:root {
  color-scheme: light;
  --page: #f8f7f2;
  --paper: #fff;
  --ink: #191918;
  --muted: #6d6d68;
  --faint: #979790;
  --line: #deddd6;
  --soft-line: #ebeae4;
  --accent: #315f72;
  --accent-dark: #214754;
  --accent-soft: #e9f0f2;
  --warm: #9a633d;
  --warm-soft: #f4ece5;
  --code: #17222a;
  --serif: Georgia, "Times New Roman", serif;
  --sans:
    Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  font-family: var(--sans);
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  scroll-behavior: smooth;
  scroll-padding-top: 6rem;
  background: var(--page);
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--ink);
  background: var(--page);
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
}

.reading-progress {
  position: fixed;
  z-index: 20;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: transparent;
}

.reading-progress span {
  display: block;
  width: 0;
  height: 100%;
  background: var(--accent);
  transition: width 80ms linear;
}

.site-header {
  position: relative;
  z-index: 10;
  border-bottom: 1px solid var(--soft-line);
  background: rgba(248, 247, 242, 0.82);
  backdrop-filter: blur(22px) saturate(145%);
  -webkit-backdrop-filter: blur(22px) saturate(145%);
}

.site-header__inner {
  display: flex;
  width: min(1120px, calc(100% - 3rem));
  min-height: 4.5rem;
  align-items: center;
  justify-content: space-between;
  margin: 0 auto;
}

.monogram {
  display: grid;
  width: 2rem;
  height: 2rem;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 50%;
  color: var(--ink);
  font-family: var(--serif);
  font-size: 0.7rem;
  font-weight: 700;
  text-decoration: none;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.8rem;
}

.site-nav a {
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 600;
  text-decoration: none;
}

.site-nav a:hover,
.site-nav a:focus-visible,
.site-nav a[aria-current="page"] {
  color: var(--ink);
}

.site-nav__chat {
  padding: 0.65rem 0.9rem;
  border: 1px solid rgba(255, 255, 255, 0.72);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.5);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.85),
    0 8px 24px rgba(35, 49, 54, 0.08);
  backdrop-filter: blur(16px) saturate(145%);
  -webkit-backdrop-filter: blur(16px) saturate(145%);
}

.page-shell {
  display: grid;
  width: min(1120px, calc(100% - 3rem));
  grid-template-columns: minmax(0, 760px) 210px;
  gap: clamp(4rem, 8vw, 8rem);
  align-items: start;
  margin: 0 auto;
  padding: 3.6rem 0 6rem;
}

.article {
  min-width: 0;
}

.article-hero {
  padding: 0.8rem 0 4rem;
  border-bottom: 1px solid var(--line);
}

.kicker,
.section-number {
  margin: 0 0 1.1rem;
  color: var(--accent);
  font-size: 0.68rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.article-hero h1 {
  max-width: 16ch;
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(3rem, 6vw, 5.65rem);
  font-weight: 400;
  line-height: 0.99;
  letter-spacing: -0.055em;
  text-wrap: balance;
}

.article-hero__dek {
  max-width: 37rem;
  margin: 1.8rem 0 0;
  color: #4c4c48;
  font-family: var(--serif);
  font-size: clamp(1.22rem, 2.2vw, 1.55rem);
  line-height: 1.45;
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  margin-top: 1.5rem;
  color: var(--faint);
  font-size: 0.78rem;
}

.article section {
  padding-top: 5rem;
}

.article section > p,
.article section > ul {
  max-width: 44rem;
}

.article p,
.article li {
  font-size: 1.02rem;
  line-height: 1.8;
}

.article p {
  margin: 1.1rem 0;
}

.article strong {
  font-weight: 700;
}

.article h2 {
  max-width: 18ch;
  margin: 0 0 1.65rem;
  font-family: var(--serif);
  font-size: clamp(2.3rem, 5vw, 4rem);
  font-weight: 400;
  line-height: 1.04;
  letter-spacing: -0.045em;
  text-wrap: balance;
}

.article h3 {
  margin: 3rem 0 0.85rem;
  font-family: var(--serif);
  font-size: clamp(1.55rem, 3vw, 2rem);
  font-weight: 400;
  line-height: 1.2;
  letter-spacing: -0.025em;
}

