/* ============================================================================
   Layout - containers, the 12-column grid, section rhythm, header, footer.
   ========================================================================= */

.container {
  inline-size: 100%;
  max-inline-size: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.container--narrow { max-inline-size: var(--container-narrow); }
.container--wide { max-inline-size: var(--container-wide); }
.container--flush { padding-inline: 0; }

/* ---------------------------------------------------------------- grid */

.grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--grid-gap);
}

@media (min-width: 768px) {
  .grid { grid-template-columns: repeat(12, 1fr); }
}

/* Column spans only exist at >=768 where the grid is 12 wide. */
@media (min-width: 768px) {
  .col-2 { grid-column: span 2; }
  .col-3 { grid-column: span 3; }
  .col-4 { grid-column: span 4; }
  .col-5 { grid-column: span 5; }
  .col-6 { grid-column: span 6; }
  .col-7 { grid-column: span 7; }
  .col-8 { grid-column: span 8; }
  .col-12 { grid-column: span 12; }
}

/*
 * Below 768 the grid above is four columns wide and the col-* spans do not
 * exist, so a form field marked .col-6 was not half-width - it was one of four
 * narrow columns. Six fields therefore packed four-across on a phone, with the
 * labels wrapping onto three lines above inputs barely wide enough to type in.
 *
 * Anything carrying a span class stacks to full width instead. Scoped to
 * elements that declare a span, so the plain four-column behaviour any other
 * .grid relies on is untouched.
 */
@media (max-width: 767.98px) {
  .grid > [class*="col-"] { grid-column: 1 / -1; }
}

/* Auto-fit card grids: 1-up phone, 2-up tablet, 3-up desktop, 4-up large. */
.cards {
  display: grid;
  gap: var(--grid-gap);
  grid-template-columns: 1fr;
}

@media (min-width: 576px) { .cards--2up { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 768px) { .cards { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 992px) { .cards--3up { grid-template-columns: repeat(3, 1fr); } }
@media (min-width: 1200px) {
  .cards { grid-template-columns: repeat(3, 1fr); }
  .cards--4up { grid-template-columns: repeat(4, 1fr); }
}
@media (min-width: 1440px) {
  .cards--6up { grid-template-columns: repeat(6, 1fr); }
}

/* ---------------------------------------------------------------- sections */

.section {
  position: relative;
  padding-block: var(--sec-y);
}

.section--alt { background: var(--ink-850); }
.section--tight { padding-block: calc(var(--sec-y) * .6); }
.section--statement { padding-block: calc(var(--sec-y) * 1.25); }
.section--flush-top { padding-block-start: 0; }
.section--flush-bottom { padding-block-end: 0; }

/* Split layouts: 5/7 text splits at >=992. */
.split {
  display: grid;
  gap: var(--s-8);
  grid-template-columns: 1fr;
}

@media (min-width: 992px) {
  .split {
    grid-template-columns: 5fr 7fr;
    gap: var(--s-11);
  }
  .split--7-5 { grid-template-columns: 7fr 5fr; }
  .split--half { grid-template-columns: 1fr 1fr; }
  .split__sticky {
    position: sticky;
    inset-block-start: calc(var(--header-h) + var(--s-8));
  }
}

/* ---------------------------------------------------------------- section head */

.section-head {
  display: flex;
  flex-direction: column;
  gap: var(--s-4);
  margin-block-end: var(--s-9);
}

@media (min-width: 768px) {
  .section-head--split {
    flex-direction: row;
    align-items: flex-end;
    justify-content: space-between;
    gap: var(--s-8);
  }
  .section-head--split .section-head__aside { flex-shrink: 0; }
}

.section-head__title { max-inline-size: 20ch; }

/* ---------------------------------------------------------------- header */

.site-header {
  position: fixed;
  inset-block-start: 0;
  inset-inline: 0;
  z-index: var(--z-header);
  block-size: var(--header-h);
  display: flex;
  align-items: center;
  padding-block-start: env(safe-area-inset-top, 0);
  background: transparent;
  border-block-end: 1px solid transparent;
  transition:
    background var(--t-base) var(--ease),
    block-size var(--t-base) var(--ease),
    border-color var(--t-base) var(--ease),
    transform var(--t-base) var(--ease);
}

.site-header.is-scrolled {
  background: rgba(11, 11, 12, .82);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border-block-end-color: var(--line);
}

