* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg: #f8f9fb;
  --surface: #ffffff;
  --ink: #111827;
  --muted: #4b5563;
  --subtle: #667085;
  --border: rgba(17, 24, 39, 0.09);
  --teal: #0e7490;
  --teal-soft: rgba(14, 116, 144, 0.07);
  --domain: #0e7490;
  --domain-soft: rgba(14, 116, 144, 0.07);
  --head: "Plus Jakarta Sans", system-ui, sans-serif;
  --body: "Inter", system-ui, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, monospace;
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 12px;
  --space-lg: 16px;
  --space-xl: 24px;
  --space-2xl: 32px;
  --space-3xl: 48px;
  --space-4xl: 64px;
  --space-5xl: 96px;
  --radius: 12px;
  --radius-lg: 18px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

html {
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--body);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--teal);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

a:hover {
  text-decoration-thickness: 2px;
}

a:focus-visible,
button:focus-visible {
  outline: 3px solid var(--domain);
  outline-offset: 4px;
}

.skip-link {
  background: var(--ink);
  color: #ffffff;
  font-size: 13px;
  font-weight: 700;
  left: 12px;
  padding: 10px 14px;
  position: fixed;
  top: -80px;
  z-index: 1000;
}

.skip-link:focus {
  top: 12px;
}

.wrap {
  margin: 0 auto;
  max-width: 1040px;
  padding-inline: clamp(20px, 6vw, 64px);
}

.narrow {
  margin: 0 auto;
  max-width: 760px;
}

.np-bar {
  align-items: center;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  background: rgba(248, 249, 251, 0.94);
  border-bottom: 1px solid var(--border);
  display: grid;
  font-size: 13px;
  grid-template-columns: 1fr auto 1fr;
  height: 52px;
  inset: 0 0 auto;
  padding-inline: clamp(16px, 4vw, 32px);
  position: fixed;
  z-index: 100;
}

.np-brand {
  align-items: center;
  color: var(--ink);
  display: inline-flex;
  font-family: var(--head);
  font-size: 15px;
  font-weight: 700;
  gap: var(--space-sm);
  justify-self: start;
  letter-spacing: -0.01em;
  min-height: 44px;
  text-decoration: none;
}

.np-brand img {
  height: auto;
  width: 24px;
}

.np-links {
  align-items: center;
  display: flex;
  gap: var(--space-xs);
  justify-self: center;
}

.np-links a,
.np-lang a,
.np-lang span {
  align-items: center;
  border-radius: 7px;
  color: var(--muted);
  display: inline-flex;
  font-weight: 600;
  justify-content: center;
  min-height: 44px;
  padding-inline: 10px;
  text-decoration: none;
}

.np-links a:hover,
.np-lang a:hover {
  background: rgba(17, 24, 39, 0.04);
  color: var(--ink);
}

.np-right {
  align-items: center;
  display: flex;
  gap: var(--space-sm);
  justify-self: end;
}

.np-lang {
  align-items: center;
  display: flex;
  font-size: 12px;
  font-weight: 700;
}

.np-lang .active {
  color: var(--domain);
  min-width: 34px;
  padding-inline: 6px;
}

.np-lang .separator {
  color: var(--subtle);
  min-height: auto;
  padding: 0;
}

.nav-signin {
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--muted);
  display: inline-flex;
  font-family: var(--head);
  font-size: 12px;
  font-weight: 700;
  justify-content: center;
  min-height: 36px;
  padding: 6px 14px;
  text-decoration: none;
}

.nav-signin:hover {
  border-color: rgba(17, 24, 39, 0.24);
  color: var(--ink);
  text-decoration: none;
}

.hero {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 132px 0 72px;
}

.hero-grid {
  align-items: center;
  display: grid;
  gap: clamp(40px, 7vw, 72px);
  grid-template-columns: minmax(0, 1.08fr) minmax(300px, 0.92fr);
}

.eyebrow,
.section-label {
  color: var(--domain);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

.eyebrow {
  align-items: center;
  display: inline-flex;
  gap: var(--space-sm);
  margin-bottom: 20px;
}

.eyebrow::before {
  background: var(--domain);
  border-radius: 2px;
  content: "";
  height: 2px;
  width: 20px;
}

.hero h1 {
  font-family: var(--head);
  font-size: clamp(34px, 5vw, 52px);
  font-weight: 750;
  letter-spacing: -0.045em;
  line-height: 1.06;
  max-width: 16ch;
}

.hero h1 em {
  color: var(--domain);
  font-style: normal;
}

.article-meta {
  color: var(--subtle);
  font-size: 12.5px;
  line-height: 1.6;
  margin-top: 18px;
  max-width: 68ch;
}

