/* 色と幅はここでまとめて変更できます。アクセントは青1色。 */
:root {
  color-scheme: light;
  --background: #fafafa;
  --surface: #f1f3f5;
  --text: #17191c;
  --muted: #606873;
  --accent: #264d73;
  --line: #dfe3e8;
  --content-width: 920px;
  /* HOME：ヘッダー下の線から画像までの余白。小さくすると画像が上に寄ります。 */
  --home-image-gap: 40px;
  --home-image-gap-mobile: 28px;
}

* { box-sizing: border-box; }
html { scroll-padding-top: 24px; }
body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
  font-size: 1rem;
  line-height: 1.9;
  overflow-wrap: anywhere;
}
a { color: var(--accent); text-underline-offset: .25em; }
a:hover { text-decoration-thickness: 2px; }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 5px; border-radius: 2px; }
img { display: block; max-width: 100%; height: auto; }
h1, h2, h3, p, figure { margin: 0; }
.site-shell { width: min(var(--content-width), calc(100% - 64px)); margin-inline: auto; }
.skip-link { position: absolute; top: 8px; left: 16px; padding: 8px 16px; background: white; transform: translateY(-160%); z-index: 10; }
.skip-link:focus { transform: translateY(0); }
.site-header { display: flex; justify-content: space-between; align-items: center; gap: 24px; padding-block: 30px; border-bottom: 1px solid var(--line); }
.wordmark { color: var(--text); font-size: 1.1rem; font-weight: 700; letter-spacing: .08em; text-decoration: none; line-height: 1.45; }
.wordmark span { display: block; margin-top: 4px; color: var(--muted); font-size: .875rem; font-weight: 400; letter-spacing: .1em; }
nav { display: flex; flex-wrap: wrap; gap: 8px 24px; }
nav a { padding-block: 7px; color: var(--text); font-size: .875rem; text-decoration: none; }
nav a:hover { color: var(--accent); text-decoration: underline; }
.introduction { padding-block: 64px 36px; border-bottom: 1px solid var(--line); }
.eyebrow { color: var(--accent); font-size: .75rem; letter-spacing: .12em; font-weight: 600; }
h1 { margin-block: 14px 18px; font-size: clamp(1.75rem, 4vw, 2.35rem); font-weight: 600; line-height: 1.45; letter-spacing: .02em; }
h1 span { font-size: .7em; font-weight: 400; }
.introduction > p:not(.eyebrow) { color: var(--muted); }
.intro-contact { display: flex; flex-wrap: wrap; align-items: baseline; gap: 6px 20px; margin-top: 20px; }
.contact-label { color: var(--accent); font-size: .875rem; font-weight: 600; }
.intro-news { margin-top: 28px; }
.intro-news > h2 { margin-bottom: 10px; color: var(--accent); font-size: .875rem; letter-spacing: .08em; }
.news-scroll { height: 8rem; overflow-y: scroll; overflow-x: hidden; padding: 12px 16px; background: var(--surface); scrollbar-gutter: stable; scrollbar-width: thin; scrollbar-color: #a8b4bf #e3e7ec; }
.news-scroll:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }
.news-list { margin: 0; padding: 0; list-style: none; }
.news-empty { color: var(--muted); font-size: .875rem; }
.news-entry { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 18px; font-size: .875rem; }
.news-entry + .news-entry { margin-top: 12px; padding-top: 12px; border-top: 1px solid var(--line); }
.news-entry time { flex: 0 0 auto; color: var(--muted); font-variant-numeric: tabular-nums; }
.news-entry p { flex: 1 1 16rem; }
.content-section { padding-block: 38px 44px; border-bottom: 1px solid var(--line); }
.illustration-section { padding-top: 12px; }
.section-heading { display: flex; flex-wrap: wrap; align-items: baseline; gap: 10px 18px; margin-bottom: 24px; }
h2 { font-size: 1.25rem; line-height: 1.5; font-weight: 600; letter-spacing: .02em; }
.section-heading > span { color: var(--muted); font-size: .875rem; }
.illustration img { width: 100%; background: var(--surface); border: 1px solid var(--line); }
figcaption { margin-top: 10px; color: var(--muted); font-size: .875rem; text-align: right; }
.video-entry { display: grid; grid-template-columns: minmax(0, 360px) minmax(0, 1fr); align-items: center; gap: 32px; }
.content-disclosure > summary { display: flex; flex-wrap: wrap; align-items: baseline; gap: 10px 18px; cursor: pointer; list-style: none; padding-block: 6px; }
.content-disclosure > summary::-webkit-details-marker { display: none; }
.content-disclosure > summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 5px; }
.content-disclosure > summary:hover h2 { color: var(--accent); }
.disclosure-subtitle { color: var(--muted); font-size: .875rem; }
.disclosure-action { display: flex; align-items: center; gap: 12px; margin-left: auto; color: var(--accent); font-size: .875rem; }
.disclosure-action::after { content: "+"; font-size: 1.25rem; line-height: 1; }
.content-disclosure[open] .disclosure-action::after { content: "−"; }
.when-open, .content-disclosure[open] .when-closed { display: none; }
.content-disclosure[open] .when-open { display: inline; }
.disclosure-content { margin-top: 24px; }
.video-thumbnail { display: block; border: 1px solid var(--line); background: var(--surface); }
.video-thumbnail img { width: 100%; aspect-ratio: 16 / 9; object-fit: cover; }
.entry-label { margin-bottom: 8px; color: var(--accent); font-size: .75rem; font-weight: 600; letter-spacing: .1em; }
h3 { font-size: 1.2rem; font-weight: 600; line-height: 1.65; }
.paper-entry h3 { font-size: 1.05rem; }
.video-information > p:not(.entry-label) { margin-block: 10px 16px; color: var(--muted); }
.text-link, .pending-link { font-size: .875rem; }
.pending-link { color: var(--muted); }
.pending-link > span { font-size: .8125rem; }
.paper-authors { margin-bottom: 8px; }
.paper-year { color: var(--muted); font-size: .875rem; }
.paper-meta { display: flex; flex-wrap: wrap; align-items: baseline; gap: 8px 24px; margin-top: 12px; }
.paper-meta .paper-links { margin-top: 0; }
.paper-abstract { margin-top: 18px; padding-left: 16px; border-left: 2px solid var(--line); color: var(--muted); font-size: .875rem; line-height: 1.85; }
.abstract-label { font-weight: 600; }
.paper-abstract > summary { display: inline-flex; align-items: center; gap: 12px; cursor: pointer; list-style: none; padding-block: 4px; }
.paper-abstract > summary::-webkit-details-marker { display: none; }
.paper-abstract > summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }
.abstract-toggle::after { content: "+"; }
.paper-abstract[open] .abstract-toggle::after { content: "−"; }
.abstract-text { margin-top: 8px; }
.paper-abstract mjx-container { max-width: 100%; overflow-x: auto; overflow-y: hidden; }
mjx-container[display="true"] { max-width: 100%; overflow-x: auto; overflow-y: hidden; }
.paper-links { display: flex; flex-wrap: wrap; gap: 12px 28px; margin-top: 18px; }
/* 2本目以降の論文・動画を追加した場合の区切り */
.paper-entry + .paper-entry, .video-entry + .video-entry { margin-top: 32px; padding-top: 32px; border-top: 1px solid var(--line); }
.site-footer { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 16px; padding-block: 24px 40px; color: var(--muted); }
.site-footer small, .site-footer a { font-size: .8125rem; }
.site-footer a { color: var(--muted); }

