/* ==========================================================================
   layout.css — Grid, Containers, Header, Footer
   Breakpoints (Design-System-v1.md §6): sm 480 / md 768 / lg 1024 / xl 1280 / 2xl 1536
   Mobile-first: base styles target <480px, each query progressively enhances.
   ========================================================================== */

/* ---- Containers -------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-4);
}
@media (min-width: 768px) { .container { padding-inline: var(--space-5); } }
@media (min-width: 1024px) { .container { padding-inline: var(--space-6); } }

.container-narrow {
  width: 100%;
  max-width: var(--container-narrow);
  margin-inline: auto;
  padding-inline: var(--space-4);
}

/* ---- Section rhythm ----------------------------------------------------- */
.section { padding-block: var(--space-8); }
@media (min-width: 768px) { .section { padding-block: var(--space-9); } }

/* ---- Grid ---------------------------------------------------------------- */
.grid { display: grid; gap: var(--space-4); }
@media (min-width: 768px) { .grid { gap: var(--space-5); } }

.grid-2 { grid-template-columns: 1fr; }
.grid-3 { grid-template-columns: 1fr; }
.grid-4 { grid-template-columns: 1fr; }

@media (min-width: 768px) {
  .grid-2 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 1024px) {
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
  .grid-4 { grid-template-columns: repeat(4, 1fr); }
}

.stack { display: flex; flex-direction: column; gap: var(--space-4); }
.cluster { display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-3); }

/* ---- Site Header --------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky-header);
  background: var(--color-background);
  transition: box-shadow var(--transition-base);
}
.site-header.is-scrolled { box-shadow: var(--shadow-sm); }

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding-block: var(--space-4);
}

.site-nav { display: none; }
@media (min-width: 1024px) {
  .site-nav {
    display: flex;
    align-items: center;
    gap: var(--space-6);
  }
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-5);
}

.site-nav__link {
  font-size: var(--text-body-sm);
  font-weight: 600;
  color: var(--color-text-primary);
  padding-block: var(--space-2);
  border-bottom: 2px solid transparent;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}
.site-nav__link:hover { color: var(--color-accent-text); }
.site-nav__link[aria-current="page"] {
  border-bottom-color: var(--color-accent);
  color: var(--color-primary);
}

/* Services mega-menu (desktop) */
.has-submenu { position: relative; }
.submenu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 560px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: var(--space-5);
  display: none;
  gap: var(--space-5);
  z-index: var(--z-dropdown);
}
.has-submenu:hover .submenu,
.has-submenu:focus-within .submenu {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
}
.submenu__group .submenu-label { font-size: var(--text-label); text-transform: uppercase; letter-spacing: 0.04em; color: var(--color-text-muted); margin-bottom: var(--space-2); display: block; }
.submenu__group a { display: block; padding-block: var(--space-1); font-size: var(--text-body-sm); }
.submenu__group a:hover { color: var(--color-accent-text); }

/* Mobile nav toggle + panel */
.nav-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
}
@media (min-width: 1024px) { .nav-toggle { display: none; } }
.nav-toggle:hover { background: var(--color-border); }

.mobile-nav {
  position: fixed;
  inset: 0;
  z-index: var(--z-modal);
  background: var(--color-surface);
  padding: var(--space-5);
  overflow-y: auto;
  transform: translateX(100%);
  transition: transform var(--transition-base);
}
.mobile-nav.is-open { transform: translateX(0); }
@media (min-width: 1024px) { .mobile-nav { display: none; } }

.mobile-nav__header { display: flex; justify-content: space-between; align-items: center; margin-bottom: var(--space-6); }
.mobile-nav__list { display: flex; flex-direction: column; gap: var(--space-2); }
.mobile-nav__link { display: block; padding: var(--space-3) 0; font-size: var(--text-heading-sm); font-family: var(--font-display); border-bottom: 1px solid var(--color-border); }

/* ---- Site Footer ---------------------------------------------------------- */
.site-footer {
  background: var(--color-primary);
  color: var(--color-text-inverse);
  padding-block: var(--space-8);
}
.site-footer a { color: var(--color-text-inverse); opacity: 0.85; transition: opacity var(--transition-fast), color var(--transition-fast); }
.site-footer a:hover { opacity: 1; color: var(--color-accent); }

.footer-grid {
  display: grid;
  gap: var(--space-6);
  grid-template-columns: 1fr;
}
@media (min-width: 768px) { .footer-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1024px) { .footer-grid { grid-template-columns: 2fr 1fr 1fr 1fr; } }

.footer-grid .footer-label {
  font-size: var(--text-label);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-accent);
  margin-bottom: var(--space-3);
}
.footer-grid ul { display: flex; flex-direction: column; gap: var(--space-2); }
.footer-grid p { color: var(--color-text-inverse); opacity: 0.75; }

.footer-bottom {
  margin-top: var(--space-7);
  padding-top: var(--space-5);
  border-top: 1px solid rgba(248,250,252,0.15);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-3);
  font-size: var(--text-body-sm);
  opacity: 0.7;
}

/* ---- Breadcrumbs ----------------------------------------------------------- */
.breadcrumbs {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-body-sm);
  color: var(--color-text-muted);
  padding-block: var(--space-4);
}
.breadcrumbs a:hover { color: var(--color-accent-text); }
.breadcrumbs [aria-current="page"] { color: var(--color-text-primary); }
.breadcrumbs__sep { opacity: 0.5; }