/* ====================================================================
   Framework Taxonomy — Swiss-modernist editorial design
   Palette: warm off-white, navy, coral
   Type: Instrument Serif (headings), Source Sans 3 (body)
   ==================================================================== */

:root {
  /* Palette */
  --bg:           #F4EFE6;   /* warm off-white */
  --bg-alt:       #ECE5D6;   /* deeper paper */
  --surface:      #FBF7EE;   /* card */
  --ink:          #16223D;   /* navy */
  --ink-soft:     #2A3656;   /* navy muted */
  --ink-faint:    #6B7494;   /* navy faint */
  --rule:         #C9BFAA;   /* warm border */
  --rule-soft:    #DDD3BD;
  --coral:        #E85D45;   /* coral accent */
  --coral-deep:   #C8482F;
  --coral-tint:   #F5C9BD;

  /* Type */
  --serif: "Instrument Serif", "Source Serif 4", "Iowan Old Style", Georgia, serif;
  --sans:  "Source Sans 3", "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono:  "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  /* Scale (modular, editorial) */
  --t-hero:    clamp(3.5rem, 9vw, 8.5rem);
  --t-display: clamp(2.5rem, 5.5vw, 4.75rem);
  --t-h2:      clamp(2rem, 3.5vw, 3.25rem);
  --t-h3:      clamp(1.35rem, 1.8vw, 1.6rem);
  --t-lead:    clamp(1.125rem, 1.2vw, 1.3rem);
  --t-body:    1.0625rem;
  --t-sm:      0.875rem;
  --t-xs:      0.75rem;

  /* Layout */
  --max:       1240px;
  --gutter:    clamp(1.25rem, 3vw, 2.5rem);
  --col-gap:   clamp(1rem, 2vw, 2rem);

  /* Motion */
  --ease:      cubic-bezier(0.22, 1, 0.36, 1);
  --dur:       640ms;
}

/* Reset */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: var(--t-body);
  line-height: 1.6;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}
img, svg { display: block; max-width: 100%; }

/* Selection */
::selection { background: var(--coral); color: var(--bg); }

/* Links */
a { color: var(--ink); text-decoration: none; transition: color 200ms var(--ease); }
a:hover { color: var(--coral); }
a:focus-visible {
  outline: 2px solid var(--coral);
  outline-offset: 3px;
  border-radius: 2px;
}

/* Skip link */
.skip-link {
  position: absolute; left: 0; top: 0;
  padding: 0.75rem 1rem;
  background: var(--ink);
  color: var(--bg);
  transform: translateY(-200%);
  transition: transform 200ms;
  z-index: 1000;
}
.skip-link:focus { transform: translateY(0); }

/* =============================================================== */
/* Reading progress bar                                            */
/* =============================================================== */
.progress {
  position: fixed; top: 0; left: 0;
  height: 3px; width: 0%;
  background: var(--coral);
  z-index: 200;
  transition: width 100ms linear;
}

/* =============================================================== */
/* Header / nav                                                    */
/* =============================================================== */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(244, 239, 230, 0.92);
  backdrop-filter: saturate(150%) blur(12px);
  -webkit-backdrop-filter: saturate(150%) blur(12px);
  border-bottom: 1px solid var(--rule-soft);
}
.site-header__inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0.9rem var(--gutter);
  display: flex; align-items: center; justify-content: space-between;
  gap: 1.5rem;
}
.brand {
  display: flex; align-items: center; gap: 0.7rem;
  font-family: var(--serif);
  font-size: 1.25rem;
  letter-spacing: 0.01em;
  line-height: 1;
}
.brand svg { width: 28px; height: 28px; flex: none; }
.brand-name { font-weight: 400; white-space: nowrap; }
@media (max-width: 520px) {
  .brand-name { font-size: 1.05rem; }
}
@media (max-width: 380px) {
  .brand-name .brand-the { display: none; }
}
.brand-name em { font-style: italic; color: var(--coral); }

