/* === Navigation === */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: var(--z-nav);
  display: flex;
  align-items: center;
  padding: 0 var(--space-8);
  transition: background var(--duration-normal) var(--ease-in-out),
              border-color var(--duration-normal) var(--ease-in-out);
  border-bottom: 1px solid transparent;
}

.nav.is-scrolled {
  background: rgba(5, 10, 21, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom-color: var(--glass-border);
}

.nav__inner {
  width: 100%;
  max-width: var(--container-wide);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Logo */
.nav__logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
  letter-spacing: var(--tracking-tight);
  color: var(--color-text-primary);
  transition: opacity var(--duration-fast) var(--ease-in-out);
}

.nav__logo:hover {
  opacity: 0.85;
}

.nav__logo img {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
}

/* Desktop links */
.nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav__link {
  position: relative;
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text-secondary);
  border-radius: var(--radius-md);
  transition: all var(--duration-fast) var(--ease-in-out);
}

.nav__link:hover {
  color: var(--color-text-primary);
  background: rgba(255, 255, 255, 0.04);
}

.nav__link.is-active {
  color: var(--color-cyan);
}

.nav__link.is-active::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 50%;
  transform: translateX(-50%);
  width: 16px;
  height: 2px;
  background: var(--color-cyan);
  border-radius: var(--radius-full);
  box-shadow: 0 0 8px rgba(77, 208, 225, 0.5);
}

/* Right side actions */
.nav__actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* Language toggle */
.lang-toggle {
  display: flex;
  align-items: center;
  padding: var(--space-1) var(--space-1);
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--glass-border);
  font-size: var(--text-xs);
  font-weight: var(--font-medium);
  overflow: hidden;
}

.lang-toggle__btn {
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
  transition: all var(--duration-fast) var(--ease-in-out);
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
}

.lang-toggle__btn.is-active {
  background: rgba(77, 208, 225, 0.15);
  color: var(--color-cyan);
}

.lang-toggle__btn:hover:not(.is-active) {
  color: var(--color-text-secondary);
}

/* GitHub icon */
.nav__github {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  transition: all var(--duration-fast) var(--ease-in-out);
}

.nav__github:hover {
  color: var(--color-text-primary);
  background: rgba(255, 255, 255, 0.06);
}

.nav__github svg {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

/* Hamburger */
.nav__hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  padding: 6px;
  border-radius: var(--radius-md);
  transition: background var(--duration-fast) var(--ease-in-out);
}

.nav__hamburger:hover {
  background: rgba(255, 255, 255, 0.06);
}

.nav__hamburger span {
  display: block;
  height: 2px;
  background: var(--color-text-secondary);
  border-radius: var(--radius-full);
  transition: all var(--duration-normal) var(--ease-out-expo);
  transform-origin: center;
}

.nav__hamburger.is-open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav__hamburger.is-open span:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}

.nav__hamburger.is-open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile menu overlay */
.nav__mobile {
  display: none;
  position: fixed;
  inset: 0;
  top: var(--nav-height);
  background: rgba(5, 10, 21, 0.97);
  backdrop-filter: blur(30px);
  -webkit-backdrop-filter: blur(30px);
  z-index: var(--z-nav-mobile);
  padding: var(--space-8);
  flex-direction: column;
  gap: var(--space-2);
  opacity: 0;
  transform: translateY(-10px);
  transition: opacity var(--duration-normal) var(--ease-out-expo),
              transform var(--duration-normal) var(--ease-out-expo);
  pointer-events: none;
}

.nav__mobile.is-open {
  display: flex;
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.nav__mobile .nav__link {
  font-size: var(--text-lg);
  padding: var(--space-4) var(--space-4);
  border-radius: var(--radius-md);
}

.nav__mobile .nav__link.is-active::after {
  display: none;
}

.nav__mobile .nav__link.is-active {
  background: rgba(77, 208, 225, 0.08);
}

/* === Responsive === */
@media (max-width: 768px) {
  .nav {
    padding: 0 var(--space-4);
  }

  .nav__links {
    display: none;
  }

  .nav__hamburger {
    display: flex;
  }

  .nav__github {
    display: none;
  }
}