:root {
  --ground: #F8F3E4;
  --ink:    #2B2C2E;
  --ink-2:  #43444A;
  --ink-3:  #6D6A63;
  --ink-4:  #97938B;
  --c-blue:   #3E76B4;
  --c-red:    #CE5335;
  --c-green:  #5F7F40;
  --c-yellow: #D08A38;
  --link:     #3A6EA7;
  --border-faint: rgba(43, 44, 46, .14);
  --subj-instanton:      #2F5A85;
  --subj-monopole:       #4C6733;
  --subj-localization:   #8A5518;
  --subj-discretization: #A53D2A;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ground: #1A1A1C;
    --ink:    #ECE7DC;
    --ink-2:  #C6C1B6;
    --ink-3:  #B9B4A9;
    --ink-4:  #85817A;
    --c-blue:   #74A1D4;
    --c-red:    #D0544A;
    --c-green:  #A2BD66;
    --c-yellow: #E3BF5A;
    --link:     #74A1D4;
    --border-faint: rgba(236, 231, 220, .16);
    --subj-instanton:      #74A1D4;
    --subj-monopole:       #A2BD66;
    --subj-localization:   #E3BF5A;
    --subj-discretization: #E0685E;
  }
}

html[data-theme="dark"] {
  --ground: #1A1A1C;
  --ink:    #ECE7DC;
  --ink-2:  #C6C1B6;
  --ink-3:  #B9B4A9;
  --ink-4:  #85817A;
  --c-blue:   #74A1D4;
  --c-red:    #D0544A;
  --c-green:  #A2BD66;
  --c-yellow: #E3BF5A;
  --link:     #74A1D4;
  --border-faint: rgba(236, 231, 220, .16);
  --subj-instanton:      #74A1D4;
  --subj-monopole:       #A2BD66;
  --subj-localization:   #E3BF5A;
  --subj-discretization: #E0685E;
}

:root {
  --serif: 'Libre Caslon Text', 'Zen Old Mincho', 'Hiragino Mincho ProN', serif;
  --sans:  'Zen Kaku Gothic New', 'Hiragino Kaku Gothic ProN', sans-serif;
  --sans-latin: 'Mulish', 'Zen Kaku Gothic New', 'Hiragino Kaku Gothic ProN', sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-family: var(--serif);
  font-size: 16px;
  line-height: 1.9;
  color: var(--ink-2);
  background: var(--ground);
}

h1, h2, h3 {
  font-family: var(--serif);
  font-weight: 500;
  color: var(--ink);
}

nav, .ui { font-family: var(--sans); }

.katex { font-size: 1.06em; }

a {
  color: var(--link);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: .2em;
}
a:hover { text-decoration-thickness: 2px; }

a.subj-instanton      { color: var(--subj-instanton); }
a.subj-monopole       { color: var(--subj-monopole); }
a.subj-localization   { color: var(--subj-localization); }
a.subj-discretization { color: var(--subj-discretization); }

.container {
  width: 100%;
  max-width: 46rem;
  margin-inline: auto;
  padding-inline: 1.5rem;
}

main.container {
  flex: 1;
  padding-block: 2rem 4rem;
}

.site-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  width: 100%;
  max-width: 46rem;
  margin-inline: auto;
  padding: 1.1rem 1.5rem .9rem;
  font-size: .82rem;
  letter-spacing: .08em;
}
.site-header a { text-decoration: none; }
.site-header .brand { color: var(--ink-3); font-weight: 500; }
.site-header nav { display: flex; gap: 1.5em; }
.site-header nav a { color: var(--ink-4); }
.site-header nav a[aria-current="page"] { color: var(--ink); }
.site-header a:hover { color: var(--ink); }

.strokes { display: flex; gap: 6px; }
.stroke { width: 18px; height: 5px; border-radius: 2px; }
.stroke.c-blue   { background: var(--c-blue); }
.stroke.c-red    { background: var(--c-red); }
.stroke.c-green  { background: var(--c-green); }
.stroke.c-yellow { background: var(--c-yellow); }

.hero { text-align: center; padding-top: 4rem; }
.hero .strokes { justify-content: center; margin-bottom: 1.9rem; }

.hero-kicker {
  color: var(--ink-3);
  font-size: .92rem;
  letter-spacing: .14em;
  margin: 0 0 1.3em;
}
.site-title {
  font-size: clamp(28px, 6vw, 44px);
  letter-spacing: .1em;
  margin: 0 0 .9em;
}
.site-title-en {
  font-style: italic;
  color: var(--ink-3);
  font-size: 1.05rem;
  margin: 0 0 2.4em;
}

