/* ============================================================================
   layout.css  —  header, footer, grid utilities, section rhythm
   ----------------------------------------------------------------------------
   Structural styles only. No brand colours beyond tokens. No component
   specifics — those live in components.css.
============================================================================ */

/* ---- Container --------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.container--wide { max-width: var(--container-wide); }
.container--measure { max-width: var(--container-measure); }

/* ---- Section rhythm --------------------------------------------------- */
.section {
  padding-block: var(--section-py);
}
.section--large { padding-block: var(--section-py-large); }
.section--tight { padding-block: calc(var(--section-py) * 0.6); }

.section--alt { background: var(--color-bg-alt); }
.section--ink {
  background: var(--color-ink);
  color: var(--color-paper);
}
.section--ink a:not(.btn) { color: var(--color-accent); }
.section--ink h1, .section--ink h2, .section--ink h3,
.section--ink h4, .section--ink h5, .section--ink h6 { color: inherit; }

/* ---- Stack: vertical spacing between children ------------------------- */
.stack > * + * { margin-top: var(--stack-gap, var(--space-4)); }
.stack--tight { --stack-gap: var(--space-2); }
.stack--loose { --stack-gap: var(--space-6); }
.stack--xl    { --stack-gap: var(--space-8); }

/* ---- Cluster: horizontal row with wrap -------------------------------- */
.cluster {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  align-items: center;
}
.cluster--tight { gap: var(--space-2); }
.cluster--end { justify-content: flex-end; }
.cluster--between { justify-content: space-between; }

/* ---- Grid utilities --------------------------------------------------- */
.grid {
  display: grid;
  gap: var(--space-5);
}
.grid--2 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 18rem), 1fr)); }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 16rem), 1fr)); }
.grid--4 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 13rem), 1fr)); }

@media (min-width: 40em) { /* 640px */
  .grid--2-sm { grid-template-columns: repeat(2, 1fr); }
  .grid--3-sm { grid-template-columns: repeat(3, 1fr); }
}
@media (min-width: 60em) { /* 960px */
  .grid--2-md { grid-template-columns: repeat(2, 1fr); }
  .grid--3-md { grid-template-columns: repeat(3, 1fr); }
  .grid--4-md { grid-template-columns: repeat(4, 1fr); }
}

/* Asymmetric two-column (main + rail) */
.grid--main-rail {
  display: grid;
  gap: var(--space-7);
}
@media (min-width: 60em) {
  .grid--main-rail { grid-template-columns: minmax(0, 2.1fr) minmax(0, 1fr); }
}

/* ---- Header ----------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background: color-mix(in srgb, var(--color-paper) 92%, transparent);
  backdrop-filter: saturate(150%) blur(10px);
  -webkit-backdrop-filter: saturate(150%) blur(10px);
  border-bottom: 1px solid var(--color-border);
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-5);
  min-height: var(--header-height);
  padding-block: var(--space-2);
}
@media (min-width: 60em) {
  .site-header__inner { min-height: var(--header-height-lg); }
}

.site-header__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-weight: var(--font-weight-bold);
  font-size: var(--step-1);
  color: var(--color-fg);
  text-decoration: none;
  letter-spacing: -0.01em;
}
.site-header__brand:hover { color: var(--color-fg); }
.site-header__brand-mark {
  width: 1.75rem;
  height: 1.75rem;
  background: var(--color-accent);
  color: var(--color-accent-ink);
  display: inline-grid;
  place-items: center;
  border-radius: var(--radius-2);
  font-weight: var(--font-weight-bold);
}

/* ---- Primary nav ------------------------------------------------------ */
.primary-nav {
  display: none;
}
@media (min-width: 60em) {
  .primary-nav {
    display: flex;
    align-items: center;
    gap: var(--space-2);
  }
}
.primary-nav__list {
  display: flex;
  gap: var(--space-1);
  list-style: none;
  padding: 0;
  margin: 0;
}
.primary-nav__link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-2);
  color: var(--color-fg);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  font-size: var(--step-0);
  background: transparent;
  border: none;
  cursor: pointer;
  transition: background var(--duration-fast) var(--ease-standard),
              color var(--duration-fast) var(--ease-standard);
}
.primary-nav__link:hover {
  background: var(--color-paper-soft);
  color: var(--color-fg);
}
.primary-nav__link[aria-expanded="true"] {
  background: var(--color-paper-soft);
  color: var(--color-accent);
  box-shadow: inset 0 -2px 0 var(--color-accent);
}
.primary-nav__link[aria-current="page"] {
  color: var(--color-accent);
}
.primary-nav__chevron {
  width: 0.75rem;
  height: 0.75rem;
  transition: transform var(--duration-fast) var(--ease-standard);
}
.primary-nav__link[aria-expanded="true"] .primary-nav__chevron {
  transform: rotate(180deg);
}

/* ---- Dropdown (mega-menu on wide screens, accordion on narrow) -------- */
.primary-nav__item { position: relative; }
.primary-nav__panel {
  display: none;
  position: absolute;
  top: calc(100% + var(--space-2));
  left: 50%;
  transform: translateX(-50%);
  min-width: 18rem;
  background: var(--color-paper);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-3);
  box-shadow: var(--shadow-3);
  padding: var(--space-5);
  z-index: var(--z-dropdown);
}
/* Caret arrow connecting panel to trigger */
.primary-nav__panel::before {
  content: "";
  position: absolute;
  top: -0.5rem;
  left: 50%;
  transform: translateX(-50%);
  width: 1rem;
  height: 0.5rem;
  background: var(--color-paper);
  clip-path: polygon(50% 0%, 0% 100%, 100% 100%);
  border-top: 1px solid var(--color-border);
  filter: drop-shadow(0 -1px 0 var(--color-border));
}
.primary-nav__panel[data-open="true"] {
  display: block;
}
/* Wide panels (Solutions, Platform) span multiple columns */
.primary-nav__panel--wide {
  min-width: min(90vw, 44rem);
}
.primary-nav__panel--xwide {
  min-width: min(90vw, 56rem);
}

