/* ============================================================
   Navigation - Fixed Header + Fullscreen Overlay Menu
   ============================================================ */

/* --- Fixed Header --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 9999;
  transition: background 0.5s ease, backdrop-filter 0.5s ease, transform 0.4s cubic-bezier(0.22, 1, 0.36, 1);
}

.nav.is-hidden {
  transform: translateY(-100%);
}

.nav.is-scrolled {
  background: rgba(0, 0, 0, 0.85);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
}

.nav__bar {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 24px var(--section-pad-x);
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: padding 0.5s ease;
}

.nav.is-scrolled .nav__bar {
  padding: 16px var(--section-pad-x);
}

.nav__logo {
  z-index: 10001;
  position: relative;
}

.nav__logo img {
  height: 56px;
  width: auto;
  display: block;
  transition: height 0.5s ease;
}

.nav.is-scrolled .nav__logo img {
  height: 44px;
}

.nav__actions {
  display: flex;
  align-items: center;
  gap: 14px;
  z-index: 10001;
  position: relative;
}

.nav__contact-btn {
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  color: #fff;
  background: var(--color-accent);
  border-radius: 6px;
  padding: 11px 24px;
  letter-spacing: 0.02em;
  transition: background var(--transition-fast);
}

.nav__contact-btn:hover {
  background: var(--color-accent-hover);
}

.nav__menu-btn {
  font-family: var(--font-body);
  font-size: 13px;
  font-weight: 600;
  color: #fff;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 6px;
  padding: 11px 22px;
  display: flex;
  align-items: center;
  gap: 10px;
  letter-spacing: 0.02em;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.nav__menu-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.18);
}

.nav__burger {
  width: 18px;
  height: 12px;
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.nav__burger span {
  display: block;
  width: 100%;
  height: 1.5px;
  background: #fff;
  border-radius: 1px;
}

/* --- Overlay Menu --- */
.overlay {
  position: fixed;
  inset: 0;
  z-index: 10000;
  background: #0a0a0a;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.6s var(--ease-out), visibility 0.6s;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

.overlay.is-open {
  opacity: 1;
  visibility: visible;
}

.overlay__close {
  position: absolute;
  top: 28px;
  right: var(--section-pad-x);
  z-index: 10;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition-fast), border-color var(--transition-fast), transform var(--transition-fast);
}

.overlay__close:hover {
  background: rgba(215, 38, 30, 0.15);
  border-color: rgba(215, 38, 30, 0.3);
  transform: rotate(90deg);
}

.overlay__close svg {
  width: 18px;
  height: 18px;
  stroke: #fff;
  stroke-width: 1.5;
  stroke-linecap: round;
}

.overlay__grid {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 120px var(--section-pad-x) 80px;
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr;
  gap: 80px;
  min-height: 100vh;
  align-content: center;
}

/* Primary links */
.overlay__primary {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.overlay__link {
  font-family: var(--font-heading);
  font-size: 52px;
  font-weight: 300;
  color: rgba(255, 255, 255, 0.4);
  line-height: 1.15;
  padding: 10px 0;
  display: flex;
  align-items: baseline;
  gap: 16px;
  transition: color 0.4s ease, padding-left 0.5s var(--ease-out);
  transform: translateY(30px);
  opacity: 0;
}

.overlay.is-open .overlay__link {
  transform: translateY(0);
  opacity: 1;
}

.overlay.is-open .overlay__link:nth-child(1) { transition: color 0.4s, padding-left 0.5s ease, transform 0.6s var(--ease-out) 0.08s, opacity 0.6s ease 0.08s; }
.overlay.is-open .overlay__link:nth-child(2) { transition: color 0.4s, padding-left 0.5s ease, transform 0.6s var(--ease-out) 0.14s, opacity 0.6s ease 0.14s; }
.overlay.is-open .overlay__link:nth-child(3) { transition: color 0.4s, padding-left 0.5s ease, transform 0.6s var(--ease-out) 0.20s, opacity 0.6s ease 0.20s; }
.overlay.is-open .overlay__link:nth-child(4) { transition: color 0.4s, padding-left 0.5s ease, transform 0.6s var(--ease-out) 0.26s, opacity 0.6s ease 0.26s; }
.overlay.is-open .overlay__link:nth-child(5) { transition: color 0.4s, padding-left 0.5s ease, transform 0.6s var(--ease-out) 0.32s, opacity 0.6s ease 0.32s; }
.overlay.is-open .overlay__link:nth-child(6) { transition: color 0.4s, padding-left 0.5s ease, transform 0.6s var(--ease-out) 0.38s, opacity 0.6s ease 0.38s; }

.overlay__link:hover {
  color: #fff;
  padding-left: 14px;
}

.overlay__link-num {
  font-size: 12px;
  font-weight: 400;
  color: var(--color-accent);
  opacity: 0;
  transition: opacity var(--transition-fast);
  min-width: 20px;
}

.overlay__link:hover .overlay__link-num {
  opacity: 1;
}

/* Sub-nav columns */
.overlay__col {
  padding-top: 12px;
}

.overlay__col-heading {
  font-family: var(--font-heading);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 30px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.overlay__col-line {
  width: 16px;
  height: 1px;
  background: rgba(215, 38, 30, 0.35);
}

.overlay__sub-links {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.overlay__sub-link {
  font-family: var(--font-body);
  font-size: 15px;
  color: rgba(255, 255, 255, 0.5);
  transition: color var(--transition-fast), padding-left var(--transition-fast);
}

.overlay__sub-link:hover {
  color: #fff;
  padding-left: 6px;
}

.overlay__contact {
  margin-top: 36px;
  padding-top: 28px;
  border-top: 1px solid var(--color-border-light);
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.overlay__contact-link {
  font-family: var(--font-body);
  font-size: 14px;
  color: rgba(255, 255, 255, 0.25);
  transition: color var(--transition-fast);
}

.overlay__contact-link:hover {
  color: var(--color-accent);
}

/* --- Responsive --- */
@media (max-width: 900px) {
  .nav__bar { padding: 18px var(--section-pad-x-md); }
  .nav.is-scrolled .nav__bar { padding: 14px var(--section-pad-x-md); }
  .nav__logo img { height: 44px; }
  .nav.is-scrolled .nav__logo img { height: 38px; }
  .nav__contact-btn { display: none; }
  .overlay__grid {
    grid-template-columns: 1fr;
    gap: 36px;
    padding: 100px var(--section-pad-x-md) 60px;
    align-content: start;
  }

  /* Match primary links to sub-link style on mobile */
  .overlay__primary {
    gap: 0;
  }
  .overlay__link {
    font-size: 15px;
    font-family: var(--font-body);
    font-weight: 400;
    color: rgba(255, 255, 255, 0.5);
    padding: 10px 0;
    gap: 0;
  }
  .overlay__link:hover {
    padding-left: 6px;
  }
  .overlay__link-num {
    display: none;
  }

  .overlay__close { top: 20px; right: var(--section-pad-x-md); width: 42px; height: 42px; }
}

@media (max-width: 640px) {
  .nav__bar { padding: 18px var(--section-pad-x-sm); }
  .nav.is-scrolled .nav__bar { padding: 14px var(--section-pad-x-sm); }
  .nav__menu-btn { padding: 10px 16px; font-size: 12px; gap: 8px; }
  .nav__logo img { height: 38px; }
}