:root {
  --bg: #ffffff;
  --bg-soft: #f7f8fa;
  --line: #e3e7ed;
  --line-strong: #cfd6e0;
  --text: #1a2330;
  --muted: #5c6b7e;
  --muted-2: #8b97a6;
  --accent: #b3261e;      /* red — red-teaming, used sparingly */
  --link: #1257b0;
  --maxw: 900px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Noto Sans JP",
    "Yu Gothic", Meiryo, system-ui, -apple-system, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- Header ---------- */
.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--bg);
}
/* padding は上下のみ指定（左右は .wrap の padding を活かす。padding 短縮形だと左右が 0 に上書きされるため）*/
.nav { display: flex; align-items: center; gap: 12px 28px; min-height: 62px; padding-top: 10px; padding-bottom: 10px; flex-wrap: wrap; }
.brand { font-weight: 700; color: var(--text); letter-spacing: .01em; font-size: 15px; line-height: 1.45; }
.brand:hover { text-decoration: none; color: var(--accent); }
.brand-br { display: none; } /* 狭い画面でのみブランド名を2行に折る（mobileで有効化） */
.nav .spacer { flex: 1; }
.nav-links { display: flex; align-items: center; gap: 22px; flex-shrink: 0; }
.nav-links a { color: var(--muted); font-size: 15px; }
.nav-links a:hover { color: var(--text); text-decoration: none; }
.nav-links a.active { color: var(--text); font-weight: 700; }
/* 言語切替：ページタブとは役割が違うので見た目を差別化（小型ピル）。
   PC ではタブ列から切り離し、ページ（ビューポート）の一番右端に right で寄せて配置する */
.nav-links a.lang {
  font-size: 12.5px; line-height: 1.6; color: var(--muted-2);
  border: 1px solid var(--line-strong); border-radius: 999px; padding: 2px 11px;
}
.nav-links a.lang:hover { color: var(--text); border-color: var(--link); text-decoration: none; }
@media (min-width: 601px) {
  /* 本文コンテンツ（.wrap）右端に揃えて配置。right:24px は .wrap の左右パディングと同値で、
     下の本文の右端とピルの右端が一直線になる。タブ列は padding-right で退避して重なりを防ぐ */
  .wrap.nav { position: relative; padding-right: 120px; }
  .nav-links a.lang { position: absolute; right: 24px; top: 50%; transform: translateY(-50%); }
}
/* ハンバーガー（モバイルのみ表示。既定＝PCでは非表示） */
.nav-toggle { position: absolute; opacity: 0; width: 0; height: 0; }
.nav-burger { display: none; }

/* ---------- Page head ---------- */
.page-head { padding: 38px 0 6px; }
.kicker { font-size: 13px; font-weight: 700; letter-spacing: .12em; color: var(--accent); text-transform: uppercase; }
.head-row { display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.lang-switch {
  flex: none; font-size: 13px; color: var(--muted);
  border: 1px solid var(--line-strong); border-radius: 999px; padding: 4px 13px;
}
.lang-switch:hover { text-decoration: none; color: var(--text); border-color: var(--link); }
h1 { font-size: clamp(26px, 4vw, 34px); line-height: 1.4; margin: 12px 0 14px; }
.lead { font-size: 17px; color: var(--muted); margin: 0; max-width: 680px; }
.lead + .lead { margin-top: 14px; }

/* ---------- Sections ---------- */
section { padding: 26px 0; border-top: 1px solid var(--line); }
section:first-of-type { border-top: none; }
h2 { font-size: 22px; margin: 0 0 16px; }
h3 { font-size: 17px; margin: 0 0 6px; }
p { margin: 0 0 14px; }
p:last-child { margin-bottom: 0; }

/* ---------- Simple nav list (index) ---------- */
.links { list-style: none; padding: 0; margin: 0; }
.links li { border-top: 1px solid var(--line); }
.links li:last-child { border-bottom: 1px solid var(--line); }
.links a { display: block; padding: 18px 4px; color: var(--text); }
.links a:hover { text-decoration: none; background: var(--bg-soft); }
.links .t { font-weight: 700; font-size: 17px; }
.links .t::after { content: " →"; color: var(--accent); }
.links .d { color: var(--muted); font-size: 15px; }

/* ---------- Definition table ---------- */
.table-wrap { overflow-x: auto; }
table { border-collapse: collapse; width: 100%; font-size: 15px; }
th, td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--line); vertical-align: top; }
thead th { border-bottom: 2px solid var(--line-strong); font-weight: 700; white-space: nowrap; }
tbody th { font-weight: 700; white-space: nowrap; color: var(--text); background: var(--bg-soft); width: 30%; }
td { color: var(--muted); }
td strong { color: var(--text); }

/* ---------- Ordered flow ---------- */
ol.flow { margin: 0; padding-left: 20px; }
ol.flow li { margin-bottom: 10px; }
ol.flow li strong { color: var(--text); }

