/* ============================================================
   Floating pill nav — hide on scroll-down, show on scroll-up
   ============================================================ */

.nav {
  position: fixed;
  top: 18px;
  left: 50%;
  translate: -50% 0;
  z-index: var(--z-nav);
  display: flex;
  gap: 4px;
  padding: 6px;
  border-radius: var(--r-pill);
  background: rgba(18, 18, 18, 0.6);
  border: 1px solid var(--border);
  backdrop-filter: blur(14px) saturate(1.3);
  -webkit-backdrop-filter: blur(14px) saturate(1.3);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
  transition: translate 0.45s var(--ease-out), opacity 0.35s ease;
  will-change: translate;
}

/* hidden (scrolling down) */
.nav.is-hidden {
  translate: -50% -160%;
  opacity: 0;
  pointer-events: none;
}

.nav__link {
  position: relative;
  padding: 8px 18px;
  border-radius: var(--r-pill);
  font-size: var(--step--1);
  font-weight: 600;
  color: var(--fg-dim);
  white-space: nowrap;
  transition: color 0.25s ease, background 0.25s ease;
}
.nav__link:hover { color: var(--fg); }

.nav__link.is-active {
  color: #0a0a0a;
  background: var(--accent);
}

/* mobile: collapse handled in a later phase */
@media (max-width: 640px) {
  .nav { gap: 0; padding: 5px; }
  .nav__link { padding: 8px 12px; }
}