.lead {
  max-width: 42rem;
  margin-top: 0 !important;
  font-family: var(--serif);
  font-size: clamp(1.55rem, 3vw, 2.2rem) !important;
  line-height: 1.4 !important;
  letter-spacing: -0.025em;
}

.definition-card {
  margin: 2.5rem 0;
  padding: clamp(1.5rem, 4vw, 2.4rem);
  border-left: 4px solid var(--accent);
  background: var(--accent-soft);
}

.definition-card__label,
.insight-card__label,
.final-cta__label {
  margin: 0 0 0.8rem !important;
  color: var(--accent-dark);
  font-size: 0.65rem !important;
  font-weight: 800;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.definition-card blockquote {
  max-width: 38rem;
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(1.35rem, 3vw, 1.85rem);
  line-height: 1.4;
}

.at-a-glance {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: 3rem;
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.at-a-glance > div {
  min-height: 8rem;
  padding: 1.35rem;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.at-a-glance__label {
  display: block;
  margin-bottom: 1.1rem;
  color: var(--faint);
  font-size: 0.62rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.at-a-glance strong {
  display: block;
  max-width: 18rem;
  font-family: var(--serif);
  font-size: 1.25rem;
  font-weight: 400;
  line-height: 1.35;
}

.friction-flow {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr;
  gap: 0.8rem;
  align-items: center;
  margin: 2.8rem 0;
}

.friction-flow__step {
  min-height: 11.5rem;
  padding: 1.2rem;
  border: 1px solid var(--line);
  border-radius: 0.3rem;
  background: var(--paper);
}

.friction-flow__step span {
  display: grid;
  width: 1.8rem;
  height: 1.8rem;
  place-items: center;
  margin-bottom: 2.2rem;
  border-radius: 50%;
  color: #fff;
  background: var(--accent);
  font-size: 0.68rem;
  font-weight: 800;
}

.friction-flow__step strong,
.friction-flow__step small {
  display: block;
}

.friction-flow__step strong {
  font-family: var(--serif);
  font-size: 1.15rem;
  font-weight: 400;
}

.friction-flow__step small {
  margin-top: 0.55rem;
  color: var(--muted);
  font-size: 0.75rem;
  line-height: 1.5;
}

.friction-flow__arrow {
  color: var(--faint);
}

.pull-quote {
  margin: 3rem 0;
  padding: 2.2rem 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.pull-quote p {
  max-width: 39rem !important;
  margin: 0 !important;
  font-family: var(--serif);
  font-size: clamp(1.55rem, 3vw, 2.1rem) !important;
  line-height: 1.4 !important;
  letter-spacing: -0.025em;
}

.file-example {
  overflow: hidden;
  margin: 2.6rem 0;
  border-radius: 0.65rem;
  color: #dce8ed;
  background: var(--code);
  box-shadow: 0 22px 55px rgba(22, 32, 38, 0.16);
}

.file-example__topbar {
  display: flex;
  min-height: 3rem;
  align-items: center;
  gap: 0.42rem;
  padding: 0 1.15rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.09);
}

.file-example__topbar span {
  width: 0.56rem;
  height: 0.56rem;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.24);
}

.file-example__topbar strong {
  margin-left: 0.5rem;
  color: #93a6ae;
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 0.7rem;
  font-weight: 500;
}

.file-example pre {
  overflow-x: auto;
  margin: 0;
  padding: 1.6rem;
}

.file-example code {
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: 0.86rem;
  line-height: 1.8;
}

.file-example code span {
  color: #76c7dd;
}

.architecture {
  display: grid;
  grid-template-columns: 1.05fr 2rem 1.2fr 2rem 0.8fr;
  align-items: stretch;
  margin: 3rem 0;
  padding: 1.1rem;
  border: 1px solid var(--line);
  border-radius: 0.7rem;
  background:
    linear-gradient(rgba(49, 95, 114, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(49, 95, 114, 0.035) 1px, transparent 1px),
    var(--paper);
  background-size: 22px 22px;
}

.architecture__sources {
  display: grid;
  gap: 0.7rem;
}

.architecture-card,
.architecture__agent {
  padding: 1.15rem;
  border: 1px solid var(--line);
  border-radius: 0.45rem;
  background: rgba(255, 255, 255, 0.94);
}

