/* =============================================================================
   NAVIGATION — nav.css
   ============================================================================= */

/* ── Base Navbar ───────────────────────────────────────────────────────────── */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  transition:
    background-color var(--transition-base),
    border-color     var(--transition-base),
    box-shadow       var(--transition-base),
    transform        var(--transition-base);
}

/* Glassy backdrop after scrolling */
.navbar.scrolled {
  background: hsla(220, 16%, 7%, 0.82);
  backdrop-filter: blur(24px) saturate(140%);
  -webkit-backdrop-filter: blur(24px) saturate(140%);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
}

[data-theme="light"] .navbar.scrolled {
  background: hsla(42, 30%, 97%, 0.85);
}

/* Hide on scroll-down, reveal on scroll-up */
.navbar.nav-hidden {
  transform: translateY(-100%);
}

/* ── Container ─────────────────────────────────────────────────────────────── */
.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-6);
}

@media (min-width: 1024px) {
  .nav-container { padding-inline: var(--space-12); }
}

/* ── Logo ──────────────────────────────────────────────────────────────────── */
.nav-logo {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-text-1);
  transition: color var(--transition-fast);
  z-index: 1001;
  position: relative;
}

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

.logo-icon {
  color: var(--color-accent);
  flex-shrink: 0;
  transition: transform var(--transition-spring);
}

.nav-logo:hover .logo-icon {
  transform: rotate(-15deg) scale(1.1);
}

.logo-text {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1;
}

/* ── Nav Links (desktop) ───────────────────────────────────────────────────── */
.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: 500;
  color: var(--color-text-2);
  border-radius: var(--radius-full);
  transition: color var(--transition-fast), background-color var(--transition-fast);
  white-space: nowrap;
}

/* Animated underline */
.nav-link::after {
  content: '';
  position: absolute;
  bottom: 5px;
  left: 50%;
  transform: translateX(-50%) scaleX(0);
  width: 14px;
  height: 2px;
  background: var(--color-accent);
  border-radius: var(--radius-full);
  transition: transform var(--transition-base);
  transform-origin: center;
}

.nav-link:hover {
  color: var(--color-text-1);
}

.nav-link:hover::after,
.nav-link.active::after,
.nav-link[aria-current="page"]::after {
  transform: translateX(-50%) scaleX(1);
}

.nav-link.active,
.nav-link[aria-current="page"] {
  color: var(--color-text-1);
  font-weight: 600;
}

/* ── Nav Actions ───────────────────────────────────────────────────────────── */
.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* ── Theme Toggle ──────────────────────────────────────────────────────────── */
.theme-toggle {
  position: relative;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text-2);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-base);
  overflow: hidden;
}

.theme-toggle:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-muted);
}

/* Icon transitions */
.icon-sun,
.icon-moon {
  position: absolute;
  transition: all var(--transition-base);
}

/* Dark theme default: show moon */
.icon-sun  { opacity: 0; transform: rotate(90deg)  scale(0.6); }
.icon-moon { opacity: 1; transform: rotate(0deg)   scale(1);   }

/* Light theme: show sun */
[data-theme="light"] .icon-sun  { opacity: 1; transform: rotate(0deg)   scale(1);   }
[data-theme="light"] .icon-moon { opacity: 0; transform: rotate(-90deg) scale(0.6); }

/* ── Hamburger (mobile only) ───────────────────────────────────────────────── */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 10px;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  transition: all var(--transition-base);
  z-index: 1001;
  position: relative;
}

.hamburger:hover {
  border-color: var(--color-accent);
  background: var(--color-accent-muted);
}

.bar {
  display: block;
  width: 100%;
  height: 1.5px;
  background: var(--color-text-2);
  border-radius: var(--radius-full);
  transition: all var(--transition-base);
  transform-origin: center;
}

/* Animated to ✕ when active */
.hamburger.active .bar:nth-child(1) { transform: rotate(45deg) translate(4.8px, 4.8px); }
.hamburger.active .bar:nth-child(2) { opacity: 0; transform: scaleX(0); }
.hamburger.active .bar:nth-child(3) { transform: rotate(-45deg) translate(4.8px, -4.8px); }

/* ── Nav Overlay (mobile backdrop) ────────────────────────────────────────── */
.nav-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: hsla(220, 16%, 7%, 0.65);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  z-index: 998;
  opacity: 0;
  transition: opacity var(--transition-base);
}

/* ── Mobile Layout ─────────────────────────────────────────────────────────── */
@media (max-width: 768px) {
  .hamburger { display: flex; }

  .nav-overlay {
    display: block;
    pointer-events: none;
  }

  .nav-overlay.visible {
    opacity: 1;
    pointer-events: all;
  }

  /* Slide-in drawer */
  .nav-links {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    width: min(320px, 85vw);
    background: var(--color-bg-surface);
    border-left: 1px solid var(--color-border);
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: calc(var(--nav-height) + var(--space-6)) var(--space-6) var(--space-8);
    z-index: 999;
    overflow-y: auto;
    transform: translateX(110%);
    transition: transform var(--transition-slow);
    box-shadow: var(--shadow-xl);
  }

  .nav-links.open {
    transform: translateX(0);
  }

  .nav-link {
    padding: var(--space-4) var(--space-2);
    font-size: var(--text-lg);
    font-family: var(--font-display);
    border-radius: 0;
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text-1);
    width: 100%;
  }

  .nav-link::after {
    display: none;
  }

  .nav-link.active,
  .nav-link[aria-current="page"] {
    color: var(--color-accent);
    font-weight: 700;
  }

  .nav-link:last-child {
    border-bottom: none;
  }
}