/* ==========================================================================
   Structural layout: background field, header, footer, main
   ========================================================================== */

/* --- Ambient background --- */
.bg-field {
  position: fixed;
  inset: 0;
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
  background:
    radial-gradient(1200px 600px at 80% -10%, var(--glow-blue), transparent 60%),
    radial-gradient(900px 500px at 0% 100%, var(--glow-red), transparent 55%),
    var(--bg);
}
.bg-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.5;
}
.bg-glow--red {
  width: 500px; height: 500px;
  top: -120px; right: -80px;
  background: radial-gradient(circle, var(--glow-red), transparent 70%);
  animation: drift 22s var(--ease) infinite alternate;
}
.bg-glow--blue {
  width: 620px; height: 620px;
  bottom: -220px; left: -140px;
  background: radial-gradient(circle, var(--glow-blue), transparent 70%);
  animation: drift 28s var(--ease) infinite alternate-reverse;
}
.bg-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(ellipse 100% 70% at 50% 0%, #000 20%, transparent 80%);
  -webkit-mask-image: radial-gradient(ellipse 100% 70% at 50% 0%, #000 20%, transparent 80%);
}

/* --- Header --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  height: var(--header-h);
  display: flex;
  align-items: center;
  background: transparent;
  transition: background var(--transition), border-color var(--transition), backdrop-filter var(--transition);
  border-bottom: 1px solid transparent;
}
.site-header.is-scrolled {
  background: var(--header-scrolled-bg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom-color: var(--border);
}
.header-inner {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--sp-5);
  display: flex;
  align-items: center;
  gap: var(--sp-5);
}
.brand {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  font-weight: 700;
  color: var(--text);
  letter-spacing: var(--ls-tight);
}
.brand__mark { width: 38px; height: 38px; flex-shrink: 0; }
.brand__text { display: flex; flex-direction: column; line-height: 1.1; }
.brand__text small {
  font-size: var(--fs-xs);
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: var(--ls-wide);
  text-transform: uppercase;
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--sp-1);
  margin-left: auto;
}
.nav__link {
  position: relative;
  padding: var(--sp-2) var(--sp-3);
  font-size: var(--fs-sm);
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background var(--transition-fast);
}
.nav__link:hover { color: var(--text); background: var(--surface); }
.nav__link.is-active { color: var(--text); }
.nav__link.is-active::after {
  content: "";
  position: absolute;
  left: var(--sp-3); right: var(--sp-3);
  bottom: 2px;
  height: 2px;
  background: var(--primary);
  border-radius: var(--radius-pill);
}
.nav__divider {
  width: 1px;
  height: 22px;
  background: var(--border-strong);
  margin-inline: var(--sp-2);
}
.nav__group { display: flex; align-items: center; gap: var(--sp-1); }

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  width: 42px; height: 42px;
  border-radius: var(--radius-sm);
  color: var(--text);
  margin-left: auto;
}
.nav-toggle:hover { background: var(--surface); }

/* --- Main --- */
.app-main {
  min-height: calc(100vh - var(--header-h));
  animation: page-in var(--transition-slow);
}

/* --- Footer --- */
.site-footer {
  border-top: 1px solid var(--border);
  background: var(--bg-alt);
  margin-top: var(--sp-9);
}
.footer-inner {
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--sp-7) var(--sp-5) var(--sp-6);
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: var(--sp-6);
}
.footer-brand { max-width: 320px; }
.footer-brand p { color: var(--text-muted); font-size: var(--fs-sm); margin-top: var(--sp-3); }
.footer-col h4 {
  font-size: var(--fs-xs);
  text-transform: uppercase;
  letter-spacing: var(--ls-caps);
  color: var(--text-muted);
  margin-bottom: var(--sp-3);
}
.footer-col a {
  display: block;
  padding: var(--sp-1) 0;
  color: var(--text-secondary);
  font-size: var(--fs-sm);
}
.footer-col a:hover { color: var(--gold); }
.footer-bottom {
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--sp-4) var(--sp-5);
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--sp-4);
  color: var(--text-muted);
  font-size: var(--fs-xs);
}

/* --- Responsive --- */
@media (max-width: 860px) {
  .footer-inner { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 760px) {
  .nav-toggle { display: flex; align-items: center; justify-content: center; }
  .nav {
    position: fixed;
    inset: var(--header-h) 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: var(--sp-1);
    padding: var(--sp-4);
    margin: 0;
    background: var(--nav-mobile-bg);
    backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border);
    transform: translateY(-12px);
    opacity: 0;
    pointer-events: none;
    transition: transform var(--transition), opacity var(--transition);
  }
  .nav.is-open { transform: translateY(0); opacity: 1; pointer-events: auto; }
  .nav__link { padding: var(--sp-3) var(--sp-4); }
  .nav__divider { width: auto; height: 1px; margin: var(--sp-2) 0; }
  .nav__group { flex-direction: column; align-items: stretch; }
}
@media (max-width: 560px) {
  .footer-inner { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
}