:root {
  --paper: #ffffff;
  --ink: #111111;
  --muted: #656565;
  --rule: #d9d9d9;
  --soft: #f3f3f3;
  --content-width: 920px;
  font-synthesis: none;
}

* { box-sizing: border-box; }

html {
  background: var(--paper);
  color: var(--ink);
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family:
    "Hiragino Mincho ProN", "Hiragino Mincho Pro",
    "Yu Mincho", "YuMincho", "Noto Serif JP",
    "Times New Roman", serif;
  font-size: 14px;
  line-height: 1.72;
  letter-spacing: 0;
}

a {
  color: inherit;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

a:focus-visible {
  outline: 2px solid currentColor;
  outline-offset: 3px;
}

.site-shell {
  width: min(calc(100% - 40px), 1180px);
  margin: 0 auto;
}

.site-header {
  padding: 18px 0 14px;
  border-bottom: 1px solid var(--rule);
}

.site-header-main {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  align-items: baseline;
}

.site-title {
  margin: 0;
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.04em;
}

.site-title a { text-decoration: none; }

.site-tagline {
  margin: 0;
  font-size: 11.5px;
  color: var(--muted);
  text-align: right;
}

.site-nav {
  display: flex;
  gap: 1.35em;
  margin-top: 9px;
  font-size: 11.5px;
  line-height: 1.5;
}

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

.site-nav a::before { content: "［"; }
.site-nav a::after { content: "］"; }

.site-nav a:hover {
  text-decoration: underline;
}

.index-main {
  padding: 28px 0 72px;
}

.index-heading {
  margin: 0 0 18px;
  font-size: 13px;
  font-weight: 400;
  letter-spacing: 0.08em;
}

.article-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 30px 22px;
}

.article-card {
  display: block;
  text-decoration: none;
}

.article-card-image,
.article-hero {
  width: 100%;
  aspect-ratio: 1232 / 648;
  display: block;
  object-fit: cover;
  object-position: center;
  background: var(--soft);
}

.article-card-title {
  margin: 9px 0 4px;
  font-size: 14.5px;
  line-height: 1.52;
  font-weight: 600;
}

.article-card-meta {
  margin: 0;
  color: var(--muted);
  font-size: 11.5px;
  line-height: 1.55;
}

.article-page {
  width: min(calc(100% - 40px), var(--content-width));
  margin: 0 auto;
  padding: 38px 0 90px;
}

.article-kicker {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 11.5px;
  letter-spacing: 0.06em;
}

.article-title {
  margin: 0 0 18px;
  font-size: clamp(24.5px, calc(3vw - 0.5px), 32.5px);
  line-height: 1.45;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.article-hero {
  margin: 0 0 20px;
}

.article-biblio {
  margin: 0 0 23px;
  padding: 10px 0;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
  display: grid;
  grid-template-columns: max-content 1fr max-content 1fr;
  column-gap: 10px;
  row-gap: 3px;
  font-size: 11.5px;
  line-height: 1.6;
  color: var(--muted);
}

.article-biblio dt,
.article-biblio dd { margin: 0; }

.article-biblio dt {
  color: #3e3e3e;
}

.article-lead {
  margin: 0 0 30px;
  font-size: 14.5px;
  line-height: 1.78;
}

.article-body h2 {
  margin: 2.35em 0 0.9em;
  padding: 0;
  font-size: 18.5px;
  line-height: 1.55;
  font-weight: 600;
  letter-spacing: 0.015em;
  scroll-margin-top: 1.5rem;
}

.article-body p {
  margin: 0 0 1em;
}

.article-body .question {
  margin: 1.45em 0 0.55em;
  font-weight: 600;
}

.article-body .editorial-note {
  margin: -0.15em 0 1.15em;
  font-size: 11px;
  line-height: 1.65;
  color: var(--muted);
}

.article-figure {
  margin: 1.55em 0 1.65em;
}

.article-figure img {
  display: block;
  width: 100%;
  height: auto;
}

.references {
  margin-top: 3em;
  padding-top: 1.2em;
  border-top: 1px solid var(--rule);
}

.references h2 {
  margin: 0 0 0.75em;
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.05em;
}

