/* ATLAS · components/nav.css
 * Provenance: AuditHunt v3 · Phase 1.4 · amended Phase 10 2026-04-29
 * Spec: §XX.6 — 72px fixed, blur, 6 act links + ghost CTA
 * Phase 10: scroll-progress hairline, mobile hamburger + drawer, stronger active state.
 */

/* ── Nav shell ─────────────────────────────────────────────── */
.nav {
  position: fixed; top: 0; left: 0; right: 0; height: 72px;
  display: grid; grid-template-columns: auto 1fr auto;
  align-items: center; gap: 32px; padding: 0 32px;
  background: color-mix(in oklab, var(--ink) 72%, transparent);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  z-index: 10;
  transition: border-color 200ms var(--ease-out-expo);
  border-bottom: 1px solid transparent;
}
.nav.scrolled { border-bottom-color: var(--line); }

/* ── Scroll-progress hairline ──────────────────────────────── */
.nav::after {
  content: "";
  position: absolute; bottom: 0; left: 0;
  width: calc(var(--scroll-progress, 0) * 100%);
  height: 1px;
  background: var(--accent-depth, var(--shield-hi));
  opacity: 0.55;
  pointer-events: none;
  transition: width 80ms var(--ease-linear);
}
@media (prefers-reduced-motion: reduce) {
  .nav::after { transition: none; }
}

/* ── Lockup ────────────────────────────────────────────────── */
.nav-lockup img { display: block; height: 28px; }

/* ── Desktop links ─────────────────────────────────────────── */
.nav-links { display: flex; gap: 28px; justify-self: center; }
.nav-link {
  font-family: var(--f-mono); font-size: 11px; letter-spacing: 0.22em;
  text-transform: uppercase; color: var(--ash); text-decoration: none;
  position: relative; padding: 4px 0;
  transition: color 200ms var(--ease-out-expo);
}
.nav-link::after {
  content: ""; position: absolute; left: 0; right: 100%; bottom: 0; height: 2px;
  background: var(--gold);
  transition: right 200ms var(--ease-out-expo);
}
.nav-link:hover { color: var(--bone); }
.nav-link.active { color: var(--bone); }
.nav-link.active::after { right: 0; }

/* ── Mobile hamburger toggle ───────────────────────────────── */
.nav-toggle {
  display: none;
  background: none; border: none; cursor: pointer;
  padding: 8px; margin: -8px;
  color: var(--ash);
  flex-direction: column; gap: 5px; align-items: center;
  transition: color 200ms var(--ease-out-expo);
}
.nav-toggle:hover { color: var(--bone); }
.nav-toggle span {
  display: block; width: 22px; height: 1px;
  background: currentColor;
  transition: transform 240ms var(--ease-out-expo), opacity 200ms var(--ease-out-expo);
}
/* Open state */
.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0; transform: scaleX(0);
}
.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

/* ── Mobile drawer ─────────────────────────────────────────── */
.nav-drawer {
  position: fixed; top: 72px; left: 0; right: 0;
  background: color-mix(in oklab, var(--ink) 92%, transparent);
  backdrop-filter: blur(24px); -webkit-backdrop-filter: blur(24px);
  border-bottom: 1px solid var(--line);
  padding: 24px 32px 32px;
  display: flex; flex-direction: column; gap: 4px;
  z-index: 9;
  /* hidden by default */
  opacity: 0; pointer-events: none;
  transform: translateY(-8px);
  transition: opacity 220ms var(--ease-out-expo), transform 220ms var(--ease-out-expo);
}
.nav-drawer.open {
  opacity: 1; pointer-events: auto;
  transform: translateY(0);
}
.nav-drawer a {
  font-family: var(--f-mono); font-size: 13px; letter-spacing: 0.18em;
  text-transform: uppercase; color: var(--ash); text-decoration: none;
  padding: 14px 0; border-bottom: 1px solid var(--line);
  display: flex; justify-content: space-between; align-items: center;
  transition: color 160ms var(--ease-out-expo);
}
.nav-drawer a:last-of-type { border-bottom: none; }
.nav-drawer a:hover, .nav-drawer a.active { color: var(--bone); }
.nav-drawer a.active::after { content: "◦"; color: var(--gold); font-size: 14px; }

@media (prefers-reduced-motion: reduce) {
  .nav-toggle span { transition: none; }
  .nav-drawer { transition: none; }
}

/* ── Responsive ────────────────────────────────────────────── */
@media (max-width: 720px) {
  .nav-links { display: none; }
  .nav-toggle { display: flex; }
  .nav > .btn { display: none; } /* hide CTA on mobile — drawer has it */
}