.hero-meta { margin: 0; font-size: 1.02rem; }
.meta-line { margin: .25em 0; color: var(--ink); }
.meta-label {
  font-family: var(--sans);
  font-size: .72em;
  letter-spacing: .22em;
  color: var(--ink-3);
  margin-right: 1em;
}

.portrait { margin: 4rem 0 0; text-align: center; }
.portrait img { width: 24rem; max-width: 100%; height: auto; }
.portrait figcaption {
  font-family: var(--sans);
  font-size: .72rem;
  letter-spacing: .04em;
  color: var(--ink-4);
  margin-top: .7rem;
}

.lead { margin-top: 3.3rem; }
.lead p {
  margin: 0 0 1.1em;
  text-align: justify;
  text-wrap: pretty;
}

.placeholder { color: var(--ink-3); }

.page-header { margin: 1.5rem 0 1.6rem; }
.page-title { font-size: 1.7rem; letter-spacing: .08em; margin: 0; }

.pub-nav { display: flex; flex-wrap: wrap; gap: .4em 1.6em; font-size: .85rem; margin: 0 0 2.2rem; }
.pub-nav a { text-decoration: none; }
.pub-nav a:hover { text-decoration: underline; text-underline-offset: .2em; }

.pub-section { scroll-margin-top: 1.2rem; }
.pub-section h2 {
  font-size: 1.35rem;
  letter-spacing: .07em;
  margin: 3.2rem 0 1.3rem;
  padding-bottom: .45rem;
  border-bottom: 1px solid var(--border-faint);
}
ol.bibliography { list-style: none; margin: 0; padding: 0; }
ol.bibliography > li { padding: 1.05rem 0; border-top: 1px solid var(--border-faint); }
ol.bibliography > li:first-child { border-top: none; padding-top: .2rem; }

.bib-title {
  font-family: var(--sans);
  font-weight: 700;
  font-size: 1.02rem;
  line-height: 1.6;
  color: var(--ink);
  margin: 0 0 .3rem;
  scroll-margin-top: 1.5rem;
}
.bib-authors {
  font-family: var(--sans-latin);
  font-size: .85rem;
  color: var(--ink-2);
  margin: 0 0 .25rem;
}
.bib-meta {
  display: flex;
  flex-wrap: wrap;
  gap: .1rem .7rem;
  font-family: var(--sans-latin);
  font-size: .82rem;
  color: var(--ink-3);
  margin: 0 0 .55rem;
}
.bib-journal { font-style: italic; font-synthesis: none; }
.bib-journal--ja { font-style: normal; }
.bib-note {
  font-family: var(--sans-latin);
  font-size: .78rem;
  color: var(--ink-3);
  margin: -.35rem 0 .55rem;
}
.bib-links {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem .5rem;
}
.bib-links a {
  font-family: var(--sans-latin);
  font-size: .72rem;
  letter-spacing: .03em;
  text-decoration: none;
  border: 1px solid color-mix(in srgb, var(--c-blue) 40%, transparent);
  border-radius: 999px;
  padding: 2px 10px;
}
.bib-links a:hover { border-color: var(--c-blue); }

/* フッターは常に黒板（モード非依存） */
.site-footer {
  --ground: #1A1A1C;
  --ink:    #ECE7DC;
  --ink-2:  #C6C1B6;
  --ink-3:  #B9B4A9;
  --ink-4:  #85817A;
  --c-blue:   #74A1D4;
  --c-red:    #D0544A;
  --c-green:  #A2BD66;
  --c-yellow: #E3BF5A;
  background: var(--ground);
  color: var(--ink-2);
  border-top: 1px solid rgba(236, 231, 220, .12);
  padding: 2.8rem 0 2.4rem;
  text-align: center;
}
.site-footer .strokes { justify-content: center; margin-bottom: 1.7rem; }
.footer-math { color: var(--ink); margin: 0 0 1.5rem; }
.footer-math a { color: inherit; text-decoration: none; }
.footer-math a:hover { text-decoration: underline; text-underline-offset: .3em; text-decoration-thickness: 1px; }
.footer-meta {
  font-family: var(--sans);
  font-size: .8rem;
  letter-spacing: .05em;
  color: var(--ink-4);
  margin: .35em 0 0;
}