.architecture-card span,
.architecture__eyebrow {
  display: block;
  margin-bottom: 1.6rem;
  color: var(--faint);
  font-size: 0.56rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.architecture-card strong,
.architecture-card small,
.architecture__agent strong,
.architecture__agent small {
  display: block;
}

.architecture-card strong,
.architecture__agent strong {
  font-family: var(--serif);
  font-size: 1.15rem;
  font-weight: 400;
}

.architecture-card small,
.architecture__agent small {
  margin-top: 0.5rem;
  color: var(--muted);
  font-size: 0.69rem;
  line-height: 1.45;
}

.architecture-card--context {
  border-top: 3px solid var(--accent);
}

.architecture-card--skill {
  border-top: 3px solid var(--warm);
}

.architecture__connector {
  display: grid;
  place-items: center;
}

.architecture__connector span {
  position: relative;
  display: block;
  width: 100%;
  height: 1px;
  background: var(--faint);
}

.architecture__connector span::after {
  position: absolute;
  top: -3px;
  right: 0;
  width: 6px;
  height: 6px;
  border-top: 1px solid var(--faint);
  border-right: 1px solid var(--faint);
  content: "";
  transform: rotate(45deg);
}

.architecture__agent {
  display: flex;
  flex-direction: column;
  justify-content: center;
  border-color: var(--accent);
  background: var(--accent-soft);
}

.architecture__loop {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-top: 1.15rem;
}

.architecture__loop span {
  padding: 0.36rem 0.55rem;
  border: 1px solid rgba(49, 95, 114, 0.22);
  border-radius: 999px;
  color: var(--accent-dark);
  font-size: 0.56rem;
  font-weight: 800;
  text-transform: uppercase;
}

.architecture__outputs {
  display: grid;
  align-content: center;
  gap: 0.55rem;
}

.architecture__outputs span {
  padding: 0.75rem;
  border: 1px solid var(--line);
  border-radius: 0.35rem;
  background: #fff;
  font-family: var(--serif);
  font-size: 0.95rem;
  text-align: center;
}

.comparison-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2.5rem;
  margin: 2.5rem 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.comparison-grid article {
  min-height: 11.5rem;
  padding: 1.5rem 0;
}

.comparison-grid article:last-child {
  border-left: 1px solid var(--line);
  padding-left: 2.5rem;
}

.comparison-grid span,
.study-sequence__label,
.before-after article > span {
  color: var(--faint);
  font-size: 0.61rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.comparison-grid h4 {
  margin: 3rem 0 0.6rem;
  font-family: var(--serif);
  font-size: 1.35rem;
  font-weight: 400;
}

.comparison-grid p {
  margin: 0;
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.6;
}

.study-sequence {
  margin: 3rem 0;
  padding: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.study-sequence > li {
  display: grid;
  grid-template-columns: 4.2rem minmax(0, 1fr);
  gap: 1.8rem;
  padding: 2.3rem 0;
  border-bottom: 1px solid var(--line);
}

.study-sequence__marker {
  display: grid;
  width: 2.5rem;
  height: 2.5rem;
  place-items: center;
  border: 1px solid var(--accent);
  border-radius: 50%;
  color: var(--accent-dark);
  font-size: 0.65rem;
  font-weight: 800;
  letter-spacing: 0.08em;
}

.study-sequence__label {
  margin: 0 0 0.65rem !important;
  color: var(--accent) !important;
  font-size: 0.61rem !important;
  line-height: 1.4 !important;
}

.study-sequence h3 {
  margin: 0;
  font-size: clamp(1.65rem, 3vw, 2.15rem);
}

.study-sequence__body > p:not(.study-sequence__label) {
  max-width: 39rem;
  margin: 0.75rem 0 0;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.7;
}

.study-sequence__evidence {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2rem;
  margin: 1.8rem 0 0;
}

.study-sequence__evidence div {
  padding-top: 0.8rem;
  border-top: 1px solid var(--soft-line);
}

.study-sequence__evidence dt {
  color: var(--faint);
  font-size: 0.61rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.study-sequence__evidence dd {
  margin: 0.55rem 0 0;
  color: #4f4f4b;
  font-family: var(--serif);
  font-size: 1.03rem;
  line-height: 1.5;
}

