/* Topic top nav + section sidebar/chips + landing + archive
   Mobile-first (360–430px), desktop sidebar from 1024px. */

:root {
  --header-offset: 3.25rem;
  --page-pad: max(1rem, env(safe-area-inset-left, 0px));
  --page-pad-right: max(1rem, env(safe-area-inset-right, 0px));
  --tap-min: 44px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* —— Sticky top bar (hides on scroll down) —— */

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  margin: 0;
  padding: 0;
  padding-top: env(safe-area-inset-top, 0px);
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg) 94%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  transform: translateY(0);
  transition: transform 0.22s ease;
  will-change: transform;
}

.site-header--hidden {
  transform: translateY(-100%);
}

.site-header__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem 0.75rem;
  max-width: 72rem;
  margin: 0 auto;
  padding: 0.45rem var(--page-pad) 0.45rem var(--page-pad-right);
  min-height: var(--tap-min);
}

.site-brand {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  min-width: 0;
  text-decoration: none;
  color: var(--text);
  flex-shrink: 1;
}

.site-brand__lockup {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  min-width: 0;
}

.site-brand__mark {
  position: relative;
  width: 1.75rem;
  height: 1.75rem;
  flex-shrink: 0;
  border-radius: 0.4rem;
  overflow: hidden;
}

.site-brand__mark img {
  display: block;
  width: 100%;
  height: 100%;
}

.site-brand__mark-paper {
  display: none;
}

@media (prefers-color-scheme: dark) {
  .site-brand__mark-ink {
    display: none;
  }

  .site-brand__mark-paper {
    display: block;
  }
}

.site-brand .site-title,
.site-brand__word {
  margin: 0;
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--text);
  white-space: nowrap;
}

.site-brand__l {
  color: var(--accent);
}

.site-brand:hover .site-title,
.site-brand:hover .site-brand__word {
  color: var(--text);
}

.site-brand:hover .site-brand__l {
  color: var(--link-hover);
}

.site-brand .site-tagline,
.site-brand__motto {
  display: none;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.62rem;
  font-weight: 400;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-muted);
  line-height: 1.3;
  max-width: 22rem;
}

.top-nav {
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  gap: 0.2rem;
  font-family: var(--font-sans);
  flex-shrink: 0;
}

.top-nav__link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: var(--tap-min);
  min-width: var(--tap-min);
  padding: 0 0.55rem;
  border: 1px solid transparent;
  border-radius: 2px;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.8rem;
  font-weight: 600;
  line-height: 1.2;
  -webkit-tap-highlight-color: transparent;
}

.top-nav__link:hover {
  color: var(--accent);
}

.top-nav__link--active {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-soft);
}

/* —— Shell —— */

.site-shell {
  width: 100%;
  max-width: 72rem;
  margin: 0 auto;
  padding: 0 var(--page-pad) 0 var(--page-pad-right);
  overflow-x: clip;
}

.site-shell--with-nav {
  display: flex;
  flex-direction: column;
  gap: 0;
  padding-top: 0;
  padding-bottom: calc(1.5rem + env(safe-area-inset-bottom, 0px));
}

.site-shell--with-nav .site-main {
  max-width: var(--max-width);
  width: 100%;
  margin: 0;
  padding: 0.85rem 0 2rem;
  min-width: 0;
}

body:not(.has-section-nav) .site-main {
  max-width: var(--max-width);
  margin-inline: auto;
  padding: 1.25rem 0 calc(2rem + env(safe-area-inset-bottom, 0px));
}

/* —— Section chips (mobile sticky under header) —— */

.section-nav {
  position: sticky;
  top: var(--header-offset);
  z-index: 15;
  margin: 0 calc(-1 * var(--page-pad)) 0 calc(-1 * var(--page-pad-right));
  padding: 0.4rem var(--page-pad) 0.45rem var(--page-pad-right);
  background: color-mix(in srgb, var(--bg) 96%, transparent);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  font-family: var(--font-sans);
  transition: top 0.22s ease;
}