.site-nav { display: flex; gap: 1.5rem; align-items: center; font-size: var(--t-sm); }
.site-nav a {
  color: var(--ink-soft);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-weight: 500;
}
.site-nav a:hover { color: var(--coral); }
@media (max-width: 720px) { .site-nav .nav-meta { display: none; } }

/* =============================================================== */
/* Layout grid                                                     */
/* =============================================================== */
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 var(--gutter); }

/* =============================================================== */
/* Hero                                                            */
/* =============================================================== */
.hero {
  padding: clamp(3rem, 9vw, 8rem) 0 clamp(3rem, 7vw, 6rem);
  border-bottom: 1px solid var(--rule);
  position: relative;
  overflow: hidden;
}
.hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(1.5rem, 4vw, 3rem);
  align-items: end;
}
@media (min-width: 900px) {
  .hero__grid { grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr); }
}
.hero__eyebrow {
  font-family: var(--sans);
  font-size: var(--t-xs);
  text-transform: uppercase;
  letter-spacing: 0.32em;
  color: var(--ink-faint);
  margin: 0 0 1.25rem;
  display: flex; align-items: center; gap: 0.85rem;
}
.hero__eyebrow::before {
  content: ""; display: inline-block;
  width: 36px; height: 1px;
  background: var(--coral);
}
.hero__title {
  font-family: var(--serif);
  font-weight: 400;
  font-size: var(--t-hero);
  line-height: 0.94;
  letter-spacing: -0.02em;
  margin: 0;
  color: var(--ink);
}
.hero__title em { font-style: italic; color: var(--coral); }
.hero__lede {
  font-size: var(--t-lead);
  line-height: 1.5;
  color: var(--ink-soft);
  max-width: 44ch;
  margin: 0;
}
.hero__meta {
  margin-top: 2.5rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
}
.hero__meta dt {
  font-size: var(--t-xs);
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--ink-faint);
  margin-bottom: 0.35rem;
}
.hero__meta dd {
  margin: 0;
  font-family: var(--serif);
  font-size: 1.6rem;
  line-height: 1.1;
  color: var(--ink);
}
.hero__meta dd em { color: var(--coral); font-style: italic; }
.hero__meta a { border-bottom: 1px solid var(--rule); }
.hero__meta a:hover { border-bottom-color: var(--coral); color: var(--coral); }

/* =============================================================== */
/* Intro + TOC                                                     */
/* =============================================================== */
.intro {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(2rem, 5vw, 5rem);
  padding-top: clamp(3rem, 6vw, 5rem);
  padding-bottom: clamp(3rem, 6vw, 5rem);
}
@media (min-width: 900px) {
  .intro { grid-template-columns: minmax(0, 0.75fr) minmax(0, 1.25fr); }
}

.intro__note p {
  font-family: var(--serif);
  font-size: clamp(1.25rem, 1.5vw, 1.55rem);
  line-height: 1.45;
  color: var(--ink-soft);
  margin: 0 0 1rem;
  max-width: 38ch;
}
.intro__note p:first-child { color: var(--ink); }

.toc {
  font-family: var(--sans);
}
.toc__title {
  font-family: var(--sans);
  font-size: var(--t-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.28em;
  color: var(--ink-faint);
  margin: 0 0 1.5rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--rule);
}
.toc__list {
  list-style: none;
  margin: 0; padding: 0;
  columns: 2;
  column-gap: 2rem;
}
@media (min-width: 1080px) { .toc__list { columns: 2; } }
@media (max-width: 540px) { .toc__list { columns: 1; } }
.toc__item {
  break-inside: avoid;
  padding: 0.45rem 0;
  border-bottom: 1px dotted var(--rule-soft);
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
}
.toc__item a {
  flex: 1;
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  font-size: 0.95rem;
  color: var(--ink-soft);
}
.toc__item a:hover { color: var(--coral); }
.toc__num {
  font-variant-numeric: tabular-nums;
  font-size: var(--t-xs);
  color: var(--ink-faint);
  letter-spacing: 0.06em;
  min-width: 1.6rem;
}
.toc__name { flex: 1; }
.toc__count {
  font-variant-numeric: tabular-nums;
  font-size: var(--t-xs);
  color: var(--ink-faint);
}
.toc__item.is-muted a {
  color: var(--ink-faint);
  opacity: 0.45;
}