/* ---------- Roles / plain list ---------- */
.stack { display: grid; gap: 18px; }
.stack .item h3 { margin-bottom: 4px; }
.stack .item p { color: var(--muted); margin: 0; font-size: 15px; }

.namegrid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 4px 32px; }
.namegrid .person { padding: 12px 0; border-bottom: 1px solid var(--line); }
.namegrid .person .n { font-weight: 700; }
.namegrid .person .a { color: var(--muted); font-size: 14px; }

/* ---------- Inline method list ---------- */
.methods { columns: 2; column-gap: 32px; margin: 0; padding-left: 20px; }
.methods li { margin-bottom: 4px; }
@media (max-width: 560px) { .methods { columns: 1; } .namegrid { grid-template-columns: 1fr; } }

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--line); margin-top: 20px; padding: 26px 0 48px; color: var(--muted); font-size: 14px; }
.site-footer a { color: var(--muted); text-decoration: underline; }
.site-footer p { margin: 0 0 4px; }
.site-footer .copyright { margin-top: 12px; color: var(--muted-2); font-size: 13px; }
.site-footer .internal { float: right; color: #9aa6b4; font-size: 12px; text-decoration: none; opacity: .6; }
.site-footer .internal:hover { opacity: 1; text-decoration: underline; }

/* ---------- News page extras ---------- */
.news-more { margin-top: 12px; font-size: 14px; }
.news-more a::after { content: " \2192"; color: var(--accent); }
.callout {
  border: 1px solid var(--line); border-left: 3px solid var(--accent);
  border-radius: 8px; background: var(--bg-soft); padding: 14px 18px;
}
.callout .note { color: var(--muted-2); font-size: 13px; margin: 0; }
.goals { display: grid; gap: 14px; margin: 4px 0 0; padding: 0; list-style: none; counter-reset: g; }
.goals li { position: relative; padding: 2px 0 2px 44px; }
.goals li::before {
  counter-increment: g; content: counter(g);
  position: absolute; left: 0; top: 0;
  width: 30px; height: 30px; border-radius: 50%;
  background: var(--bg-soft); border: 1px solid var(--line-strong);
  color: var(--accent); font-weight: 700; font-size: 14px;
  display: grid; place-items: center;
}
.goals li .g-t { font-weight: 700; }
.goals li .g-d { color: var(--muted); font-size: 14px; }

/* ---------- Figure / diagram ---------- */
figure.diagram { margin: 0; }
figure.diagram svg { width: 100%; height: auto; display: block; border: 1px solid var(--line); border-radius: 8px; background: #fff; }
figure.diagram figcaption { color: var(--muted); font-size: 13px; margin-top: 10px; }

/* ---------- Abstract / home links ---------- */
.abstract { font-size: 16px; }
.home-links { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; margin-top: 4px; }
.home-links a { display: block; border: 1px solid var(--line); border-radius: 10px; padding: 16px 18px; color: var(--text); }
.home-links a:hover { text-decoration: none; border-color: var(--link); }
.home-links .t { font-weight: 700; }
.home-links .t::after { content: " \2192"; color: var(--accent); }
.home-links .d { color: var(--muted); font-size: 14px; margin-top: 2px; }
@media (max-width: 560px) { .home-links { grid-template-columns: 1fr; } }

/* ---------- News ---------- */
.news { border: 1px solid var(--line); border-radius: 10px; overflow: hidden; }
.news .news-item { display: flex; gap: 16px; padding: 14px 18px; border-top: 1px solid var(--line); }
.news .news-item:first-child { border-top: none; }
.news .news-item time { flex: none; color: var(--muted); font-variant-numeric: tabular-nums; font-size: 14px; width: 92px; }
.news .news-item .body { font-size: 15px; }
.news .news-item .body :first-child { margin-top: 0; }
.news .news-item .body :last-child { margin-bottom: 0; }
.news-empty { color: var(--muted); font-size: 14px; padding: 14px 18px; }

/* ---------- People / members ---------- */
.people { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
@media (max-width: 560px) { .people { grid-template-columns: 1fr; } }
.person { display: flex; gap: 16px; align-items: flex-start; }
.person .avatar {
  flex: none; width: 64px; height: 64px; border-radius: 8px;
  border: 1px solid var(--line-strong);
  background-color: var(--bg-soft);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%238b97a6'%3E%3Ccircle cx='12' cy='8.5' r='4'/%3E%3Cpath d='M4 20.5c0-4.4 3.6-6.8 8-6.8s8 2.4 8 6.8Z'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: center; background-size: 34px;
  display: grid; place-items: center; overflow: hidden;
}
.person .avatar img { width: 100%; height: 100%; object-fit: cover; }
.person .n { font-weight: 700; font-size: 16px; }
.person .n .en { color: var(--muted); font-weight: 400; font-size: 13px; margin-left: 6px; }
.person .r { color: var(--text); font-size: 14px; margin-top: 2px; }
.person .a { color: var(--muted); font-size: 13px; margin-top: 2px; }
.person .links { border: none; margin-top: 8px; display: flex; flex-wrap: wrap; gap: 8px; }
.person .links a {
  font-size: 12.5px; color: var(--link); text-decoration: none; line-height: 1.5;
  border: 1px solid var(--line-strong); border-radius: 999px; padding: 3px 12px;
}
.person .links a:hover { border-color: var(--link); background: var(--bg-soft); text-decoration: none; }
.person .links .sep { display: none; }
.subhead { font-size: 13px; font-weight: 700; letter-spacing: .02em; color: var(--muted-2); margin: 22px 0 12px; }
section > .subhead:first-of-type { margin-top: 6px; }

