/* ==========================================================================
   Layout: containers, header, navigation, sections, page header, footer
   ========================================================================== */

/* ---- Containers --------------------------------------------------------- */

.container {
  width: 100%;
  max-width: calc(var(--container-max) + var(--gutter) * 2);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.container--narrow {
  max-width: calc(var(--container-narrow) + var(--gutter) * 2);
}

/* ---- Sections ----------------------------------------------------------- */

.section {
  padding-block: var(--section-space);
}

.section--tight {
  padding-block: var(--space-8);
}

.section--sunken {
  background: var(--cream-sunken);
  border-block: var(--border-width) solid var(--line);
}

/* Two plain sections in a row share one gap instead of doubling it. */
.section:not(.section--sunken) + .section:not(.section--sunken) {
  padding-top: 0;
}

/* Heading block at the top of a section. */
.section-head {
  display: grid;
  gap: var(--space-3);
  max-width: 40rem;
  margin-bottom: var(--space-6);
}

.section-head__text {
  color: var(--color-text-muted);
  font-size: var(--text-lg);
  line-height: var(--leading-lg);
}

/* Split row: heading/text on one side, content on the other. */
.split {
  display: grid;
  gap: var(--space-6);
}

@media (min-width: 64em) {
  .split {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: var(--space-8);
    align-items: start;
  }

  .split--even {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }

  .split--sticky > :first-child {
    position: sticky;
    top: var(--space-6);
  }
}

.stack > * + * {
  margin-top: var(--space-4);
}

.stack-lg > * + * {
  margin-top: var(--space-5);
}

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

.site-header {
  position: relative;
  z-index: 20;
  background: var(--cream);
  border-bottom: var(--border-width) solid var(--green-dark);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-5);
  min-height: var(--header-height);
  padding-block: var(--space-3);
}

/* ---- Brand ---------------------------------------------------------------- */

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  color: var(--ink);
  font-size: var(--text-xl);
  font-weight: var(--weight-heavy);
  letter-spacing: -0.01em;
  line-height: 1;
  text-decoration: none;
}

.brand:hover {
  color: var(--ink);
}

.brand .px-icon {
  width: 32px;
  height: 32px;
  transition: transform var(--duration-fast) var(--ease-out);
}

.brand:hover .px-icon {
  transform: translateY(-2px);
}

.brand:active .px-icon {
  transform: translateY(1px);
}

.brand__name {
  padding-bottom: 2px;
  border-bottom: 3px solid transparent;
  transition: border-color var(--duration-fast) var(--ease-out);
}

.brand:hover .brand__name {
  border-bottom-color: var(--amber);
}

.brand--on-dark,
.brand--on-dark:hover {
  color: var(--on-dark);
}

/* ---- Primary navigation ---------------------------------------------------- */

.site-nav__list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav__link {
  position: relative;
  display: inline-flex;
  align-items: center;
  min-height: 2.75rem;
  padding: var(--space-2) var(--space-3);
  color: var(--ink);
  font-weight: var(--weight-bold);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition:
    background-color var(--duration-fast) var(--ease-out),
    color var(--duration-fast) var(--ease-out);
}

/* Block underline marker, shared by hover and current states. */
.site-nav__link::after {
  content: '';
  position: absolute;
  left: var(--space-3);
  right: var(--space-3);
  bottom: 4px;
  height: 4px;
  background: var(--amber);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--duration-fast) var(--ease-out);
}

.site-nav__link:hover {
  color: var(--ink);
  background: var(--cream-sunken);
}

.site-nav__link:hover::after {
  transform: scaleX(1);
}

.site-nav__link:active {
  background: var(--line);
}

.site-nav__link[aria-current='page']::after {
  background: var(--green);
  transform: scaleX(1);
}

/* Menu toggle: only rendered as a control when JS is available. */
.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--space-2);
  min-height: 2.75rem;
  padding: var(--space-2) var(--space-4);
  background: var(--cream-raised);
  color: var(--ink);
  font-weight: var(--weight-bold);
  border: var(--border-width) solid var(--green-dark);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-primary-active);
  transition:
    transform var(--duration-fast) var(--ease-out),
    box-shadow var(--duration-fast) var(--ease-out),
    background-color var(--duration-fast) var(--ease-out);
}

.nav-toggle:hover {
  background: var(--cream-sunken);
  transform: translateY(-1px);
  box-shadow: 0 3px 0 var(--green-dark);
}

.nav-toggle:active {
  transform: translateY(var(--depth-1));
  box-shadow: none;
}

.nav-toggle[aria-expanded='true'] {
  background: var(--green-dark);
  color: var(--on-dark);
}

/* Three pixel bars that become a cross. */
.nav-toggle__icon {
  position: relative;
  width: 16px;
  height: 12px;
}

.nav-toggle__icon::before,
.nav-toggle__icon::after,
.nav-toggle__bar {
  content: '';
  position: absolute;
  left: 0;
  width: 16px;
  height: 2px;
  background: currentColor;
  transition:
    transform var(--duration-fast) var(--ease-out),
    opacity var(--duration-fast) var(--ease-out);
}

.nav-toggle__icon::before {
  top: 0;
}

.nav-toggle__bar {
  top: 5px;
}

.nav-toggle__icon::after {
  top: 10px;
}

.nav-toggle[aria-expanded='true'] .nav-toggle__icon::before {
  transform: translateY(5px) rotate(45deg);
}

