/* ==========================================================================
   Navigation — progress bar, sticky header, mobile menu, side rail dots
   ========================================================================== */

.progress-bar-wrap {
  position: fixed;
  inset: 0 0 auto 0;
  height: 3px;
  z-index: var(--z-progress);
  background: transparent;
}

.progress-bar {
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--color-blue), var(--accent));
  transition: width 0.15s linear;
}

/* ---- Header ---- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: var(--z-nav);
  padding: var(--space-md) 0;
  transition: padding var(--dur-med) var(--ease-out),
              background var(--dur-med) var(--ease-out),
              border-color var(--dur-med) var(--ease-out);
  border-bottom: 1px solid transparent;
}

.site-header.is-scrolled {
  padding: var(--space-xs) 0;
  background: rgba(6, 15, 34, 0.82);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom-color: var(--border-subtle);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
}

.brand {
  display: flex;
  align-items: center;
}

.brand img {
  height: 52px;
  width: auto;
}

.primary-nav {
  display: flex;
  align-items: center;
  gap: var(--space-2xs);
}

.nav-link {
  position: relative;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.55);
  padding: 0.5rem 0.9rem;
  border-radius: var(--radius-sm);
  transition: color var(--dur-fast) var(--ease-out), background var(--dur-fast) var(--ease-out);
}

.nav-link:hover,
.nav-link.is-active {
  color: var(--accent);
  background: var(--color-teal-dim);
}

.nav-link--cta {
  margin-left: var(--space-2xs);
  color: var(--accent);
  border: 1px solid var(--border-accent);
}

.nav-link--cta:hover {
  background: var(--color-teal-dim);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  align-items: center;
}

.nav-toggle span {
  display: block;
  width: 18px;
  height: 1.5px;
  background: var(--text-primary);
  transition: transform var(--dur-fast) var(--ease-out), opacity var(--dur-fast) var(--ease-out);
}

.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(6.5px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-6.5px) rotate(-45deg);
}

/* ---- Side rail dots (desktop only, decorative wayfinding) ---- */
.side-rail {
  position: fixed;
  right: var(--space-lg);
  top: 50%;
  transform: translateY(-50%);
  z-index: var(--z-dots);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.side-rail__dot {
  position: relative;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.22);
  transition: background var(--dur-fast) var(--ease-out), transform var(--dur-fast) var(--ease-out);
}

.side-rail__dot:hover,
.side-rail__dot.is-active {
  background: var(--accent);
  transform: scale(1.4);
  box-shadow: 0 0 10px rgba(0, 245, 160, 0.6);
}

.side-rail__dot::after {
  content: attr(data-label);
  position: absolute;
  right: 14px;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 0.58rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  white-space: nowrap;
  color: var(--text-muted);
  text-shadow: 0 1px 4px rgba(2, 8, 22, 0.9), 0 0 10px rgba(2, 8, 22, 0.75);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--dur-fast) var(--ease-out);
}

.side-rail__dot:hover::after {
  opacity: 1;
}

/* Active section's label stays visible without hovering — the dot alone
   doesn't make it obvious the rail is navigable, so the current section
   name persists beside it until scroll moves to the next section. Plain
   text (no chip/background) so it reads as a quiet caption, not a button
   competing with page content. */
.side-rail__dot.is-active::after {
  opacity: 1;
  pointer-events: auto;
  color: var(--accent);
}

@media (max-width: 900px) {
  .side-rail {
    display: none;
  }

  .primary-nav {
    position: fixed;
    inset: 0 0 0 auto;
    width: min(78vw, 340px);
    height: 100vh;
    background: var(--color-navy-950);
    border-left: 1px solid var(--border-subtle);
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    gap: var(--space-md);
    padding: var(--space-xl);
    transform: translateX(100%);
    transition: transform var(--dur-med) var(--ease-out);
  }

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

  .nav-link {
    font-size: 0.95rem;
  }

  .nav-toggle {
    display: flex;
  }
}