.site-header--hidden ~ .site-shell .section-nav {
  top: 0;
}

.section-nav__label {
  display: none;
}

.section-nav__list {
  display: flex;
  flex-direction: row;
  flex-wrap: nowrap;
  gap: 0.35rem;
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
  overscroll-behavior-x: contain;
  scroll-snap-type: x proximity;
  padding: 0.1rem 0;
  margin: 0;
}

.section-nav__list::-webkit-scrollbar {
  display: none;
}

.section-nav__item {
  appearance: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  min-height: var(--tap-min);
  padding: 0 0.85rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg-elevated);
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  line-height: 1.2;
  white-space: nowrap;
  cursor: pointer;
  scroll-snap-align: start;
  -webkit-tap-highlight-color: transparent;
}

.section-nav__item:hover {
  color: var(--accent);
  border-color: var(--accent);
}

.section-nav__item--active {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-soft);
  font-weight: 700;
}

.topic-section {
  scroll-margin-top: calc(var(--header-offset) + 3.25rem);
  margin-bottom: 1.5rem;
}

.topic-section__title {
  margin: 0 0 0.75rem;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 600;
}

.has-section-nav .ai-chips {
  display: none !important;
}

/* —— Landing —— */

.landing {
  padding: 1.5rem 0 2.5rem;
}

.landing__title {
  margin: 0;
  font-family: var(--font-serif);
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.landing__hero {
  margin: 0;
  font-family: var(--font-serif);
  font-style: italic;
  font-weight: 400;
  font-size: clamp(1.85rem, 5.5vw, 2.75rem);
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--text);
  max-width: 18ch;
}

.landing__subline {
  margin: 0.65rem 0 1.6rem;
  color: var(--text-muted);
  font-family: var(--font-serif);
  font-size: 1.05rem;
  line-height: 1.45;
  max-width: 28rem;
}

.landing__eyebrow {
  margin: 0 0 0.35rem;
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
  color: var(--text);
}

.landing__meta {
  margin: 0 0 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.landing__tagline {
  margin: 0.45rem 0 1.35rem;
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  line-height: 1.5;
  max-width: 28rem;
}

.landing__cards {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
}

.landing-card {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  min-height: var(--tap-min);
  padding: 1rem 1.05rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--bg-elevated);
  text-decoration: none;
  color: var(--text);
  font-family: var(--font-sans);
  transition: border-color 0.15s ease, background 0.15s ease;
}

.landing-card:hover {
  border-color: var(--accent);
  background: var(--accent-soft);
  color: var(--text);
}

.landing-card__topic {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
}

.landing-card__title {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 600;
  line-height: 1.35;
}

.landing-card__date {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.landing-card__cta {
  margin-top: 0.4rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent);
}

.landing__archive {
  margin: 1.35rem 0 0;
  font-family: var(--font-sans);
  font-size: 0.9rem;
}

.landing__archive a {
  display: inline-flex;
  align-items: center;
  min-height: var(--tap-min);
}

/* —— Archive —— */

.archive-page {
  padding: 1.25rem 0 calc(2rem + env(safe-area-inset-bottom, 0px));
  max-width: 40rem;
}

.archive-page__title {
  margin: 0;
  font-family: var(--font-serif);
  font-size: 1.65rem;
  line-height: 1.2;
}

.archive-page__lead {
  margin: 0.35rem 0 1.1rem;
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  line-height: 1.5;
}

.archive-page__controls {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  margin-bottom: 0.85rem;
}

.archive-search__input {
  width: 100%;
  box-sizing: border-box;
  min-height: var(--tap-min);
  padding: 0.65rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--bg-elevated);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 1rem; /* avoid iOS zoom */
}

.archive-search__input:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.archive-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.archive-filter {
  appearance: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: var(--tap-min);
  padding: 0 0.85rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg-elevated);
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.archive-filter--active,
.archive-filter:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-soft);
}

.archive-page__status {
  font-family: var(--font-sans);
  font-size: 0.8rem;
  color: var(--text-muted);
  margin: 0 0 0.65rem;
}

