.posts-intro__copy {
  width: min(526px, 100%);
  letter-spacing: -0.3px;
}

.posts-page {
  --posts-date-sticky-top: var(--space-2xl);

  overflow: visible;
}

.posts-page em {
  font-family: var(--font-family-display-italic);
  font-style: italic;
}

.posts-page.has-post-reveal-motion .posts-intro > *,
.posts-page.has-post-reveal-motion .post-row {
  opacity: 0;
  transform: translateY(8px);
  transition:
    opacity 520ms var(--ease-out),
    transform 520ms var(--ease-out);
}

.posts-page.has-post-reveal-motion
  .posts-intro.is-reveal-visible
  > *,
.posts-page.has-post-reveal-motion .post-row.is-reveal-visible {
  opacity: 1;
  transform: translateY(0);
}

.posts-page.has-post-reveal-motion
  .posts-intro.is-reveal-visible
  .posts-intro__copy {
  transition-delay: 60ms;
}

.posts-page.has-post-reveal-motion .post-row.is-reveal-visible {
  transition-delay: var(--post-reveal-delay, 0ms);
}

.posts-content {
  position: relative;
  display: grid;
  grid-template-columns: var(--page-grid-columns);
  column-gap: var(--grid-gap);
  align-items: start;
  padding-inline: var(--page-gutter);
}

.post-list,
.post-year-group__months,
.post-month-group__posts {
  margin: 0;
  padding: 0;
  list-style: none;
}

.post-list {
  --post-date-rail-width: 110px;
  --post-month-slot-width: 30px;
  --post-date-edge-inset: var(--space-xl);
  --post-date-pair-gap: 6px;
  --post-date-row-offset: var(--space-sm);

  grid-column: 1 / -1;
  grid-row: 1;
  display: flex;
  width: 100%;
  min-width: 0;
  flex-direction: column;
  gap: var(--space-xl);
}

.post-year-group,
.post-month-group {
  min-width: 0;
}

.post-year-group__layout,
.post-month-group__layout,
.post-row {
  display: grid;
  grid-template-columns: var(--page-grid-columns);
  column-gap: var(--grid-gap);
}

.post-year-group__layout {
  align-items: start;
}

.post-year-group__months,
.post-month-group__posts {
  display: flex;
  min-width: 0;
  flex-direction: column;
  gap: var(--space-xl);
}

.post-year-group__months {
  grid-column: 1 / -1;
  grid-row: 1;
}

.post-month-group__layout {
  align-items: start;
}

.post-month-group__posts {
  grid-column: 1 / -1;
  grid-row: 1;
}

.post-row {
  --post-rule-inset: calc((100% + var(--grid-gap)) / 2);

  position: relative;
  min-height: 72px;
  padding-block: var(--space-sm);
  align-items: start;
  color: #000000;
  font-size: var(--font-size-base);
  line-height: 1.375;
}

.post-row__primary,
.post-row__secondary {
  min-width: 0;
}

.post-row__primary {
  display: contents;
}

.post-row__secondary {
  grid-column: 4;
  display: grid;
  grid-template-columns: minmax(0, 1fr) max-content;
  gap: var(--space-3xl);
  padding-right: var(--space-xl);
  align-items: start;
}

@media (min-width: 1361px) {
  .post-row {
    display: grid;
    grid-template-columns: 300px minmax(0, 1fr) max-content;
    column-gap: var(--space-3xl);
    padding-right: var(--space-xl);
    padding-left: calc((100% + var(--grid-gap)) / 2);
  }

  .post-row__primary,
  .post-row__secondary {
    display: contents;
  }

  .post-row > .post-row__primary > .post-row__title {
    grid-column: 1;
  }

  .post-row > .post-row__secondary > .post-row__summary {
    grid-column: 2;
  }

  .post-row > .post-row__secondary > .post-row__link {
    grid-column: 3;
  }
}

.post-row::before {
  position: absolute;
  z-index: 2;
  top: 0;
  right: var(--space-xl);
  left: var(--post-rule-inset);
  border-top: 1px solid var(--color-external-link-bg);
  border-color: color-mix(
    in srgb,
    var(--color-subtle) 20%,
    var(--color-external-link-bg)
  );
  content: "";
  pointer-events: none;
}

.post-row--year-start {
  --post-rule-inset: calc(
    ((100% - var(--grid-gap)) / 2) - var(--post-date-rail-width)
  );
}

