:root {
  color-scheme: light;
  --bg: #f7f7f5;
  --text: #1c1c1c;
  --muted: #686862;
  --line: #d9d9d5;
  --focus: #255db3;

  /* Desktop keeps the editorial left edge while using the available canvas. */
  --site-max: 88rem;
  --reading-max: 72rem;

  --space-3xs: clamp(0.25rem, 0.21rem + 0.2vw, 0.375rem);
  --space-2xs: clamp(0.5rem, 0.46rem + 0.2vw, 0.625rem);
  --space-xs: clamp(0.75rem, 0.66rem + 0.44vw, 1rem);
  --space-s: clamp(1rem, 0.96rem + 0.22vw, 1.125rem);
  --space-m: clamp(1.5rem, 1.33rem + 0.87vw, 2rem);
  --space-l: clamp(2rem, 1.65rem + 1.74vw, 3rem);
  --space-xl: clamp(3rem, 2.3rem + 3.48vw, 5rem);
  --space-2xl: clamp(4.5rem, 3.4rem + 5.2vw, 7.5rem);
  --gutter: clamp(1rem, 0.65rem + 1.75vw, 2rem);

  --step--1: clamp(0.8125rem, 0.785rem + 0.14vw, 0.875rem);
  --step-0: clamp(1rem, 0.956rem + 0.22vw, 1.125rem);
  --step-1: clamp(1.25rem, 1.16rem + 0.44vw, 1.5rem);
  --step-2: clamp(1.5rem, 1.35rem + 0.74vw, 1.925rem);
  --step-3: clamp(2.25rem, 1.99rem + 1.3vw, 3rem);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  background: var(--bg);
  color: var(--text);
  scroll-behavior: smooth;
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Noto Sans JP", sans-serif;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body {
  margin: 0;
  min-width: 0;
  background: var(--bg);
}

a {
  color: inherit;
  text-underline-offset: 0.22em;
  text-decoration-thickness: 1px;
}

a:hover {
  text-decoration-color: currentColor;
}

a:focus-visible,
button:focus-visible,
textarea:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 4px;
}

h1,
h2,
h3,
p,
blockquote {
  margin-block-start: 0;
}

.site-header__inner,
.page,
.site-footer__inner {
  width: min(100%, calc(var(--site-max) + (var(--gutter) * 2)));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.site-header {
  border-block-end: 1px solid var(--line);
}

.site-header__inner {
  min-height: 3.5rem;
  display: flex;
  align-items: center;
}

.site-title {
  font-size: var(--step--1);
  font-weight: 700;
  letter-spacing: 0.04em;
  text-decoration: none;
}

.page {
  padding-block: var(--space-xl) var(--space-2xl);
}

.page > article,
.page > .hero:not(:has(+ .card-grid)),
.page > section:not(.card-grid):not(.method) {
  max-width: var(--reading-max);
}

article {
  max-width: var(--reading-max);
}

.hero {
  margin-block-end: var(--space-xl);
}

.eyebrow {
  margin-block-end: var(--space-xs);
  color: var(--muted);
  font-size: var(--step--1);
  font-weight: 700;
  letter-spacing: 0.06em;
}

h1 {
  margin-block-end: var(--space-s);
  font-size: var(--step-3);
  line-height: 1.08;
  letter-spacing: -0.035em;
}

h2 {
  margin-block-start: var(--space-xl);
  margin-block-end: var(--space-s);
  padding-block-start: var(--space-m);
  border-block-start: 1px solid var(--line);
  font-size: var(--step-1);
  line-height: 1.35;
  letter-spacing: -0.02em;
}

h3 {
  margin-block-start: var(--space-l);
  margin-block-end: var(--space-xs);
  font-size: var(--step-0);
  line-height: 1.45;
}

p,
li {
  font-size: var(--step-0);
}

p {
  margin-block-end: var(--space-s);
}

li + li {
  margin-block-start: var(--space-2xs);
}

.lead {
  color: var(--muted);
  font-size: var(--step-1);
  line-height: 1.6;
  letter-spacing: -0.01em;
}

.method-name {
  display: block;
  margin-block-start: var(--space-3xs);
  color: var(--muted);
  font-size: 0.62em;
  font-weight: 500;
  line-height: 1.45;
  letter-spacing: 0;
}

.card-grid {
  margin-block: var(--space-l) var(--space-xl);
  border-block-start: 1px solid var(--line);
}