.result-hero {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 1.4rem;
  align-items: center;
  margin: 3rem 0 0;
  padding: 2.2rem;
  color: #fff;
  background: var(--accent-dark);
}

.result-hero > div:first-child,
.result-hero > div:last-child {
  display: grid;
}

.result-hero__value {
  font-family: var(--serif);
  font-size: clamp(2.7rem, 6vw, 4.5rem);
  line-height: 1;
  letter-spacing: -0.05em;
}

.result-hero small {
  margin-top: 0.6rem;
  color: rgba(255, 255, 255, 0.65);
  font-size: 0.62rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.result-hero__line {
  display: grid;
  align-items: center;
  grid-template-columns: 1fr;
}

.result-hero__line::before,
.result-hero__line::after {
  display: block;
  height: 1px;
  background: rgba(255, 255, 255, 0.28);
  content: "";
}

.result-hero__line span {
  padding: 0.55rem 0;
  color: rgba(255, 255, 255, 0.62);
  font-size: 0.58rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-align: center;
  text-transform: uppercase;
}

.figure-note {
  margin: 0.65rem 0 3rem !important;
  color: var(--faint);
  font-size: 0.7rem !important;
  line-height: 1.5 !important;
}

.evidence-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 2.5rem;
  margin: 2.8rem 0;
  border-top: 1px solid var(--line);
}

.evidence-grid article {
  min-height: 11rem;
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--line);
}

.evidence-grid article > span {
  display: block;
  color: var(--accent);
  font-family: var(--serif);
  font-size: 2.2rem;
  letter-spacing: -0.04em;
}

.evidence-grid strong {
  display: block;
  margin-top: 2.2rem;
  font-family: var(--serif);
  font-size: 1.15rem;
  font-weight: 400;
}

.evidence-grid p {
  margin: 0.35rem 0 0;
  color: var(--muted);
  font-size: 0.75rem;
  line-height: 1.5;
}

.insight-card {
  margin: 3rem 0;
  padding: 1.7rem;
  border: 1px solid var(--accent);
  background: var(--accent-soft);
}

.insight-card p:last-child {
  max-width: 35rem;
  margin: 0;
  font-family: var(--serif);
  font-size: 1.45rem;
  line-height: 1.45;
}

.learning-loop {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.55rem;
  margin: 2.8rem 0;
}

.learning-loop > div {
  position: relative;
  min-height: 12rem;
  padding: 1rem;
  border: 1px solid var(--line);
  background: var(--paper);
}

.learning-loop > div:not(:last-child)::after {
  position: absolute;
  z-index: 2;
  top: 50%;
  right: -0.82rem;
  display: grid;
  width: 1.05rem;
  height: 1.05rem;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 50%;
  color: var(--muted);
  background: var(--page);
  content: "›";
  font-size: 0.72rem;
  transform: translateY(-50%);
}

.learning-loop span {
  display: grid;
  width: 1.7rem;
  height: 1.7rem;
  place-items: center;
  border-radius: 50%;
  color: #fff;
  background: var(--accent);
  font-size: 0.63rem;
  font-weight: 800;
}

.learning-loop strong,
.learning-loop small {
  display: block;
}

.learning-loop strong {
  margin-top: 2.7rem;
  font-family: var(--serif);
  font-size: 1.15rem;
  font-weight: 400;
}

.learning-loop small {
  margin-top: 0.55rem;
  color: var(--muted);
  font-size: 0.68rem;
  line-height: 1.5;
}

.before-after {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 1rem;
  align-items: center;
  margin: 2.8rem 0;
}

.before-after article {
  min-height: 18rem;
  padding: 1.5rem;
  border: 1px solid var(--line);
  background: var(--warm-soft);
}

.before-after article:last-child {
  background: var(--accent-soft);
}

.before-after h3 {
  margin: 3.5rem 0 1rem;
  font-size: 1.5rem;
}

.before-after ul {
  margin: 0;
  padding-left: 1.1rem;
}

.before-after li {
  margin: 0.45rem 0;
  color: var(--muted);
  font-size: 0.77rem;
  line-height: 1.5;
}