.post-row--month-start {
  --post-rule-inset: calc(
    ((100% - var(--grid-gap)) / 2) - var(--post-date-edge-inset) -
      var(--post-month-slot-width)
  );
}

.post-row__year,
.post-row__month {
  position: sticky;
  z-index: 5;
  top: var(--posts-date-sticky-top);
  grid-column: 2;
  grid-row: 1;
  align-self: start;
  justify-self: end;
  background: var(--color-bg);
  background-clip: content-box;
  color: var(--color-caption);
  font: inherit;
  font-variant-numeric: tabular-nums;
  text-align: right;
  transform: translateY(var(--post-date-row-offset));
}

.post-row__year {
  width: calc(
    var(--post-date-rail-width) - var(--post-date-edge-inset) -
      var(--post-month-slot-width) - var(--post-date-pair-gap)
  );
  margin-right: calc(
    var(--post-date-edge-inset) + var(--post-month-slot-width) +
      var(--post-date-pair-gap)
  );
}

.post-row__month {
  z-index: 6;
  width: var(--post-month-slot-width);
  margin-right: var(--post-date-edge-inset);
}

.post-row__compact-date {
  display: none;
}

.post-row__title,
.post-row__summary {
  min-width: 0;
  margin: 0;
  font: inherit;
}

.post-row__title {
  grid-column: 3;
  text-wrap: balance;
}

.post-row__summary {
  color: var(--color-subtle);
  font-size: 14px;
  line-height: var(--line-height-description);
  letter-spacing: var(--tracking-description);
  text-wrap: pretty;
}

.post-row__link {
  position: relative;
  display: inline-flex;
  gap: 0.35em;
  align-items: baseline;
  width: max-content;
  min-width: 0;
  white-space: nowrap;
  text-decoration-line: none;
}

.post-row__link::after {
  position: absolute;
  right: 0;
  bottom: 1px;
  left: 0;
  height: 1px;
  background: currentColor;
  content: "";
  opacity: 0;
  pointer-events: none;
}

.post-row__link.internal-link:focus-visible {
  text-decoration-line: none;
}

.post-row__link:focus-visible::after {
  opacity: 1;
}

@media (any-hover: hover) and (any-pointer: fine) {
  .post-row__link.internal-link:hover {
    text-decoration-line: none;
  }

  .post-row__link:hover::after {
    opacity: 1;
  }
}

.post-row__link-label--compact {
  display: none;
}

.post-row[hidden],
.post-month-group[hidden],
.post-year-group[hidden] {
  display: none;
}

/* Starts in the viewport's bottom-left corner (offset set by posts.js),
   scrolls with the archive, then sticks to the top. Sharing the list's
   grid row gives the sticky element the full archive height to travel. */
.featured-post {
  position: sticky;
  z-index: 4;
  top: max(var(--page-gutter), env(safe-area-inset-top));
  grid-column: 1;
  grid-row: 1;
  align-self: start;
  margin-top: var(--featured-post-offset, 0px);
  display: block;
  width: 200px;
  max-width: calc(100% - 2 * var(--page-gutter));
  background: var(--color-bg);
}

.featured-post__eyebrow {
  display: block;
  margin-bottom: var(--space-lg);
  color: var(--color-caption);
  font-size: var(--font-size-base);
  line-height: var(--line-height-compact);
}

.featured-article__media--math {
  display: grid;
  place-items: center;
  background: var(--color-media-bg);
}

.featured-article__image--math {
  object-position: center;
}

@media (min-width: 1101px) and (max-width: 1360px) {
  .post-row__secondary {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--space-lg);
  }
}

@media (max-width: 1100px) {
  .post-year-group__months,
  .post-month-group__posts {
    gap: 0;
  }

  .post-list {
    --post-date-rail-width: 90px;
    --post-date-edge-inset: 0px;
    --post-date-pair-gap: 4px;
    --post-date-row-offset: var(--space-lg);
  }

  .post-row__year,
  .post-row__month {
    grid-column: 1;
    justify-self: start;
  }

  .post-row__year {
    width: calc(
      var(--post-date-rail-width) - var(--post-month-slot-width) -
        var(--post-date-pair-gap)
    );
    margin-right: 0;
  }