.card-link {
  display: grid;
  grid-template-columns: minmax(12rem, 0.9fr) minmax(0, 1.5fr);
  column-gap: var(--space-l);
  padding-block: var(--space-m);
  border-block-end: 1px solid var(--line);
  text-decoration: none;
}

.card-link:hover strong,
.card-link:focus-visible strong {
  text-decoration: underline;
  text-underline-offset: 0.22em;
  text-decoration-thickness: 1px;
}

.card-link strong,
.card-link span {
  display: block;
}

.card-link strong {
  font-size: var(--step-1);
  line-height: 1.35;
  letter-spacing: -0.02em;
}

.card-link .method-name {
  grid-column: 1;
  margin-block-start: var(--space-3xs);
  font-size: var(--step--1);
}

.card-link > span:last-child {
  grid-column: 2;
  grid-row: 1 / span 2;
  align-self: start;
  color: var(--muted);
  font-size: var(--step-0);
}

.method {
  max-width: var(--reading-max);
  margin-block: 0;
  padding-block: var(--space-l);
  border-block-start: 1px solid var(--line);
}

.method + .method {
  margin-block-start: 0;
}

.method h2 {
  margin-block-start: 0 !important;
  padding-block-start: 0;
  border: 0;
}

.callout {
  margin-block: var(--space-l);
  padding-block: var(--space-s);
  border-block: 1px solid var(--line);
}

.callout strong {
  font-weight: 700;
}

blockquote {
  margin-block: var(--space-l);
  padding-inline-start: var(--space-m);
  border-inline-start: 1px solid var(--line);
}

code {
  font-size: 0.92em;
  overflow-wrap: anywhere;
}

ol,
ul {
  padding-inline-start: 1.35rem;
}

.evidence {
  margin-block-start: var(--space-m);
  color: var(--muted);
  font-size: var(--step--1);
  overflow-wrap: anywhere;
}

.evidence-summary {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-block: var(--space-l);
  border-block-start: 1px solid var(--line);
}

.evidence-summary > div {
  min-width: 0;
  padding-block: var(--space-s);
  border-block-end: 1px solid var(--line);
}

.evidence-summary > div:nth-child(odd) {
  padding-inline-end: var(--space-m);
}

.evidence-summary > div:nth-child(even) {
  padding-inline-start: var(--space-m);
  border-inline-start: 1px solid var(--line);
}

.evidence-summary strong,
.evidence-summary span {
  display: block;
}

.evidence-summary strong {
  margin-block-end: var(--space-3xs);
  color: var(--muted);
  font-size: var(--step--1);
}

.references {
  padding-inline-start: 1.25rem;
}

.references li + li {
  margin-block-start: var(--space-s);
}

.references a {
  font-weight: 600;
}

.prompt-label {
  display: block;
  margin-block: var(--space-m) var(--space-xs);
  font-size: var(--step--1);
  font-weight: 700;
  letter-spacing: 0.04em;
}

.prompt-box {
  width: 100%;
  min-height: 11rem;
  resize: vertical;
  padding: var(--space-s);
  border: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-size: var(--step--1);
  line-height: 1.7;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-m);
  margin-block: var(--space-s) var(--space-xs);
}

.button {
  appearance: none;
  min-height: 44px;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-weight: 700;
  line-height: 44px;
  text-decoration: underline;
  text-decoration-color: color-mix(in srgb, currentColor 45%, transparent);
  text-underline-offset: 0.24em;
  cursor: pointer;
}

.button:hover {
  text-decoration-color: currentColor;
}

.button--secondary {
  background: transparent;
  color: var(--text);
}

.copy-status {
  min-height: 1.6em;
  margin-block-start: var(--space-2xs);
  color: var(--muted);
  font-size: var(--step--1);
}

.site-footer {
  border-block-start: 1px solid var(--line);
}

.site-footer__inner {
  padding-block: var(--space-s);
  color: var(--muted);
  font-size: var(--step--1);
}

.site-footer__inner p {
  font-size: inherit;
}

.skip-link {
  position: absolute;
  left: -9999px;
}

.skip-link:focus {
  left: var(--gutter);
  top: var(--space-s);
  z-index: 100;
  padding: var(--space-2xs) var(--space-xs);
  border: 1px solid var(--line);
  background: var(--bg);
}

/* Smartphone layout: deliberately separate from the desktop editorial layout. */
@media (max-width: 700px) {
  :root {
    --gutter: 1rem;