.primary-nav__section { margin-bottom: var(--space-5); }
.primary-nav__section:last-child { margin-bottom: 0; }
.primary-nav__section-label {
  display: block;
  font-size: var(--step--1);
  font-weight: var(--font-weight-semi);
  color: var(--color-fg-quiet);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--space-2);
}
.primary-nav__section-grid {
  display: grid;
  gap: var(--space-1);
}
@media (min-width: 40em) {
  .primary-nav__panel--wide .primary-nav__section-grid { grid-template-columns: 1fr 1fr; }
  .primary-nav__panel--xwide .primary-nav__section-grid { grid-template-columns: 1fr 1fr 1fr; }
}
.primary-nav__panel a {
  display: block;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-2);
  color: var(--color-fg);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
}
.primary-nav__panel a:hover {
  background: var(--color-paper-soft);
  color: var(--color-accent);
}
.primary-nav__panel a small {
  display: block;
  color: var(--color-fg-quiet);
  font-weight: var(--font-weight-regular);
  margin-top: 2px;
}

/* ---- Header trailing actions ------------------------------------------ */
.site-header__actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* ---- Mobile nav toggle ------------------------------------------------ */
.nav-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-2);
  color: var(--color-fg);
  cursor: pointer;
}
@media (min-width: 60em) {
  .nav-toggle { display: none; }
}

/* Mobile nav drawer */
.mobile-nav {
  display: none;
  border-top: 1px solid var(--color-border);
  background: var(--color-paper);
  padding: var(--space-5) var(--gutter);
}
.mobile-nav[data-open="true"] { display: block; }
@media (min-width: 60em) {
  .mobile-nav, .mobile-nav[data-open="true"] { display: none; }
}

.mobile-nav__group {
  border-bottom: 1px solid var(--color-border);
  padding-block: var(--space-3);
}
.mobile-nav__group:last-of-type { border-bottom: none; }
.mobile-nav__group-label {
  display: block;
  font-weight: var(--font-weight-semi);
  font-size: var(--step-0);
  margin-bottom: var(--space-2);
  color: var(--color-fg);
}
.mobile-nav__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--space-1);
}
.mobile-nav__list a {
  display: block;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-2);
  color: var(--color-fg);
  text-decoration: none;
}
.mobile-nav__list a:hover { background: var(--color-paper-soft); color: var(--color-accent); }
.mobile-nav__sublabel {
  display: block;
  margin: var(--space-3) 0 var(--space-1);
  font-size: var(--step--1);
  color: var(--color-fg-quiet);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ---- Footer ----------------------------------------------------------- */
.site-footer {
  background: var(--color-ink);
  color: var(--color-paper);
  padding-block: var(--space-9) var(--space-6);
  margin-top: var(--space-10);
}
.site-footer a { color: var(--color-paper); text-decoration: none; }
.site-footer a:hover { color: var(--color-accent); text-decoration: underline; }

.site-footer__grid {
  display: grid;
  gap: var(--space-7);
  grid-template-columns: 1fr;
}
@media (min-width: 40em) {
  .site-footer__grid { grid-template-columns: 1fr 1fr; }
}
@media (min-width: 60em) {
  .site-footer__grid { grid-template-columns: 1.2fr 1fr 1fr 1fr 1fr; }
}

.site-footer__brand-col p {
  color: color-mix(in srgb, var(--color-paper) 70%, transparent);
  max-width: 30ch;
}

.site-footer__heading {
  font-size: var(--step--1);
  font-weight: var(--font-weight-semi);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: color-mix(in srgb, var(--color-paper) 60%, transparent);
  margin-bottom: var(--space-4);
}
.site-footer__list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: var(--space-2);
}

.site-footer__bottom {
  margin-top: var(--space-8);
  padding-top: var(--space-5);
  border-top: 1px solid color-mix(in srgb, var(--color-paper) 15%, transparent);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-4);
  color: color-mix(in srgb, var(--color-paper) 60%, transparent);
  font-size: var(--step--1);
}
.site-footer__legal-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  list-style: none;
  margin: 0;
  padding: 0;
}

/* ---- Page-level structures ------------------------------------------- */
.page-hero {
  padding-block: var(--section-py-large) var(--section-py);
}
.page-hero__eyebrow {
  color: var(--color-accent);
  font-weight: var(--font-weight-semi);
  font-size: var(--step-0);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--space-3);
  display: block;
}
.page-hero__title {
  font-size: var(--step-6);
  max-width: 18ch;
  margin-bottom: var(--space-5);
}
.page-hero__lede {
  font-size: var(--step-2);
  color: var(--color-fg-muted);
  max-width: 55ch;
  margin-bottom: var(--space-6);
  line-height: var(--line-height-snug);
}

/* ---- Breadcrumb ------------------------------------------------------- */
.breadcrumb {
  font-size: var(--step--1);
  color: var(--color-fg-quiet);
  margin-bottom: var(--space-5);
}
.breadcrumb ol {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}
.breadcrumb li + li::before {
  content: "/";
  margin-right: var(--space-2);
  color: var(--color-border-strong);
}
.breadcrumb a {
  color: inherit;
  text-decoration: none;
}
.breadcrumb a:hover { color: var(--color-accent); }
.breadcrumb [aria-current="page"] { color: var(--color-fg); }