@media (min-width: 1200px) {
  .site-header.is-scrolled { block-size: 72px; }
}

/* Hides on scroll-down past 600px, reveals on scroll-up. */
.site-header.is-hidden { transform: translateY(-100%); }

.site-header__inner {
  inline-size: 100%;
  max-inline-size: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-6);
}

.site-header__brand {
  display: inline-flex;
  align-items: center;
  flex-shrink: 0;
  color: var(--white);
}

.site-header__brand svg,
.site-header__brand img { block-size: 26px; inline-size: auto; }

@media (min-width: 768px) {
  .site-header__brand svg,
  .site-header__brand img { block-size: 30px; }
}

.site-header__actions {
  display: flex;
  align-items: center;
  gap: var(--s-4);
}

/* Body offset: pages that do not open with a full-bleed hero. */
.site-main { min-block-size: 60vh; }
.site-main--offset { padding-block-start: var(--header-h); }

/* ---------------------------------------------------------------- footer */

.site-footer {
  background: var(--ink-900);
  border-block-start: 1px solid var(--line);
  padding-block: var(--s-9) var(--s-7);
  padding-block-end: calc(var(--s-7) + env(safe-area-inset-bottom, 0px));
}

@media (min-width: 768px) {
  .site-footer { padding-block: var(--s-11) var(--s-7); }
}

.site-footer__top {
  display: grid;
  gap: var(--s-9);
  grid-template-columns: 1fr;
}

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

@media (min-width: 992px) {
  .site-footer__top {
    grid-template-columns: 4fr 8fr;
    gap: var(--s-11);
  }
}

.site-footer__columns {
  display: grid;
  gap: var(--s-7);
  grid-template-columns: 1fr;
}

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

@media (min-width: 992px) {
  .site-footer__columns { grid-template-columns: repeat(4, 1fr); }
}

.site-footer__bottom {
  margin-block-start: var(--s-9);
  padding-block-start: var(--s-6);
  border-block-start: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  gap: var(--s-3);
  font-size: var(--fs-small);
  color: var(--mist-600);
}

@media (min-width: 768px) {
  .site-footer__bottom {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }
}

.site-footer__bottom-right {
  display: flex;
  align-items: center;
  gap: var(--s-6);
}

/* ---------------------------------------------------------------- ultra-wide
   Beyond 1760 the container is already capped; the extra space simply becomes
   margin. Nothing stretches. */

@media (min-width: 1760px) {
  .container { max-inline-size: var(--container); }
  .container--wide { max-inline-size: var(--container-wide); }
}

/* ---------------------------------------------------------------- footer columns
   <details> accordions on mobile so they work with JS disabled; plain lists
   from 768 up, where main.js forces them open. */

.footer-col summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-block-size: var(--tap);
  cursor: pointer;
  list-style: none;
}

.footer-col summary::-webkit-details-marker { display: none; }

.footer-col summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--blue-400);
}

.footer-col[open] summary::after { content: "\2212"; }

.footer-col__list {
  list-style: none;
  padding: 0;
  margin: var(--s-3) 0 var(--s-5);
}

.footer-col__list li { margin-block-end: var(--s-3); }

.footer-col__list a {
  position: relative;
  font-size: 15px;
  color: var(--mist-200);
}

.footer-col__list a::after {
  content: "";
  position: absolute;
  inset-block-end: -2px;
  inset-inline: 0;
  block-size: 1px;
  background: var(--blue-500);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--t-fast) var(--ease);
}

.footer-col__list a:hover { color: var(--white); }
.footer-col__list a:hover::after { transform: scaleX(1); }

@media (min-width: 768px) {
  .footer-col summary { pointer-events: none; }
  .footer-col summary::after { display: none; }
  .footer-col__list { margin-block-end: 0; }
}

/*
 * Legal pages render on paper (body.is-light). The header is transparent by
 * default so it can float over the home page's dark hero, which left the white
 * wordmark and light nav invisible against white until the page was scrolled.
 * These pages get a solid paper header with dark type, and keep it when
 * scrolled - .is-scrolled would otherwise flip it back to near-black.
 */
.site-header--light,
.site-header--light.is-scrolled {
  background: var(--paper);
  border-block-end-color: var(--line-dark);
  color: var(--ink-on-paper);
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
}

.site-header--light .nav__link { color: var(--muted-on-paper); }

.site-header--light .nav__link:hover,
.site-header--light .nav__link:focus-visible,
.site-header--light .nav__link[aria-expanded="true"],
.site-header--light .nav__link[aria-current="page"] { color: var(--ink-on-paper); }