/* ---------- Publications ---------- */
.pub-year { font-weight: 700; font-size: 15px; color: var(--accent); margin: 20px 0 8px; }
.pub-cat {
  font-weight: 700; font-size: 15px; color: var(--accent);
  margin: 26px 0 8px; padding-bottom: 6px; border-bottom: 2px solid var(--line-strong);
}
.pub-cat:first-child { margin-top: 4px; }
.pub-list { list-style: none; margin: 0; padding: 0; }
.pub-list li { padding: 12px 0; border-top: 1px solid var(--line); font-size: 15px; }
.pub-list li:first-child { border-top: none; }
.pub-list .authors { color: var(--muted); }
.pub-list .title { font-weight: 700; }
.pub-list .venue { color: var(--muted); font-style: italic; }
.pub-list .badge {
  display: inline-block; font-size: 11.5px; font-weight: 700; line-height: 1.6;
  padding: 0 9px; border-radius: 999px; margin-left: 8px; white-space: nowrap; vertical-align: middle;
}
.pub-list .badge-rev { background: #e7f0e8; color: #2f6b34; border: 1px solid #cfe2d1; }
.pub-list .badge-rev-no { background: var(--bg-soft); color: var(--muted); border: 1px solid var(--line-strong); }

/* ---------- Responsive (mobile) ---------- */
@media (max-width: 600px) {
  body { font-size: 15.5px; line-height: 1.75; }
  .wrap { padding: 0 24px; }

  /* header: ブランド＋ハンバーガーを1行に、リンクは下に折りたたみ */
  .nav { flex-direction: row; flex-wrap: wrap; align-items: center; gap: 8px; min-height: 0; padding-top: 12px; padding-bottom: 12px; }
  .nav .spacer { display: none; }
  .brand { flex: 1 1 auto; font-size: 14px; line-height: 1.5; }
  .brand-br { display: inline; } /* 「〜に対する」の後で改行 */

  .nav-burger {
    display: inline-flex; align-items: center; justify-content: center;
    flex: none; width: 42px; height: 42px; margin-right: -8px;
    font-size: 22px; line-height: 1; color: var(--text); cursor: pointer;
    border-radius: 8px; -webkit-tap-highlight-color: transparent;
  }
  .nav-burger::before { content: "\2630"; }            /* ☰ */
  .nav-burger:active { background: var(--bg-soft); }
  .nav-toggle:checked ~ .nav-burger::before { content: "\2715"; font-size: 20px; } /* ✕ */

  .nav-links {
    display: none; order: 3; flex-basis: 100%; width: 100%;
    flex-direction: column; gap: 0; margin: 6px 0 2px;
    border-top: 1px solid var(--line);
  }
  .nav-toggle:checked ~ .nav-links { display: flex; }
  .nav-links a { padding: 13px 2px; font-size: 15px; color: var(--text); border-bottom: 1px solid var(--line); }
  .nav-links a:last-child { border-bottom: none; }
  .nav-links a.active { font-weight: 700; color: var(--accent); }
  /* 言語切替：開いたメニュー内ではタブと区別した小さなピルを中央に置く */
  .nav-links a.lang {
    align-self: center; margin: 10px 0 2px; padding: 3px 12px;
    font-size: 13px; color: var(--muted); border-bottom: none;
    border: 1px solid var(--line-strong); border-radius: 999px;
  }

  .page-head { padding: 30px 0 4px; }
  .head-row { flex-wrap: wrap; gap: 8px; }
  h1 { font-size: 22px; }
  .lead { font-size: 15.5px; }
  .lead + .lead { margin-top: 12px; }

  section { padding: 24px 0; }
  h2 { font-size: 19px; }

  /* single-column grids on phones */
  .home-links, .people, .namegrid { grid-template-columns: 1fr; }
  .methods { columns: 1; }

  /* tables: tighter cells, header column not forced wide */
  th, td { padding: 10px 12px; }
  tbody th { width: auto; white-space: normal; }

  /* smaller member avatars */
  .person { gap: 13px; }
  .person .avatar { width: 52px; height: 52px; font-size: 17px; }
  .person.featured { margin-bottom: 18px; }

  /* news rows: stack date above text */
  .news .news-item { flex-direction: column; gap: 4px; padding: 13px 15px; }
  .news .news-item time { width: auto; }

  /* footer: internal link on its own line */
  .site-footer { padding: 22px 0 40px; }
  .site-footer .internal { float: none; display: inline-block; margin-top: 12px; }
}