    /* Fixed mobile rhythm avoids fluid values feeling oversized on narrow screens. */
    --space-s: 1rem;
    --space-m: 1.25rem;
    --space-l: 1.5rem;
    --space-xl: 2.25rem;
    --space-2xl: 3rem;

    --step--1: 0.8125rem;
    --step-0: 1rem;
    --step-1: 1.125rem;
    --step-2: 1.375rem;
    --step-3: 1.875rem;
  }

  html {
    line-height: 1.68;
  }

  .site-header__inner {
    min-height: 3rem;
  }

  .page {
    padding-block: var(--space-l) var(--space-2xl);
  }

  .hero {
    margin-block-end: var(--space-xl);
  }

  h1 {
    max-width: none;
    margin-block-end: var(--space-s);
    font-size: var(--step-3);
    line-height: 1.22;
    letter-spacing: -0.025em;
  }

  h2 {
    margin-block-start: var(--space-xl);
    padding-block-start: var(--space-l);
    font-size: var(--step-1);
    line-height: 1.45;
  }

  h3 {
    margin-block-start: var(--space-l);
    font-size: var(--step-0);
  }

  .lead {
    max-width: 42ch;
    font-size: var(--step-0);
    line-height: 1.72;
    letter-spacing: 0;
  }

  .card-grid {
    margin-block: var(--space-l) var(--space-xl);
  }

  .card-link {
    grid-template-columns: minmax(0, 1fr);
    row-gap: var(--space-2xs);
    padding-block: var(--space-m);
  }

  .card-link strong {
    font-size: var(--step-1);
    line-height: 1.45;
  }

  .card-link .method-name,
  .card-link > span:last-child {
    grid-column: 1;
    grid-row: auto;
  }

  .card-link > span:last-child {
    font-size: var(--step-0);
    line-height: 1.68;
  }

  .method {
    padding-block: var(--space-l);
  }

  .evidence-summary {
    grid-template-columns: minmax(0, 1fr);
  }

  .evidence-summary > div:nth-child(odd),
  .evidence-summary > div:nth-child(even) {
    padding-inline: 0;
    border-inline-start: 0;
  }

  ol,
  ul,
  .references {
    padding-inline-start: 1.2rem;
  }

  .actions {
    gap: var(--space-s);
  }

  .button {
    min-height: 48px;
    line-height: 48px;
  }

  .prompt-box {
    min-height: 10rem;
    font-size: var(--step-0);
  }

  .site-footer__inner {
    padding-block: var(--space-s);
    line-height: 1.5;
  }
}

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


/* Site-wide information architecture */
.site-header__inner {
  justify-content: space-between;
  gap: var(--space-m);
}

.global-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-s);
  font-size: var(--step--1);
}

.global-nav a {
  text-decoration: none;
}

.global-nav a:hover,
.global-nav a:focus-visible,
.global-nav a[aria-current="page"] {
  text-decoration: underline;
  text-underline-offset: 0.24em;
}

.home-hero {
  max-width: var(--reading-max);
}

.home-actions {
  max-width: var(--reading-max);
}

.home-secondary,
.home-boundary {
  max-width: var(--reading-max);
}

.inline-toc {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs) var(--space-m);
  margin-block: var(--space-l);
  padding-block: var(--space-s);
  border-block: 1px solid var(--line);
}

@media (max-width: 700px) {
  .site-header__inner {
    align-items: flex-start;
    flex-direction: column;
    gap: var(--space-xs);
    padding-block: var(--space-xs);
  }

  .global-nav {
    gap: var(--space-xs) var(--space-s);
    line-height: 1.4;
  }
}


/* Breadcrumbs */
.breadcrumbs {
  max-width: var(--reading-max);
  margin-block: 0 var(--space-l);
  color: var(--muted);
  font-size: var(--step--1);
}

.breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2xs);
  margin: 0;
  padding: 0;
  list-style: none;
}

.breadcrumbs li {
  font-size: inherit;
}

.breadcrumbs li + li::before {
  content: "/";
  margin-inline-end: var(--space-2xs);
  color: var(--line);
}

.breadcrumbs [aria-current="page"] {
  color: var(--text);
}

@media (max-width: 700px) {
  .breadcrumbs {
    margin-block-end: var(--space-m);
  }
}

/* Global footer policy: keep the rendered footer limited to About. */
.site-footer__links > a:not([href="/about/"]),
.site-footer__inner > p {
  display: none;
}

.site-footer__links {
  margin-block-end: 0;
}