.before-after__arrow {
  color: var(--faint);
}

.score-card {
  display: grid;
  grid-template-columns: 9rem 1fr;
  gap: 1.8rem;
  align-items: center;
  margin: 3rem 0;
  padding: 1.7rem;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.score-card > div {
  display: grid;
}

.score-card__score {
  color: var(--warm);
  font-family: var(--serif);
  font-size: 3.8rem;
  line-height: 1;
  letter-spacing: -0.05em;
}

.score-card__out-of {
  margin-top: 0.4rem;
  color: var(--faint);
  font-size: 0.62rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.score-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.65;
}

.boundary-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.8rem;
  margin: 2.6rem 0;
}

.boundary-grid article {
  padding: 1.5rem;
  border: 1px solid var(--line);
  background: var(--paper);
}

.boundary-grid article > p {
  margin: 0 0 2.5rem;
  font-family: var(--serif);
  font-size: 1.4rem;
  line-height: 1.3;
}

.boundary-grid ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.boundary-grid li {
  position: relative;
  margin: 0.6rem 0;
  padding-left: 1.4rem;
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.5;
}

.boundary-grid li::before {
  position: absolute;
  left: 0;
  content: "✓";
  color: var(--accent);
  font-weight: 800;
}

.boundary-grid__cannot li::before {
  content: "×";
  color: var(--warm);
}

.final-cta {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2rem;
  align-items: end;
  margin-top: 3rem;
  padding: clamp(1.6rem, 4vw, 2.6rem);
  color: #fff;
  background: var(--code);
}

.final-cta h2 {
  margin-bottom: 0.7rem;
  font-size: clamp(2rem, 4vw, 3rem);
}

.final-cta p:not(.final-cta__label) {
  max-width: 31rem;
  margin: 0;
  color: rgba(255, 255, 255, 0.68);
  font-size: 0.84rem;
  line-height: 1.6;
}

.final-cta__label {
  color: #88c4d5;
}

.final-cta > a {
  display: inline-flex;
  min-height: 3.2rem;
  align-items: center;
  gap: 1.2rem;
  padding: 0.8rem 1rem 0.8rem 1.2rem;
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 999px;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.07em;
  text-decoration: none;
  text-transform: uppercase;
  white-space: nowrap;
}

.final-cta > a:hover,
.final-cta > a:focus-visible {
  background: rgba(255, 255, 255, 0.1);
}

.final-cta svg {
  width: 1rem;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.5;
}

.article-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  margin-top: 5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
}

.article-footer p {
  max-width: 29rem;
  margin: 0;
  color: var(--faint);
  font-size: 0.7rem;
  line-height: 1.5;
}

.article-footer a {
  color: var(--muted);
  font-size: 0.72rem;
}

.desktop-toc {
  position: sticky;
  top: 2.5rem;
}

.desktop-toc > div {
  padding: 1.3rem;
  border: 1px solid rgba(255, 255, 255, 0.74);
  border-radius: 1.15rem;
  background: rgba(255, 255, 255, 0.52);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.9),
    0 18px 48px rgba(35, 49, 54, 0.09);
  backdrop-filter: blur(22px) saturate(150%);
  -webkit-backdrop-filter: blur(22px) saturate(150%);
}

.desktop-toc > div > p {
  margin: 0 0 1.2rem;
  color: var(--faint);
  font-family: var(--serif);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.desktop-toc nav {
  display: grid;
  gap: 0.75rem;
}

.desktop-toc nav a {
  position: relative;
  color: #aaa9a3;
  font-size: 0.72rem;
  line-height: 1.35;
  text-decoration: none;
  transition: color 150ms ease;
}

.desktop-toc nav a:hover,
.desktop-toc nav a:focus-visible,
.desktop-toc nav a.is-active {
  color: var(--ink);
}

.desktop-toc nav a.is-active::before {
  position: absolute;
  top: 0.28rem;
  left: -1.3rem;
  width: 0.35rem;
  height: 0.35rem;
  border-radius: 50%;
  background: var(--accent);
  content: "";
}

.desktop-toc__chat {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 1.6rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  color: var(--accent-dark);
  font-size: 0.7rem;
  font-weight: 800;
  text-decoration: none;
}

.mobile-toc {
  display: none;
}

@media (max-width: 980px) {
  .page-shell {
    grid-template-columns: minmax(0, 1fr);
  }