/* =============================================================== */
/* Search + filtering                                               */
/* =============================================================== */
.filter-panel {
  border-bottom: 1px solid var(--rule);
  background:
    linear-gradient(90deg, rgba(232, 93, 69, 0.08), transparent 42%),
    var(--surface);
}
.filter-panel__inner {
  padding-top: clamp(2rem, 4vw, 3.5rem);
  padding-bottom: clamp(2rem, 4vw, 3.5rem);
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}
@media (min-width: 980px) {
  .filter-panel__inner {
    grid-template-columns: minmax(220px, 0.58fr) minmax(0, 1.42fr);
    align-items: end;
  }
}
.filter-panel__eyebrow {
  margin: 0 0 0.6rem;
  font-size: var(--t-xs);
  font-weight: 600;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.filter-panel h2 {
  margin: 0;
  max-width: 12ch;
  font-family: var(--serif);
  font-size: clamp(1.75rem, 3vw, 3rem);
  font-weight: 400;
  line-height: 1;
  color: var(--ink);
}
.filter-form {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.9rem;
}
@media (min-width: 720px) {
  .filter-form {
    grid-template-columns: minmax(260px, 1fr) minmax(220px, 0.42fr) auto;
    align-items: end;
  }
}
.filter-field {
  display: grid;
  gap: 0.45rem;
}
.filter-field span {
  font-size: var(--t-xs);
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.filter-field input,
.filter-field select {
  width: 100%;
  min-height: 48px;
  border: 1px solid var(--rule);
  border-radius: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1rem;
  line-height: 1.2;
  padding: 0.75rem 0.9rem;
  box-shadow: none;
  transition: border-color 180ms var(--ease), background-color 180ms var(--ease);
}
.filter-field input:focus,
.filter-field select:focus {
  outline: 2px solid var(--coral);
  outline-offset: 2px;
  border-color: var(--coral);
  background: #fffaf1;
}
.filter-field input::placeholder { color: var(--ink-faint); opacity: 0.75; }
.filter-clear {
  min-height: 48px;
  border: 1px solid var(--ink);
  background: var(--ink);
  color: var(--bg);
  font-family: var(--sans);
  font-size: var(--t-xs);
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  padding: 0.75rem 1rem;
  cursor: pointer;
  transition: background 180ms var(--ease), border-color 180ms var(--ease), color 180ms var(--ease);
}
.filter-clear:hover,
.filter-clear:focus-visible {
  background: var(--coral);
  border-color: var(--coral);
  color: var(--bg);
}
.filter-status,
.filter-empty {
  margin: 0;
  grid-column: 1 / -1;
  font-size: var(--t-sm);
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
}
.filter-empty {
  color: var(--coral-deep);
}
.section.is-filter-hidden,
.frameworks li.is-filter-hidden {
  display: none;
}
mark.fw-hit {
  background: linear-gradient(180deg, transparent 48%, var(--coral-tint) 48%);
  color: inherit;
  padding: 0 0.02em;
}

/* =============================================================== */
/* Sticky TOC drawer (desktop)                                     */
/* =============================================================== */
.toc-rail {
  position: fixed;
  top: 50%; right: 1.25rem;
  transform: translateY(-50%);
  z-index: 90;
  display: none;
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 0.9rem 0.75rem;
  width: 220px;
  max-height: 68vh;
  overflow-y: auto;
  box-shadow: 0 24px 60px -28px rgba(22, 34, 61, 0.25);
  font-size: 0.74rem;
}
.toc-rail::-webkit-scrollbar { width: 4px; }
.toc-rail::-webkit-scrollbar-thumb { background: var(--rule); border-radius: 2px; }
/* Only show when there's room to the right of content (max + rail-width + gutter) */
/* Show rail when viewport >= content + rail + gutters */
@media (min-width: 1480px) { .toc-rail { display: block; } }
.toc-rail__title {
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.22em;
  color: var(--ink-faint);
  margin: 0 0 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--rule-soft);
}
.toc-rail__list { list-style: none; margin: 0; padding: 0; }
.toc-rail__list li { margin: 0; }
.toc-rail__list a {
  display: flex;
  gap: 0.5rem;
  padding: 0.3rem 0.4rem;
  border-radius: 3px;
  color: var(--ink-soft);
  line-height: 1.3;
  transition: all 180ms var(--ease);
}
.toc-rail__list a:hover { background: var(--bg-alt); color: var(--ink); }
.toc-rail__list a.is-active {
  background: var(--ink);
  color: var(--bg);
}
.toc-rail__list a.is-muted {
  opacity: 0.42;
}
.toc-rail__list a.is-active .toc-rail__num { color: var(--coral-tint); }
.toc-rail__num {
  font-variant-numeric: tabular-nums;
  color: var(--ink-faint);
  min-width: 1.4rem;
}