@media (max-width: 640px) {
  .site-shell { width: calc(100% - 40px); }
  .site-header { align-items: flex-start; flex-direction: column; gap: 16px; padding-block: 24px 18px; }
  nav { gap: 8px 20px; }
  .introduction { padding-block: 38px 28px; }
  .eyebrow { max-width: 28em; line-height: 1.8; }
  h1 span { display: block; margin-top: 4px; }
  .content-section { padding-block: 28px 32px; }
  .illustration-section { padding-top: 8px; }
  .section-heading { margin-bottom: 18px; }
  .video-entry { grid-template-columns: minmax(0, 1fr); gap: 20px; }
  .site-footer { padding-bottom: 28px; }
}

@media print {
  body { background: white; }
  .site-shell { width: 100%; }
  .skip-link, nav, .site-footer > a { display: none; }
  .introduction { padding-top: 24px; }
  .video-entry, .paper-entry, figure { break-inside: avoid; }
}

.video-thumbnail img { object-fit: contain; }

/* キービジュアルと動画サムネイルを同じ枠内で切り替えます。 */
.key-slideshow { margin-bottom: 24px; }
.slide-stage { position: relative; aspect-ratio: 16 / 9; background: var(--surface); }
.slide-stage img { width: 100%; height: 100%; object-fit: contain; }
.key-slideshow figcaption { text-align: left; min-height: 1.9em; }
.slide-navigation[hidden] { display: none; }
.slide-arrow { position: absolute; top: 50%; transform: translateY(-50%); display: grid; place-items: center; width: 44px; height: 44px; padding: 0; border: 0; border-radius: 50%; background: transparent; opacity: 0; pointer-events: none; cursor: pointer; }
.slide-stage .slide-arrow-icon { width: 100%; height: 100%; border: 0; background: transparent; filter: brightness(0) invert(1); object-fit: contain; }
.slide-previous { left: 12px; }
.slide-next { right: 12px; }
.slide-stage:hover .slide-arrow { opacity: .65; pointer-events: auto; }
.slide-stage .slide-arrow:hover { opacity: .85; }
.slide-stage .slide-arrow:focus-visible { outline: 2px solid white; outline-offset: 3px; opacity: .85; pointer-events: auto; }
@media (hover: none), (pointer: coarse), (max-width: 640px) { .slide-navigation { display: none; } }
@media print { .slide-navigation { display: none; } }

/* HOMEの画像上の余白だけ調整。画像・本文・NEWSは共通デザインの大きさを使います。 */
.home-page .introduction { padding-top: var(--home-image-gap); }
@media (max-width: 640px) {
  .home-page .introduction { padding-top: var(--home-image-gap-mobile); }
}

.slide-stage > img { touch-action: manipulation; user-select: none; -webkit-user-drag: none; }