/* =========================================================
   Header / Nav / Footer — shared layout
   ========================================================= */

/* === Header === */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: var(--sp-6) 0;
  transition: background var(--t-med) var(--ease), padding var(--t-med) var(--ease);
  color: var(--paper);
}
/* Subtle top-down gradient for legibility over hero images */
.site-header::before {
  content: '';
  position: absolute;
  inset: 0;
  bottom: -2rem;
  background: linear-gradient(180deg, rgba(14,14,14,0.55) 0%, rgba(14,14,14,0) 100%);
  z-index: -1;
  pointer-events: none;
  transition: opacity var(--t-med) var(--ease);
}
.site-header.solid {
  background: rgba(14, 14, 14, 0.92);
  backdrop-filter: blur(20px) saturate(140%);
  -webkit-backdrop-filter: blur(20px) saturate(140%);
  padding: var(--sp-4) 0;
}
.site-header.solid::before { opacity: 0; }
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-8);
}
.nav-brand {
  display: inline-flex;
  align-items: center;
  height: 96px;
  transition: opacity var(--t-fast) var(--ease);
}
.nav-brand:hover { opacity: 0.78; }
.nav-brand img {
  height: 100%;
  width: auto;
  display: block;
  /* Logo is black on transparent — convert to pure white for dark headers */
  filter: brightness(0) invert(1) drop-shadow(0 1px 12px rgba(0,0,0,0.45));
}
.site-header.solid .nav-brand { height: 72px; }
@media (max-width: 600px) {
  .nav-brand { height: 72px; }
  .site-header.solid .nav-brand { height: 56px; }
}
.nav-list {
  display: flex;
  gap: var(--sp-8);
  align-items: center;
}
.nav-link {
  font-size: var(--fs-body-sm);
  font-weight: 400;
  letter-spacing: 0.02em;
  position: relative;
  padding: var(--sp-2) 0;
  transition: opacity var(--t-fast) var(--ease);
}
.nav-link::after {
  content: '';
  position: absolute;
  left: 0; right: 0;
  bottom: 0;
  height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: right;
  transition: transform var(--t-med) var(--ease);
}
.nav-link:hover::after,
.nav-link.active::after {
  transform: scaleX(1);
  transform-origin: left;
}
.nav-cta {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: var(--sp-3) var(--sp-6);
  border: 1px solid currentColor;
  border-radius: 999px;
  transition: all var(--t-fast) var(--ease);
}
.nav-cta:hover {
  background: var(--paper);
  color: var(--ink);
}
.nav-mobile-toggle {
  display: none;
  width: 3rem;
  height: 3rem;
  position: relative;
  z-index: 102;
}
.nav-mobile-toggle span {
  position: absolute;
  left: 0.625rem;
  right: 0.625rem;
  height: 2px;
  background: currentColor;
  transition: all 300ms var(--ease);
  border-radius: 1px;
}
.nav-mobile-toggle span:nth-child(1) { top: 1.15rem; }
.nav-mobile-toggle span:nth-child(2) { top: 1.65rem; }
.nav-mobile-toggle[aria-expanded="true"] span:nth-child(1) { top: 1.4rem; transform: rotate(45deg); }
.nav-mobile-toggle[aria-expanded="true"] span:nth-child(2) { top: 1.4rem; transform: rotate(-45deg); }

@media (max-width: 880px) {
  .nav-list { display: none; }
  .nav-mobile-toggle { display: block; }
  .nav-list.open {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: var(--sp-4);
    position: fixed;
    inset: 0;
    background: var(--ink);
    color: var(--paper);
    padding: 7rem var(--gutter) var(--sp-12);
    font-size: var(--fs-h4);
    font-family: var(--font-display);
    z-index: 101;
    overflow-y: auto;
  }
  .nav-list.open .nav-link { font-size: 2rem; padding: var(--sp-3) 0; width: 100%; border-bottom: 1px solid rgba(255,255,255,0.08); }
  .nav-list.open .nav-link::after { display: none; }
  .nav-list.open .nav-cta { font-size: 0.85rem; margin-top: var(--sp-4); display: inline-flex; padding: var(--sp-4) var(--sp-6); }
}

/* === Footer === */
.site-footer {
  background: var(--ink);
  color: var(--linen);
  padding: var(--sp-32) 0 var(--sp-12);
  position: relative;
  overflow: hidden;
}
.site-footer::before {
  content: 'ATIS';
  position: absolute;
  left: -1.5vw;
  bottom: -6vw;
  font-family: var(--font-display);
  font-size: 36vw;
  font-weight: 800;
  font-variation-settings: 'opsz' 144;
  letter-spacing: -0.05em;
  color: rgba(255, 255, 255, 0.03);
  line-height: 0.8;
  pointer-events: none;
  z-index: 0;
}
.footer-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: var(--sp-12);
  align-items: start;
}
@media (max-width: 880px) {
  .footer-grid { grid-template-columns: 1fr 1fr; gap: var(--sp-12); }
  .footer-grid > :first-child { grid-column: 1 / -1; }
}
.footer-brand-block .fr-display { font-size: clamp(2.5rem, 5vw, 4rem); margin-bottom: var(--sp-4); }
.footer-brand-block p { color: var(--stone); max-width: 32ch; font-size: var(--fs-body-sm); line-height: 1.6; }
.footer-col h6 {
  font-family: var(--font-mono);
  font-size: var(--fs-overline);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--sand);
  margin-bottom: var(--sp-4);
  font-weight: 500;
}
.footer-col ul li { margin-bottom: var(--sp-3); }
.footer-col a {
  color: var(--linen);
  transition: color var(--t-fast) var(--ease);
  font-size: var(--fs-body-sm);
}
.footer-col a:hover { color: var(--ember-soft); }
.footer-bottom {
  position: relative;
  z-index: 1;
  margin-top: var(--sp-24);
  padding-top: var(--sp-6);
  border-top: 1px solid rgba(255,255,255,0.08);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  color: var(--stone);
  flex-wrap: wrap;
  gap: var(--sp-3);
}
.site-footer { padding: var(--sp-24) 0 var(--sp-8); }
.site-footer::before { font-size: 50vw; bottom: -10vw; }
@media (max-width: 600px) {
  .footer-bottom { flex-direction: column; gap: var(--sp-4); text-align: center; }
}