/* =============================================================== */
/* Section                                                         */
/* =============================================================== */
.section {
  padding: clamp(3.5rem, 7vw, 6rem) 0;
  border-bottom: 1px solid var(--rule);
  scroll-margin-top: 90px;
}
.section:nth-child(even) { background: var(--bg-alt); }

.section__head {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(1.5rem, 4vw, 3rem);
  margin-bottom: clamp(2rem, 4vw, 3.5rem);
  align-items: start;
}
@media (min-width: 900px) {
  .section__head { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
}

.section__label {
  display: flex; align-items: center; gap: 1rem;
  font-size: var(--t-xs);
  text-transform: uppercase;
  letter-spacing: 0.3em;
  color: var(--ink-faint);
  margin: 0 0 1.25rem;
  font-weight: 500;
}
.section__label::before {
  content: "";
  width: 28px; height: 1px;
  background: var(--coral);
}
.section__number {
  font-family: var(--serif);
  font-style: italic;
  font-size: 1rem;
  color: var(--coral);
  letter-spacing: 0;
  text-transform: none;
}
.section__title {
  font-family: var(--serif);
  font-weight: 400;
  font-size: var(--t-display);
  line-height: 0.98;
  letter-spacing: -0.015em;
  margin: 0;
  color: var(--ink);
}
.section__art {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 220px;
}
.section__art svg {
  width: 100%;
  max-width: 360px;
  height: auto;
}
.section__meta {
  display: flex;
  gap: 2rem;
  margin-top: 1.5rem;
  font-size: var(--t-sm);
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
}
.section__meta strong {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 400;
  color: var(--coral);
  font-size: 1.25rem;
}

/* Framework grid */
.frameworks {
  list-style: none;
  margin: 0; padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 0;
  border-top: 1px solid var(--rule);
}
.frameworks li {
  position: relative;
  padding: 0.85rem 1rem 0.95rem 0;
  border-bottom: 1px solid var(--rule-soft);
  font-size: 0.98rem;
  line-height: 1.4;
  color: var(--ink-soft);
  display: grid;
  grid-template-columns: 2.55rem minmax(0, 1fr);
  align-items: start;
  gap: 0.65rem;
  transition: color 220ms var(--ease), background-color 220ms var(--ease);
}
.frameworks li:hover {
  color: var(--ink);
  background: linear-gradient(90deg, rgba(232, 93, 69, 0.035), transparent 58%);
}
.frameworks li::before {
  content: counter(fw, decimal-leading-zero);
  counter-increment: fw;
  grid-column: 1;
  grid-row: 1 / span 2;
  font-variant-numeric: tabular-nums;
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--ink-faint);
  flex: none;
  letter-spacing: 0.03em;
  padding-top: 0.15rem;
}
.frameworks { counter-reset: fw; }
.framework-toggle {
  grid-column: 2;
  appearance: none;
  border: 0;
  padding: 0;
  margin: 0;
  background: transparent;
  color: inherit;
  font: inherit;
  text-align: left;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 0.75rem;
  align-items: baseline;
  cursor: pointer;
}
.framework-toggle:focus-visible {
  outline: 2px solid var(--coral);
  outline-offset: 4px;
}
.fw-name { min-width: 0; }
.fw-qual {
  color: var(--ink-faint);
  font-size: 0.86rem;
  font-style: italic;
}
.fw-cue {
  font-size: 0.62rem;
  font-family: var(--mono);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-faint);
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity 180ms var(--ease), transform 180ms var(--ease), color 180ms var(--ease);
}
.frameworks li:hover .fw-cue,
.framework-toggle:focus-visible .fw-cue,
.framework-toggle[aria-expanded="true"] .fw-cue {
  opacity: 1;
  transform: translateX(0);
}
.framework-toggle[aria-expanded="true"] .fw-cue {
  color: var(--coral);
}
.framework-toggle[aria-expanded="true"] .fw-cue::before {
  content: "Collapse";
}
.framework-toggle[aria-expanded="true"] .fw-cue {
  font-size: 0;
}
.framework-toggle[aria-expanded="true"] .fw-cue::before {
  font-size: 0.62rem;
}
.fw-desc {
  grid-column: 2;
  margin: 0.55rem 0 0;
  max-width: 62ch;
  padding-left: 0.8rem;
  border-left: 2px solid var(--coral);
  color: var(--ink-faint);
  font-size: 0.92rem;
  line-height: 1.45;
}
.fw-desc:not([hidden]) {
  animation: descIn 180ms var(--ease) both;
}
@keyframes descIn {
  from { opacity: 0; transform: translateY(-3px); }
  to { opacity: 1; transform: translateY(0); }
}