.archive-month {
  border-top: 1px solid var(--border);
  padding: 0.2rem 0;
}

.archive-month__summary {
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  min-height: var(--tap-min);
  display: flex;
  align-items: center;
  padding: 0.35rem 0;
  color: var(--text);
  list-style: none;
}

.archive-month__summary::-webkit-details-marker {
  display: none;
}

.archive-month__summary::before {
  content: "▸ ";
  color: var(--text-muted);
  font-size: 0.75rem;
  margin-right: 0.25rem;
}

.archive-month[open] > .archive-month__summary::before {
  content: "▾ ";
}

.archive-month__list {
  list-style: none;
  margin: 0 0 0.5rem;
  padding: 0;
}

.archive-month__item {
  display: grid;
  grid-template-columns: 3.5rem 1fr;
  gap: 0.25rem 0.65rem;
  align-items: baseline;
  padding: 0.65rem 0;
  border-top: 1px solid var(--border);
  font-family: var(--font-sans);
  font-size: 0.92rem;
}

.archive-month__item time {
  color: var(--text-muted);
  font-size: 0.78rem;
  font-variant-numeric: tabular-nums;
}

.archive-month__item a {
  color: var(--text);
  text-decoration: none;
  display: inline-block;
  padding: 0.15rem 0;
  overflow-wrap: anywhere;
}

.archive-month__item a:hover {
  color: var(--accent);
  text-decoration: underline;
}

.archive-month__item .badge {
  grid-column: 2;
  justify-self: start;
}

.site-footer__inner {
  max-width: 72rem;
  padding-left: max(1rem, env(safe-area-inset-left, 0px));
  padding-right: max(1rem, env(safe-area-inset-right, 0px));
  padding-bottom: env(safe-area-inset-bottom, 0px);
}

/* —— Tablet+ —— */

@media (min-width: 640px) {
  .landing__cards {
    grid-template-columns: 1fr 1fr;
  }

  .archive-month__item {
    grid-template-columns: 4rem 1fr auto;
  }

  .archive-month__item .badge {
    grid-column: auto;
    justify-self: end;
  }
}

/* —— Desktop: left sidebar from 1024px —— */

@media (min-width: 1024px) {
  :root {
    --page-pad: 1.25rem;
    --page-pad-right: 1.25rem;
  }

  .site-header__bar {
    align-items: center;
    padding: 0.85rem 1.25rem 0.75rem;
  }

  .site-brand .site-title,
  .site-brand__word {
    font-size: 1.2rem;
  }

  .site-brand__mark {
    width: 2rem;
    height: 2rem;
  }

  /* Subtle motto under brand on desktop only */
  .site-brand__motto {
    display: block;
    padding-left: calc(2rem + 0.5rem);
  }

  .top-nav {
    gap: 0.35rem;
  }

  .top-nav__link {
    min-width: 0;
    padding: 0.4rem 0.7rem;
  }

  .site-shell--with-nav {
    display: grid;
    grid-template-columns: 13.5rem minmax(0, 1fr);
    gap: 1.5rem 2rem;
    align-items: start;
    padding-top: 1.25rem;
    padding-bottom: 2rem;
  }

  .section-nav {
    position: sticky;
    top: calc(var(--header-offset) + 0.75rem);
    z-index: 5;
    margin: 0;
    padding: 0.25rem 0 1rem;
    background: transparent;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    border-bottom: none;
  }

  .section-nav__label {
    display: block;
    margin: 0 0 0.5rem;
    font-size: 0.65rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-muted);
  }

  .section-nav__list {
    flex-direction: column;
    overflow: visible;
    scroll-snap-type: none;
    gap: 0.2rem;
  }

  .section-nav__item {
    width: 100%;
    justify-content: flex-start;
    border-radius: 2px;
    border-color: transparent;
    background: transparent;
    min-height: 2.25rem;
    padding: 0.4rem 0.55rem;
    white-space: normal;
    font-size: 0.8rem;
  }

  .section-nav__item--active {
    border-color: var(--border);
    background: var(--bg-elevated);
  }

  .topic-section {
    scroll-margin-top: calc(var(--header-offset) + 1rem);
  }
}