  .post-row__month {
    width: var(--post-month-slot-width);
    margin-right: 0;
    margin-left: calc(
      var(--post-date-rail-width) - var(--post-month-slot-width)
    );
  }

  .post-row {
    grid-template-columns: var(--page-grid-columns);
    min-height: 0;
    padding-block: var(--space-lg);
  }

  .post-row--year-start {
    --post-rule-inset: 0;
  }

  .post-row--month-start {
    --post-rule-inset: calc(
      var(--post-date-rail-width) - var(--post-month-slot-width) -
        var(--post-date-edge-inset)
    );
  }

  .post-row__primary,
  .post-row__secondary {
    display: grid;
    min-width: 0;
    align-content: start;
  }

  .post-row__primary {
    grid-column: 1;
    grid-template-columns: var(--post-date-rail-width) minmax(0, 1fr);
    column-gap: var(--space-xl);
    row-gap: 0;
    padding-right: var(--space-xl);
  }

  .post-row__secondary {
    grid-column: 2;
    grid-template-columns: minmax(0, 1fr) max-content;
    gap: var(--space-xl);
  }

  .post-row__title {
    grid-column: 2;
    padding-right: 0;
  }

  .post-row--month-continuation {
    --post-rule-inset: calc(
      var(--post-date-rail-width) + var(--space-xl)
    );
  }
}

@media (max-width: 900px) {
  .post-row__secondary {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--space-md);
  }
}

@media (max-width: 760px) {
  .posts-page {
    --posts-date-sticky-top: var(--mobile-header-height);
  }

  .post-row__year,
  .post-row__month {
    transition: top var(--mobile-header-motion-duration)
      var(--mobile-header-motion-easing);
  }

  /* Target the rails directly so hiding the header doesn't restyle the page. */
  .site-header.is-mobile-hidden ~ main :is(.post-row__year, .post-row__month) {
    top: 0;
    transition-duration: 300ms;
    transition-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
  }

  .post-row {
    grid-template-columns: var(--post-date-rail-width) minmax(0, 1fr);
    column-gap: var(--space-xl);
  }

  .post-row__primary,
  .post-row__secondary {
    grid-column: 2;
    padding-right: 0;
  }

  .post-row__primary {
    grid-template-columns: minmax(0, 1fr);
    row-gap: var(--space-xs);
  }

  .post-row--year-start .post-row__primary,
  .post-row--month-start .post-row__primary {
    padding-top: 0;
  }

  .post-row__title {
    grid-column: 1;
  }

  .post-row__secondary {
    margin-top: var(--space-md);
  }

  .post-row--month-start {
    --post-rule-inset: calc(
      var(--post-date-rail-width) - var(--post-month-slot-width)
    );
  }

  .post-row--month-continuation {
    --post-rule-inset: calc(
      var(--post-date-rail-width) + var(--space-xl)
    );
  }

  .post-row--month-continuation::before {
    right: 0;
  }
}

@media (max-width: 450px) {
  /* Stack the month under the year so the rail only needs to fit "2026". */
  .post-list {
    --post-date-rail-width: 44px;
    --post-month-slot-width: 44px;
  }

  .post-row__year {
    width: var(--post-date-rail-width);
    overflow: hidden;
    text-align: left;
    white-space: nowrap;
  }

  /* Slides under the pinned year when its month group scrolls away. */
  .post-row__month {
    z-index: 4;
    top: calc(var(--posts-date-sticky-top) + 1lh);
    margin-left: 0;
    text-align: left;
  }

  .post-month-group__layout:has(.post-row--year-start) > .post-row__month {
    margin-top: 1lh;
  }

  .site-header.is-mobile-hidden ~ main .post-row__month {
    top: 1lh;
  }
}

/* Keep the desktop feature compact on short viewports. */
@media (min-width: 1101px) and (max-height: 600px) {
  .featured-post__eyebrow {
    margin-bottom: var(--space-sm);
  }

  .featured-post .featured-article__media {
    display: none;
  }

  .featured-post .featured-article__title {
    margin-bottom: 0;
  }

  .featured-post .featured-article__cta {
    margin-top: var(--space-sm);
  }
}

/* The archive uses the feature's column below this breakpoint. */
@media (max-width: 1100px) {
  .featured-post {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .posts-page.has-post-reveal-motion .posts-intro > *,
  .posts-page.has-post-reveal-motion .post-row {
    opacity: 1;
    transform: none;
    transition: none;
  }
}