/* ============================================================
   HEADER — fixed, backdrop-blur, mobile hamburger
   ============================================================ */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: var(--z-header);
  display: flex;
  justify-content: center;
  padding: var(--space-5) var(--gutter);
  animation: fadeInUp 900ms var(--ease-out) both;
  transition:
    padding var(--dur-base) var(--ease-out),
    background var(--dur-base) var(--ease-out);
}

/* Scroll state — shrink + solid bg */
.site-header.is-scrolled {
  padding-top: var(--space-3);
  padding-bottom: var(--space-3);
  background: rgba(10, 10, 10, 0.85);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--line-1);
}

.nav {
  width: 100%;
  max-width: var(--container);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-3) var(--space-4);
  background: rgba(10, 10, 10, 0.65);
  border: 1px solid var(--line-2);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}
.site-header.is-scrolled .nav {
  background: transparent;
  border-color: transparent;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
}

/* Brand */
.nav__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
}
.nav__logo {
  width: 28px;
  height: 30px;
  display: block;
}
.nav__wordmark {
  display: none;
}

/* Desktop links — hidden on mobile (mobile-first) */
.nav__links {
  display: none;
  gap: var(--space-6);
}
.nav__links a {
  font-size: var(--fs-xs);
  font-family: var(--font-mono);
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  color: var(--text-3);
  transition: color var(--dur-fast) var(--ease-out);
}
.nav__links a:hover { color: var(--text-1); }

/* Mobile hamburger toggle — visible on mobile */
.nav__toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: transparent;
  border: 1px solid var(--line-2);
  cursor: pointer;
}
.nav__toggle span {
  display: block;
  width: 18px;
  height: 1.5px;
  background: var(--text-1);
  position: relative;
  transition: background var(--dur-base) var(--ease-out);
}
.nav__toggle span::before,
.nav__toggle span::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 1.5px;
  background: var(--text-1);
  transition: transform var(--dur-base) var(--ease-out);
}
.nav__toggle span::before { top: -6px; }
.nav__toggle span::after  { top: 6px; }
.nav__toggle.is-open span { background: transparent; }
.nav__toggle.is-open span::before { transform: translateY(6px) rotate(45deg); }
.nav__toggle.is-open span::after  { transform: translateY(-6px) rotate(-45deg); }

/* Mobile fullscreen overlay menu */
.nav__mobile {
  position: fixed;
  inset: 0;
  z-index: calc(var(--z-header) - 1);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: var(--space-6);
  padding: var(--space-16) var(--gutter);
  background: rgba(10, 10, 10, 0.97);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  opacity: 0;
  visibility: hidden;
  transition:
    opacity var(--dur-base) var(--ease-out),
    visibility var(--dur-base);
}
.nav__mobile.is-open {
  opacity: 1;
  visibility: visible;
}
.nav__mobile a {
  font-family: var(--font-display);
  font-size: var(--fs-2xl);
  font-weight: var(--fw-medium);
  letter-spacing: var(--tracking-tight);
  color: var(--text-2);
  padding: var(--space-2) 0;
  transition: color var(--dur-fast) var(--ease-out);
}
.nav__mobile a:hover { color: var(--text-1); }

/* ---------------------------------------------------------------
   MOBILE — hamburger visible, links hidden, header compacto
   --------------------------------------------------------------- */
@media (max-width: 767px) {
  .nav__links { display: none !important; }
  .nav__toggle { display: inline-flex !important; }

  .site-header {
    padding-top: var(--space-3);
    padding-bottom: var(--space-3);
  }

  .nav {
    padding-top: var(--space-2);
    padding-bottom: var(--space-2);
  }
}

/* ---------------------------------------------------------------
   DESKTOP OVERRIDES — MUST be last to win cascade
   --------------------------------------------------------------- */
@media (min-width: 768px) {
  .nav__links { display: inline-flex !important; }
  .nav__toggle { display: none !important; }
  .nav__mobile { display: none !important; }
}