/* ═══════════════════════════════════════════════
   Shell — Navigation, Hamburger, Dark Mode Toggle
   ═══════════════════════════════════════════════ */

/* ── Nav ── */
.shell-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  z-index: 200;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  transition: background 0.25s ease, border-color 0.25s ease,
              box-shadow 0.25s ease;
}

.shell-nav.scrolled {
  box-shadow: 0 1px 16px rgba(0,0,0,0.08);
}

[data-theme="dark"] .shell-nav.scrolled {
  box-shadow: 0 1px 16px rgba(0,0,0,0.4);
}

.nav-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

/* Brand */
.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  flex-shrink: 0;
}

.nav-brand-name {
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.nav-brand-dot {
  color: var(--accent);
}

/* Desktop links */
.nav-links {
  display: none;
  align-items: center;
  gap: var(--space-1);
  list-style: none;
}

.nav-links a {
  display: block;
  padding: 6px 12px;
  font-family: var(--font-display);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: color 0.15s, background 0.15s;
}

.nav-links a:hover {
  color: var(--text-primary);
  background: var(--bg-muted);
}

/* Nav right cluster */
.nav-right {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* Dark mode toggle */
.dark-toggle {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  background: none;
  border: 1px solid var(--border);
  cursor: pointer;
  transition: color 0.15s, background 0.15s, border-color 0.15s;
  flex-shrink: 0;
}

.dark-toggle:hover {
  color: var(--text-primary);
  background: var(--bg-muted);
}

.dark-toggle .icon-sun  { display: none; }
.dark-toggle .icon-moon { display: block; }

[data-theme="dark"] .dark-toggle .icon-sun  { display: block; }
[data-theme="dark"] .dark-toggle .icon-moon { display: none; }

/* Nav CTA button */
.nav-cta-btn {
  display: none;
  padding: 8px 18px;
  background: var(--accent);
  color: #fff;
  font-family: var(--font-display);
  font-size: 0.8125rem;
  font-weight: 700;
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: background 0.15s, transform 0.15s;
  white-space: nowrap;
}

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

/* Hamburger */
.hamburger {
  width: 36px;
  height: 36px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: none;
  cursor: pointer;
  padding: 0;
  transition: background 0.15s;
  flex-shrink: 0;
}

.hamburger:hover { background: var(--bg-muted); }

.hamburger-line {
  display: block;
  width: 16px;
  height: 1.5px;
  background: var(--text-secondary);
  border-radius: 2px;
  transition: transform 0.25s ease, opacity 0.25s ease, width 0.25s ease;
  transform-origin: center;
}

.hamburger[aria-expanded="true"] .hamburger-line:nth-child(1) {
  transform: translateY(6.5px) rotate(45deg);
}
.hamburger[aria-expanded="true"] .hamburger-line:nth-child(2) {
  opacity: 0;
  width: 0;
}
.hamburger[aria-expanded="true"] .hamburger-line:nth-child(3) {
  transform: translateY(-6.5px) rotate(-45deg);
}

/* Mobile drawer */
.mobile-drawer {
  position: fixed;
  top: var(--nav-h);
  left: 0; right: 0;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  padding: var(--space-4) var(--space-6) var(--space-6);
  z-index: 190;
  transform: translateY(-100%);
  opacity: 0;
  pointer-events: none;
  transition: transform 0.28s cubic-bezier(0.4, 0, 0.2, 1),
              opacity 0.28s ease;
}

.mobile-drawer.open {
  transform: translateY(0);
  opacity: 1;
  pointer-events: auto;
}

.mobile-drawer nav {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.mobile-drawer nav a {
  display: block;
  padding: 10px var(--space-4);
  font-family: var(--font-display);
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius-md);
  transition: color 0.15s, background 0.15s;
}

.mobile-drawer nav a:hover {
  color: var(--accent);
  background: var(--accent-xlight);
}

.mobile-drawer-cta {
  margin-top: var(--space-4);
  padding-top: var(--space-4);
  border-top: 1px solid var(--border);
}

.mobile-drawer-cta a {
  display: block;
  text-align: center;
  padding: 11px;
  background: var(--accent);
  color: #fff !important;
  font-family: var(--font-display);
  font-size: 0.9375rem;
  font-weight: 700;
  border-radius: var(--radius-md);
  transition: background 0.15s;
}

.mobile-drawer-cta a:hover {
  background: var(--accent-dark) !important;
}

/* Overlay */
.mobile-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.35);
  z-index: 180;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.28s ease;
}

.mobile-overlay.open {
  opacity: 1;
  pointer-events: auto;
}

/* ── Breakpoints ── */
@media (min-width: 768px) {
  .nav-links    { display: flex; }
  .nav-cta-btn  { display: inline-flex; }
  .hamburger    { display: none; }
}