  .desktop-toc {
    display: none;
  }

  .mobile-toc {
    display: block;
    margin-top: 1.5rem;
    border: 1px solid rgba(255, 255, 255, 0.78);
    border-radius: 1rem;
    background: rgba(255, 255, 255, 0.56);
    box-shadow:
      inset 0 1px 0 rgba(255, 255, 255, 0.9),
      0 16px 38px rgba(35, 49, 54, 0.08);
    backdrop-filter: blur(20px) saturate(145%);
    -webkit-backdrop-filter: blur(20px) saturate(145%);
  }

  .mobile-toc summary {
    padding: 1rem;
    cursor: pointer;
    font-size: 0.75rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
  }

  .mobile-toc nav {
    display: grid;
    padding: 0 1rem 1rem;
  }

  .mobile-toc a {
    padding: 0.55rem 0;
    border-top: 1px solid var(--soft-line);
    color: var(--muted);
    font-size: 0.78rem;
    text-decoration: none;
  }

  .mobile-toc a.is-active {
    color: var(--ink);
    font-weight: 700;
  }
}

@media (max-width: 720px) {
  .site-header__inner,
  .page-shell {
    width: min(100% - 2rem, 1120px);
  }

  .site-nav {
    gap: 1rem;
  }

  .site-nav a:first-child {
    display: none;
  }

  .page-shell {
    padding-top: 2rem;
  }

  .article-hero {
    padding-bottom: 3rem;
  }

  .article-hero h1 {
    font-size: clamp(2.85rem, 13vw, 4.5rem);
  }

  .article section {
    padding-top: 4rem;
  }

  .at-a-glance,
  .comparison-grid,
  .evidence-grid,
  .boundary-grid {
    grid-template-columns: 1fr;
  }

  .friction-flow {
    grid-template-columns: 1fr;
  }

  .friction-flow__step {
    min-height: 9.5rem;
  }

  .friction-flow__step span {
    margin-bottom: 1.3rem;
  }

  .friction-flow__arrow {
    text-align: center;
    transform: rotate(90deg);
  }

  .architecture {
    grid-template-columns: 1fr;
    gap: 0.7rem;
  }

  .architecture__connector {
    min-height: 1.5rem;
  }

  .architecture__connector span {
    width: 1px;
    height: 100%;
  }

  .architecture__connector span::after {
    top: auto;
    right: -3px;
    bottom: 0;
    transform: rotate(135deg);
  }

  .architecture__outputs {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .architecture__outputs span {
    padding: 0.65rem 0.25rem;
    font-size: 0.76rem;
  }

  .comparison-grid article:last-child {
    border-left: 0;
    border-top: 1px solid var(--line);
    padding-left: 0;
  }

  .study-sequence > li {
    grid-template-columns: 3rem minmax(0, 1fr);
    gap: 1rem;
  }

  .study-sequence__evidence {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .result-hero {
    grid-template-columns: 1fr;
    gap: 1.2rem;
  }

  .result-hero__line {
    display: none;
  }

  .result-hero > div:last-child {
    padding-top: 1.2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.24);
  }

  .learning-loop {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .learning-loop > div:nth-child(2)::after {
    display: none;
  }

  .before-after {
    grid-template-columns: 1fr;
  }

  .before-after__arrow {
    text-align: center;
    transform: rotate(90deg);
  }

  .score-card {
    grid-template-columns: 1fr;
  }

  .final-cta {
    grid-template-columns: 1fr;
    align-items: start;
  }

  .final-cta > a {
    justify-self: start;
  }

  .article-footer {
    display: grid;
  }
}

@media (max-width: 430px) {
  .site-nav__chat {
    padding: 0.58rem 0.75rem;
  }

  .article-meta span:nth-child(2),
  .article-meta span:nth-child(4) {
    display: none;
  }

  .article-meta {
    display: grid;
    gap: 0.3rem;
  }

  .learning-loop {
    grid-template-columns: 1fr;
  }

  .learning-loop > div {
    min-height: 9.5rem;
  }

  .learning-loop > div:not(:last-child)::after {
    top: auto;
    right: 50%;
    bottom: -0.82rem;
    content: "⌄";
    transform: translateX(50%);
  }

  .learning-loop > div:nth-child(2)::after {
    display: grid;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}