.hero-lead {
  color: var(--muted);
  font-size: 17px;
  line-height: 1.72;
  margin-top: 20px;
  max-width: 64ch;
}

.hero-lead strong {
  color: var(--ink);
  font-weight: 650;
}

.hero-actions {
  align-items: center;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  margin-top: 28px;
}

.button-primary,
.button-secondary {
  align-items: center;
  border-radius: 999px;
  display: inline-flex;
  font-family: var(--head);
  font-size: 14px;
  font-weight: 700;
  gap: var(--space-sm);
  justify-content: center;
  min-height: 48px;
  padding: 12px 22px;
  text-decoration: none;
  transition: transform 160ms var(--ease), border-color 160ms ease, background 160ms ease;
}

.button-primary {
  background: var(--domain);
  border: 1px solid var(--domain);
  color: #ffffff;
}

.button-primary:hover {
  color: #ffffff;
  text-decoration: none;
  transform: translateY(-1px);
}

.button-secondary {
  background: transparent;
  border: 1px solid rgba(17, 24, 39, 0.16);
  color: var(--ink);
}

.button-secondary:hover {
  background: var(--domain-soft);
  border-color: var(--domain);
  text-decoration: none;
}

.hero-facts {
  color: var(--subtle);
  display: flex;
  flex-wrap: wrap;
  font-size: 12.5px;
  gap: 10px 22px;
  margin-top: 22px;
}

.hero-facts span {
  align-items: center;
  display: inline-flex;
  gap: 7px;
}

.hero-facts span::before {
  background: var(--domain);
  border-radius: 50%;
  content: "";
  height: 6px;
  width: 6px;
}

.concept-panel {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  padding: 28px;
}

.concept-kicker {
  color: var(--subtle);
  font-family: var(--head);
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

.memory-line,
.speed-line {
  align-items: center;
  display: flex;
  gap: clamp(6px, 1.3vw, 12px);
  justify-content: center;
  margin: 28px 0 24px;
}

.memory-line b,
.speed-line b {
  align-items: center;
  background: var(--surface);
  border: 1px solid rgba(79, 70, 229, 0.24);
  border-radius: 10px;
  color: var(--ink);
  display: inline-flex;
  font-family: var(--mono);
  font-size: clamp(21px, 4vw, 30px);
  height: clamp(50px, 7vw, 64px);
  justify-content: center;
  width: clamp(46px, 7vw, 60px);
}

.speed-line b {
  border-color: rgba(14, 116, 144, 0.22);
  font-size: clamp(18px, 3vw, 24px);
}

.concept-rule {
  border-top: 1px solid var(--border);
  display: grid;
  gap: var(--space-sm);
  grid-template-columns: 1fr 1fr 1fr;
  padding-top: 18px;
}

.concept-rule div {
  min-width: 0;
}

.concept-rule strong {
  color: var(--ink);
  display: block;
  font-family: var(--head);
  font-size: 12px;
  margin-bottom: 2px;
}

.concept-rule span {
  color: var(--subtle);
  display: block;
  font-size: 11px;
  line-height: 1.5;
}

.stroop-sample {
  display: grid;
  gap: 10px;
  margin: 26px 0 22px;
  place-items: center;
}

.stroop-sample strong {
  font-family: var(--head);
  font-size: clamp(34px, 6vw, 52px);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1;
}

.stroop-sample span {
  color: var(--subtle);
  font-size: 12px;
}

.band {
  padding: clamp(56px, 8vw, 80px) 0;
}

.band-white {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.band-gray {
  background: var(--bg);
}

.section-label {
  display: block;
  margin-bottom: 12px;
}

.section-title {
  font-family: var(--head);
  font-size: clamp(25px, 3.4vw, 34px);
  font-weight: 750;
  letter-spacing: -0.035em;
  line-height: 1.18;
  max-width: 25ch;
}

.section-intro,
.prose p {
  color: var(--muted);
  font-size: 15.5px;
  line-height: 1.82;
  max-width: 72ch;
}

.section-intro {
  margin-top: 14px;
}

.prose {
  display: grid;
  gap: var(--space-lg);
}

.prose h3 {
  font-family: var(--head);
  font-size: 19px;
  letter-spacing: -0.02em;
  line-height: 1.3;
  margin-top: 18px;
}

.evidence-note {
  background: var(--domain-soft);
  border: 1px solid color-mix(in srgb, var(--domain) 24%, transparent);
  border-radius: var(--radius);
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.72;
  margin-top: 26px;
  padding: 18px 20px;
}

.evidence-note strong {
  color: var(--ink);
}

.task-grid {
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  margin-top: 30px;
}

.task-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  min-height: 220px;
  padding: 22px;
}

.task-card.featured {
  background: var(--domain-soft);
  border-color: color-mix(in srgb, var(--domain) 26%, transparent);
}