.references ol {
  margin: 0;
  padding-left: 1.8em;
  font-size: 11px;
  line-height: 1.7;
}

.references li { margin-bottom: 0.55em; }

.credit {
  margin-top: 2.5em !important;
  padding-top: 1.2em;
  border-top: 1px solid var(--rule);
  color: #333;
  font-size: 11.5px;
  line-height: 1.7;
}

.back-link {
  display: inline-block;
  margin-top: 28px;
  font-size: 12px;
  color: var(--muted);
}

.error-page p {
  margin: 0;
}

.about-page {
  max-width: 760px;
}

.about-title {
  margin: 0 0 30px;
  font-size: clamp(22.5px, calc(2.6vw - 0.5px), 27.5px);
  line-height: 1.45;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.about-section {
  margin: 0 0 2.15em;
}

.about-section h2 {
  margin: 0 0 0.65em;
  font-size: 18.5px;
  line-height: 1.55;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.about-section h2::before {
  content: "■ ";
  font-size: 0.72em;
}

.about-section p,
.about-section li {
  font-size: 13px;
  line-height: 1.65;
}

.about-section p {
  margin: 0;
}

.about-policy {
  margin: 0;
  padding: 0;
  list-style: none;
}

.about-policy li {
  padding-left: 1em;
  text-indent: -1em;
}

.about-policy li::before {
  content: "・";
}

@media (max-width: 860px) {
  .article-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 620px) {
  body {
    font-size: 13px;
    line-height: 1.65;
  }

  .site-shell,
  .article-page {
    width: min(calc(100% - 36px), var(--content-width));
  }

  .site-header-main {
    align-items: flex-start;
    flex-direction: column;
    gap: 3px;
  }

  .site-tagline { text-align: left; }

  .site-nav {
    margin-top: 10px;
    font-size: 11px;
  }

  .index-main {
    padding-top: 22px;
  }

  .article-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .article-page {
    padding-top: 24px;
  }

  .article-kicker {
    margin-bottom: 6px;
    font-size: 11px;
  }

  .article-title {
    font-size: 21.5px;
    line-height: 1.38;
    margin-bottom: 15px;
  }

  .article-hero {
    margin-bottom: 16px;
  }

  .article-biblio {
    grid-template-columns: max-content 1fr;
    font-size: 11px;
    margin-bottom: 18px;
    padding: 8px 0;
  }

  .article-lead {
    font-size: 13px;
    line-height: 1.68;
    margin-bottom: 23px;
  }

  .article-body p {
    margin-bottom: 0.9em;
  }

  .article-body .question {
    margin-top: 1.3em;
    margin-bottom: 0.45em;
  }

  .article-body h2 {
    font-size: 15.5px;
    line-height: 1.5;
    margin-top: 1.7em;
    margin-bottom: 0.75em;
  }

  .article-figure {
    margin: 1.3em 0 1.4em;
  }

  .about-title {
    margin-bottom: 25px;
    font-size: 21.5px;
    line-height: 1.38;
  }

  .about-section {
    margin-bottom: 1.9em;
  }

  .about-section h2 {
    font-size: 15.5px;
    line-height: 1.5;
  }
}


/* v1.1: source notes and article information live at the end of the article. */
.references h2::before {
  content: "● ";
  font-size: 0.78em;
}

.article-biblio--footer {
  margin: 2.4em 0 0;
  padding: 1.2em 0 0;
  border-top: 1px solid var(--rule);
  border-bottom: 0;
  grid-template-columns: max-content 1fr;
  color: var(--ink);
  font-size: 12px;
  line-height: 1.7;
}

.article-biblio--footer dt {
  color: var(--ink);
}

@media (max-width: 620px) {
  .article-biblio--footer {
    font-size: 12px;
    margin-top: 2.2em;
    padding-top: 1em;
  }
}

.article-figure figcaption {
  margin: 0.62em auto 0;
  max-width: 92%;
  font-size: 12.5px;
  line-height: 1.65;
  text-align: center;
  color: #2f2f2f;
}

.article-figure--diagram img {
  object-fit: contain;
}

@media (max-width: 620px) {
  .article-figure figcaption {
    margin-top: 0.55em;
    max-width: 96%;
    font-size: 12px;
    line-height: 1.6;
  }
}