/* ============================================
   NAVIGATION
   ============================================ */

.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: var(--z-nav);
  height: var(--nav-height);
  display: flex;
  align-items: center;
}

.nav::before {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(10, 10, 10, 0);
  backdrop-filter: blur(0px);
  border-bottom: 1px solid transparent;
  transition: background var(--dur-normal) var(--ease-out),
              backdrop-filter var(--dur-normal) var(--ease-out),
              border-color var(--dur-normal) var(--ease-out);
  z-index: -1;
}
.nav.scrolled::before {
  background: rgba(10, 10, 10, 0.88);
  backdrop-filter: blur(20px) saturate(180%);
  border-color: var(--color-border);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
  gap: var(--space-8);
}

/* ── Logo ── */
.nav__logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-text-primary);
  transition: opacity var(--dur-fast);
  flex-shrink: 0;
}
.nav__logo:hover { opacity: 0.75; }

/* Geometric SR logo mark (SVG injected) */
.nav__logo-mark {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.nav__logo-mark svg {
  width: 100%;
  height: 100%;
}

.nav__logo-name {
  font-family: var(--font-display);
  font-weight: var(--weight-semibold);
  font-size: var(--text-sm);
  letter-spacing: 0.01em;
  color: var(--color-text-primary);
}

/* ── Desktop Links ── */
.nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-8);
  margin: 0 auto;
}

.nav__link {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: var(--weight-regular);
  color: var(--color-text-secondary);
  letter-spacing: 0.01em;
  position: relative;
  padding: var(--space-2) 0;
  min-height: 44px;  /* tap target */
  display: inline-flex;
  align-items: center;
  transition: color var(--dur-fast);
}
.nav__link::after {
  content: '';
  position: absolute;
  bottom: 4px; left: 0;
  width: 0; height: 1px;
  background: var(--color-text-primary);
  transition: width var(--dur-normal) var(--ease-out);
}
.nav__link:hover         { color: var(--color-text-primary); }
.nav__link:hover::after  { width: 100%; }
.nav__link.active        { color: var(--color-text-primary); font-weight: var(--weight-medium); }
.nav__link.active::after { width: 100%; }

/* ── Nav CTA Button ── */
.btn-nav {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 10px 22px;
  min-height: 44px;
  border-radius: var(--radius-full);
  border: 1.5px solid rgba(255, 255, 255, 0.25);
  background: transparent;
  color: var(--color-text-primary);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  letter-spacing: 0.01em;
  white-space: nowrap;
  flex-shrink: 0;
  transition: background var(--dur-normal) var(--ease-out),
              color var(--dur-normal) var(--ease-out),
              border-color var(--dur-normal),
              transform var(--dur-normal) var(--ease-spring);
}
.btn-nav:hover {
  background: var(--color-text-primary);
  color: var(--color-bg);
  border-color: var(--color-text-primary);
  transform: scale(1.02);
}
.btn-nav:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

/* ── Mobile Hamburger Button ── */
.nav__menu-btn {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-3);
  flex-shrink: 0;
  transition: border-color var(--dur-fast), background var(--dur-fast);
}
.nav__menu-btn:hover {
  border-color: var(--color-border-hover);
  background: var(--color-surface);
}
.nav__menu-btn:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

.nav__menu-btn span {
  display: block;
  width: 18px;
  height: 1.5px;
  background: var(--color-text-primary);
  border-radius: 2px;
  transition: transform var(--dur-normal) var(--ease-out),
              opacity var(--dur-normal),
              width var(--dur-normal) var(--ease-out);
}
/* Open state — X */
.nav__menu-btn.open span:nth-child(1) { transform: rotate(45deg) translate(4.5px, 4.5px); }
.nav__menu-btn.open span:nth-child(2) { opacity: 0; width: 0; }
.nav__menu-btn.open span:nth-child(3) { transform: rotate(-45deg) translate(4.5px, -4.5px); }

/* ── Mobile Drawer ── */
.nav__drawer {
  position: fixed;
  top: var(--nav-height);
  left: 0; right: 0;
  background: rgba(10, 10, 10, 0.97);
  backdrop-filter: blur(24px) saturate(180%);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-6) var(--gutter) var(--space-10);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  z-index: var(--z-drawer);
  /* Hidden state */
  transform: translateY(-8px);
  opacity: 0;
  pointer-events: none;
  visibility: hidden;
  transition: transform var(--dur-normal) var(--ease-out),
              opacity var(--dur-normal) var(--ease-out),
              visibility 0s linear var(--dur-normal);
}
.nav__drawer.open {
  transform: translateY(0);
  opacity: 1;
  pointer-events: all;
  visibility: visible;
  transition: transform var(--dur-normal) var(--ease-out),
              opacity var(--dur-normal) var(--ease-out),
              visibility 0s linear 0s;
}

/* Drawer links */
.nav__drawer .nav__link {
  font-size: var(--text-md);
  padding: var(--space-4) 0;
  min-height: 44px;
  border-bottom: 1px solid var(--color-border);
  width: 100%;
}
.nav__drawer .nav__link:last-of-type { border-bottom: none; }

/* Drawer CTA */
.nav__drawer .btn-nav {
  margin-top: var(--space-5);
  align-self: flex-start;
  padding: 12px 28px;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .nav__links  { display: none; }
  .nav__menu-btn { display: flex; }
  /* Hide desktop CTA on mobile — it's in the drawer */
  .nav__inner > .btn-nav { display: none; }
}