display: flex;
  align-items: center;
  gap: 14px;
}

.nav-cta .nav-signin {
  font-size: 14px;
  color: var(--ink-2);
  font-weight: 500;
  transition: color var(--t-base);
}

.nav-cta .nav-signin:hover { color: var(--ink); }

.nav-cta .btn {
  padding: 9px 18px;
  font-size: 13px;
}

/* ----- Hamburger ----- */

.nav-hamburger {
  display: none;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 10px;
  width: 40px;
  height: 40px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  cursor: pointer;
  transition: border-color var(--t-base);
}

.nav-hamburger:hover { border-color: var(--ink); }

.nav-hamburger span {
  width: 16px;
  height: 1.5px;
  background: var(--ink);
  transition: transform var(--t-base), opacity var(--t-base);
}

.nav-hamburger[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(5.5px) rotate(45deg);
}

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

.nav-hamburger[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-5.5px) rotate(-45deg);
}

/* ----- Theme switcher ----- */

.theme-switch {
  display: inline-flex;
  align-items: center;
  padding: 4px;
  border-radius: var(--radius-pill);
  background: var(--bg-deep);
  border: 1px solid var(--border);
  gap: 2px;
}

.theme-switch button {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: transparent;
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--ink-3);
  transition: color var(--t-base), background var(--t-base);
}

.theme-switch button:hover { color: var(--ink); }
.theme-switch button.active { background: var(--surface); color: var(--ink); }

.theme-switch svg { width: 14px; height: 14px; }

/* ----- Mobile overlay ----- */

.nav-mobile-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--bg);
  z-index: 99;
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 24px;
  padding: 80px 24px 40px;
}

.nav-mobile-overlay.active {
  display: flex;
}

.nav-mobile-overlay a:not(.btn) {
  font-family: var(--font-sans);
  font-size: 24px;
  font-weight: 500;
  color: var(--ink);
  letter-spacing: -0.02em;
}

.nav-mobile-overlay a:not(.btn).active {
  font-family: var(--font-serif);
  font-style: italic;
  font-weight: 400;
}

.nav-mobile-overlay .btn {
  margin-top: 12px;
  font-size: 15px;
  padding: 14px 26px;
}