/* 2026年度 多変数関数論冬セミナー */

:root {
  color-scheme: only light;
  --ink: #262626;
  --muted: #666666;
  --accent: #28616a;
  --paper: #ffffff;
  --line: #e2e2e2;
  --nav: #ffffff;
  --width: 58rem;
  --gutter: clamp(1.25rem, 5vw, 3rem);
  --sans: "Hiragino Sans", "Hiragino Kaku Gothic ProN",
          "Yu Gothic", Meiryo, system-ui, sans-serif;
}

* { box-sizing: border-box; }

html {
  background: #ffffff;
  scroll-behavior: smooth;
  scroll-padding-top: 5rem;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  font-weight: 500;
  line-height: 1.9;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
}

::selection {
  background: color-mix(in srgb, var(--accent) 20%, transparent);
}

a {
  color: var(--accent);
  text-decoration-color: color-mix(in srgb, var(--accent) 40%, transparent);
  text-decoration-thickness: 1px;
  text-underline-offset: .25em;
}

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

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

.page-header,
.site-nav ul,
.main-content,
.site-footer {
  width: min(var(--width), calc(100% - var(--gutter) * 2));
  margin-inline: auto;
}

/* 年度を小さく、集会名を大きく。本文と左端を揃える。 */
.page-header {
  padding-block: clamp(3.5rem, 8vw, 6rem) 2.75rem;
}

.site-title {
  margin: 0;
  font-family: var(--sans);
  font-size: clamp(1.7rem, 4.4vw, 2.85rem);
  font-weight: 700;
  letter-spacing: .035em;
  line-height: 1.6;
  line-break: strict;
}

.title-year {
  display: block;
  margin-bottom: 1rem;
  color: var(--accent);
  font-family: var(--sans);
  font-size: .85rem;
  font-weight: 500;
  letter-spacing: .14em;
}

.title-name { text-wrap: balance; }

.header-meta {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem 1.8rem;
  margin: 1.5rem 0 0;
  color: var(--muted);
  font-size: .875rem;
  font-variant-numeric: tabular-nums;
}

/* 小さい画面ではメニュー全体を折り返して表示する。 */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--nav);
  border-block: 1px solid var(--line);
}

.site-nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 0 clamp(1rem, 3vw, 2rem);
  padding: 0;
  list-style: none;
}

.site-nav li { margin: 0; }

.site-nav a {
  display: block;
  padding: .85rem 0;
  color: var(--muted);
  font-size: .8rem;
  letter-spacing: .04em;
  text-decoration: none;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: .4em;
}

/* 見出しと本文を二列で揃えた、簡潔な組版。 */
.main-content {
  padding-block: 1.25rem 4rem;
}

.main-content section {
  display: grid;
  grid-template-columns: 9rem minmax(0, 1fr);
  column-gap: 2.5rem;
  padding-block: 2.3rem;
  border-bottom: 1px solid var(--line);
}

.main-content section > * { grid-column: 2; }
.main-content section > h2 { grid-column: 1; grid-row: 1; }
.main-content section > h2 + * { grid-row: 1; }
.main-content section > :last-child { margin-bottom: 0; }

h2 {
  margin: .1rem 0 0;
  font-family: var(--sans);
  font-size: 1.16rem;
  font-weight: 700;
  letter-spacing: .06em;
  line-height: 1.6;
}

h3 {
  margin: 1.5rem 0 .6rem;
  color: var(--accent);
  font-size: 1rem;
  font-weight: 500;
}

p { margin: 0 0 1rem; }
ul, ol { margin: 0 0 1rem; padding-left: 1.35rem; }
li { margin-bottom: .35rem; }
li::marker { color: var(--muted); }
.note { color: var(--muted); font-size: .875rem; }

.info-card dl {
  display: grid;
  grid-template-columns: 2.5rem minmax(0, 1fr);
  gap: 1.1rem 1.5rem;
  margin: 0;
}

.info-card dt {
  padding-top: .15rem;
  color: var(--muted);
  font-size: .8rem;
  letter-spacing: .08em;
}

.info-card dd { margin: 0; }

/* 講演情報が確定した後も同じ紙面で表示する。 */
.schedule-day { margin-bottom: 1.75rem; }
.schedule-day h3 { margin-top: 0; }
.talks { margin: 0; padding: 0; list-style: none; }
.talks li { margin: 0; padding-block: .75rem; border-bottom: 1px solid var(--line); }
.talks li:last-child { border-bottom: 0; }

.talk-time {
  display: inline-block;
  min-width: 7.5rem;
  color: var(--muted);
  font-size: .875rem;
  font-variant-numeric: tabular-nums;
}

.talk-speaker { font-weight: 600; }
.talk-title { display: block; color: var(--muted); font-size: .94rem; }

.organizers { margin: 0; padding: 0; list-style: none; }
.organizers li { margin: 0; padding-bottom: .6rem; }
.organizers + .note { margin-top: 1.1rem; }
a[href^="mailto:"] { overflow-wrap: anywhere; }

#grant p,
#grant li { font-size: .875rem; }
#grant ul { padding-left: 1.1rem; }

.site-footer {
  padding-block: 0 2.5rem;
  color: var(--muted);
  font-size: .75rem;
  letter-spacing: .04em;
}

.site-footer p { margin: 0; }

@media (max-width: 640px) {
  html { scroll-padding-top: 8rem; }
  .page-header { padding-bottom: 2rem; }
  .header-meta { display: grid; gap: .35rem; font-size: .8rem; }
  .site-nav a { padding-block: .55rem; }
  .main-content { padding-block: .5rem 2.5rem; }
  .main-content section { display: block; padding-block: 1.75rem; }
  h2 { margin: 0 0 1.1rem; }
  .main-content section > h2:last-child { margin: 0; }
  .info-card dl { gap: .9rem 1rem; }
  .talk-time { display: block; min-width: 0; }
}

@media (max-width: 380px) {
  .info-card dl { grid-template-columns: 1fr; gap: .2rem; }
  .info-card dd + dt { margin-top: .65rem; }
}

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

@media print {
  :root {
    color-scheme: light;
    --ink: #000;
    --muted: #333;
    --accent: #000;
    --paper: #fff;
    --line: #ccc;
  }
  .page-header { padding-block: 1rem 2rem; }
  .site-nav { display: none; }
  .main-content { padding-block: 0 2rem; }
  .main-content section { break-inside: avoid; }
  h2, h3 { break-after: avoid; }
}