.nav-toggle[aria-expanded='true'] .nav-toggle__bar {
  opacity: 0;
}

.nav-toggle[aria-expanded='true'] .nav-toggle__icon::after {
  transform: translateY(-5px) rotate(-45deg);
}

@media (max-width: 47.99em) {
  /* Without JS the links simply wrap under the brand. */
  .site-nav {
    width: 100%;
  }

  .site-nav__list {
    margin-inline: calc(var(--space-3) * -1);
  }

  .js .nav-toggle {
    display: inline-flex;
  }

  .js .site-nav {
    display: none;
    padding-bottom: var(--space-3);
  }

  .js .site-nav.is-open {
    display: block;
  }

  .js .site-nav__list {
    flex-direction: column;
    gap: 0;
    margin-inline: 0;
    border-top: var(--border-width) solid var(--line);
  }

  .js .site-nav__list li {
    border-bottom: var(--border-width) solid var(--line);
  }

  .js .site-nav__link {
    display: flex;
    width: 100%;
    min-height: 3.25rem;
    padding-inline: var(--space-2);
    font-size: var(--text-lg);
    border-radius: 0;
  }

  .js .site-nav__link::after {
    left: 0;
    right: auto;
    top: var(--space-3);
    bottom: var(--space-3);
    width: 4px;
    height: auto;
    transform: scaleY(0);
    transform-origin: top;
  }

  .js .site-nav__link:hover::after,
  .js .site-nav__link[aria-current='page']::after {
    transform: scaleY(1);
  }

  .js .site-nav__link:hover,
  .js .site-nav__link[aria-current='page'] {
    padding-left: var(--space-4);
  }
}

/* ---- Page header (non-home pages) --------------------------------------- */

.page-header {
  padding-block: var(--space-7) var(--space-8);
  border-bottom: var(--border-width) solid var(--line);
}

.page-header__inner {
  display: grid;
  justify-items: start;
  gap: var(--space-4);
}

.page-header__inner > * {
  max-width: 48rem;
}

.page-header__lead {
  color: var(--color-text-muted);
  font-size: var(--text-lg);
  line-height: var(--leading-lg);
  max-width: 42rem;
}

.page-header__meta {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

@media (min-width: 48em) {
  .page-header {
    padding-block: var(--space-8) var(--space-9);
  }

  .page-header h1 {
    font-size: var(--text-hero);
    line-height: var(--leading-hero);
    letter-spacing: var(--tracking-hero);
  }
}

/* ---- Two-column page body with side rail ------------------------------- */

.with-rail {
  display: grid;
  /* minmax(0, …) keeps wide tables and code inside the column on phones. */
  grid-template-columns: minmax(0, 1fr);
  gap: var(--space-7);
}

@media (min-width: 64em) {
  .with-rail {
    grid-template-columns: minmax(0, 1fr) 16rem;
    gap: var(--space-9);
    align-items: start;
  }

  .with-rail--left {
    grid-template-columns: 14rem minmax(0, 1fr);
  }

  .with-rail__rail {
    position: sticky;
    top: var(--space-6);
  }
}

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

.site-footer {
  position: relative;
  padding-block: var(--space-8) var(--space-6);
  background: var(--green-dark);
  color: var(--on-dark-muted);
  font-size: var(--text-sm);
  line-height: var(--leading-sm);
}

/* Stepped block edge along the top of the footer. */
.site-footer::before {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: 100%;
  height: 12px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='96' height='12' shape-rendering='crispEdges'%3E%3Cpath fill='%23283618' d='M0 6h12v6H0zM12 0h12v12H12zM24 6h24v6H24zM48 0h24v12H48zM72 6h12v6H72zM84 0h12v12H84z'/%3E%3C/svg%3E");
  background-size: 96px 12px;
  background-repeat: repeat-x;
}

.site-footer :focus-visible {
  outline-color: var(--color-focus-on-dark);
}

.site-footer__grid {
  display: grid;
  gap: var(--space-7);
}

@media (min-width: 48em) {
  .site-footer__grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.4fr);
  }
}

.site-footer__brand {
  display: grid;
  gap: var(--space-4);
  align-content: start;
  max-width: 22rem;
}

.site-footer__nav {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(9rem, 1fr));
  gap: var(--space-6);
}

.footer-group__heading {
  margin-bottom: var(--space-3);
  color: var(--amber);
  font-size: var(--text-xs);
  line-height: var(--leading-xs);
  letter-spacing: var(--tracking-xs);
  text-transform: uppercase;
  font-weight: var(--weight-bold);
}

.footer-group__list {
  display: grid;
  gap: var(--space-1);
  margin: 0;
  padding: 0;
  list-style: none;
}

.footer-group__list a {
  display: inline-block;
  padding-block: var(--space-1);
  color: var(--on-dark);
  font-weight: var(--weight-medium);
  text-decoration-color: transparent;
}

.footer-group__list a:hover {
  color: var(--on-dark);
  text-decoration-color: var(--amber);
}

.site-footer__bottom {
  display: grid;
  gap: var(--space-2);
  margin-top: var(--space-8);
  padding-top: var(--space-5);
  border-top: var(--border-thin) solid rgb(254 250 224 / 0.18);
}

@media (min-width: 48em) {
  .site-footer__bottom {
    grid-template-columns: auto 1fr;
    gap: var(--space-5);
  }

  .site-footer__bottom p:last-child {
    text-align: right;
  }
}