.task-index {
  color: var(--domain);
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 700;
}

.task-card h3 {
  font-family: var(--head);
  font-size: 18px;
  letter-spacing: -0.02em;
  line-height: 1.25;
}

.task-card p {
  color: var(--muted);
  flex: 1;
  font-size: 13.5px;
  line-height: 1.7;
}

.task-links {
  align-items: center;
  display: flex;
  flex-wrap: wrap;
  font-family: var(--head);
  font-size: 12.5px;
  font-weight: 700;
  gap: 10px 18px;
}

.limits-grid {
  display: grid;
  gap: 18px;
  grid-template-columns: 1fr 1fr;
  margin-top: 30px;
}

.limit-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

.limit-panel h3 {
  font-family: var(--head);
  font-size: 16px;
  margin-bottom: 12px;
}

.limit-panel ul {
  color: var(--muted);
  display: grid;
  font-size: 13.5px;
  gap: 10px;
  line-height: 1.65;
  padding-left: 19px;
}

.limit-panel li::marker {
  color: var(--domain);
}

.steps {
  counter-reset: steps;
  display: grid;
  gap: 12px;
  list-style: none;
  margin-top: 28px;
}

.steps li {
  align-items: start;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--muted);
  display: grid;
  font-size: 14px;
  gap: 14px;
  grid-template-columns: 34px 1fr;
  line-height: 1.7;
  padding: 18px 20px;
}

.steps li::before {
  align-items: center;
  background: var(--domain-soft);
  border-radius: 50%;
  color: var(--domain);
  content: counter(steps);
  counter-increment: steps;
  display: inline-flex;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 800;
  height: 34px;
  justify-content: center;
  width: 34px;
}

.steps strong {
  color: var(--ink);
}

.source-list {
  display: grid;
  gap: 12px;
  margin-top: 24px;
  padding-left: 20px;
}

.source-list li {
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.65;
  padding-left: 4px;
}

.source-list li::marker {
  color: var(--domain);
}

.related-links {
  align-items: center;
  border-top: 1px solid var(--border);
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
  margin-top: 38px;
  padding-top: 22px;
}

.related-links strong {
  font-family: var(--head);
  font-size: 12px;
}

.related-links a {
  font-size: 13px;
  font-weight: 650;
}

.final-cta {
  align-items: center;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  display: flex;
  flex-wrap: wrap;
  gap: 28px;
  justify-content: space-between;
  padding: clamp(26px, 5vw, 42px);
}

.final-cta div {
  flex: 1 1 360px;
}

.final-cta h2 {
  font-family: var(--head);
  font-size: clamp(22px, 3vw, 28px);
  letter-spacing: -0.03em;
  line-height: 1.2;
}

.final-cta p {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.7;
  margin-top: 10px;
  max-width: 64ch;
}

.site-footer {
  background: #111827;
  color: #ffffff;
}

.footer-inner {
  align-items: center;
  display: flex;
  flex-wrap: wrap;
  gap: 20px 32px;
  justify-content: space-between;
  padding-bottom: 28px;
  padding-top: 32px;
}

.footer-brand {
  align-items: center;
  color: #ffffff;
  display: inline-flex;
  font-family: var(--head);
  font-size: 14px;
  font-weight: 700;
  gap: 8px;
  text-decoration: none;
}

.footer-brand img {
  filter: brightness(0) invert(1);
  height: auto;
  width: 22px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 22px;
}

.footer-links a {
  color: rgba(255, 255, 255, 0.78);
  font-size: 12.5px;
  text-decoration: none;
}

.footer-links a:hover {
  color: #ffffff;
  text-decoration: underline;
}

.footer-note {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  color: rgba(255, 255, 255, 0.68);
  font-size: 11.5px;
  line-height: 1.65;
  padding: 18px 0 24px;
  text-align: center;
}

@media (max-width: 820px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }

  .concept-panel {
    max-width: 620px;
  }
}

@media (max-width: 700px) {
  .np-links {
    display: none;
  }

  .np-bar {
    grid-template-columns: 1fr auto;
  }

  .limits-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 460px) {
  .np-bar {
    padding-inline: 10px;
  }

  .np-right {
    gap: 2px;
  }

  .nav-signin {
    padding-inline: 10px;
  }

  .hero {
    padding-bottom: 56px;
    padding-top: 112px;
  }

  .hero h1 {
    font-size: clamp(31px, 10vw, 42px);
  }

  .concept-panel {
    padding: 22px 18px;
  }

  .concept-rule {
    gap: 12px;
    grid-template-columns: 1fr;
  }

  .task-grid {
    grid-template-columns: 1fr;
  }

  .footer-inner {
    align-items: flex-start;
    flex-direction: column;
  }
}

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

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