/* =============================================================== */
/* Reveal animations                                               */
/* =============================================================== */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}
.reveal--delay-1 { transition-delay: 80ms; }
.reveal--delay-2 { transition-delay: 160ms; }

/* =============================================================== */
/* Footer                                                          */
/* =============================================================== */
.site-footer {
  padding: clamp(3rem, 6vw, 5rem) 0 2rem;
  background: var(--ink);
  color: var(--bg);
}
.site-footer .wrap {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}
@media (min-width: 720px) {
  .site-footer .wrap { grid-template-columns: 1.5fr 1fr 1fr; }
}
.site-footer h2 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(1.75rem, 2.5vw, 2.5rem);
  line-height: 1.05;
  margin: 0 0 1rem;
  color: var(--bg);
}
.site-footer h2 em { color: var(--coral); font-style: italic; }
.site-footer p {
  color: rgba(244, 239, 230, 0.7);
  font-size: 0.95rem;
  margin: 0 0 0.75rem;
  max-width: 42ch;
}
.site-footer a {
  color: var(--bg);
  border-bottom: 1px solid rgba(244, 239, 230, 0.3);
}
.site-footer a:hover {
  color: var(--coral);
  border-bottom-color: var(--coral);
}
.footer__col h3 {
  font-family: var(--sans);
  font-size: var(--t-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.24em;
  color: rgba(244, 239, 230, 0.6);
  margin: 0 0 0.85rem;
}
.footer__col ul { list-style: none; margin: 0; padding: 0; }
.footer__col li { padding: 0.25rem 0; font-size: 0.95rem; }
.footer__bottom {
  max-width: var(--max);
  margin: 3rem auto 0;
  padding: 1.5rem var(--gutter) 0;
  border-top: 1px solid rgba(244, 239, 230, 0.15);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.82rem;
  color: rgba(244, 239, 230, 0.5);
  letter-spacing: 0.05em;
}

/* =============================================================== */
/* Section illustration accents (color via currentColor)            */
/* =============================================================== */
.section__art svg .stroke-ink   { stroke: var(--ink); }
.section__art svg .stroke-coral { stroke: var(--coral); }
.section__art svg .fill-coral   { fill: var(--coral); }
.section__art svg .fill-ink     { fill: var(--ink); }
.section__art svg .fill-bg      { fill: var(--bg); }
.section__art svg .stroke-soft  { stroke: var(--ink-soft); opacity: 0.6; }

/* =============================================================== */
/* Print                                                           */
/* =============================================================== */
@media print {
  .progress, .toc-rail, .site-header { display: none; }
  body { background: white; color: black; }
}