:root {
  --navy: #0b2748;
  --text: #23364c;
  --muted: #647387;
  --line: #d7dfe8;
  --paper: #ffffff;
  --soft: #f6f8fa;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--text);
  font-family: Arial, "Yu Gothic", Meiryo, sans-serif;
  font-size: 16px;
  line-height: 1.85;
}

a {
  color: var(--navy);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.22em;
}

a:hover {
  text-decoration-style: dashed;
}

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

h1,
h2,
h3,
h4,
p,
dl,
dd {
  margin-top: 0;
}

h1,
h2,
h3,
h4 {
  color: var(--navy);
  font-family: inherit;
  font-weight: 600;
}

.container,
.header-inner {
  width: min(calc(100% - 96px), 1104px);
  margin-right: auto;
  margin-left: auto;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 10;
  padding: 8px 12px;
  border: 1px solid var(--navy);
  background: var(--paper);
  transform: translateY(-180%);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--paper);
}

.header-inner {
  display: flex;
  min-height: 80px;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
}

.site-name {
  display: flex;
  color: var(--navy);
  line-height: 1.25;
  text-decoration: none;
  flex-direction: column;
}

.site-name strong {
  font-family: inherit;
  font-size: 0.96rem;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  white-space: nowrap;
}

nav {
  display: flex;
  gap: 28px;
}

nav a {
  color: var(--text);
  font-size: 0.9rem;
  letter-spacing: 0.06em;
  text-decoration: none;
  white-space: nowrap;
}

nav a:hover,
nav a[aria-current="page"] {
  text-decoration: underline;
  text-underline-offset: 0.35em;
}

.language-switch {
  flex: 0 0 auto;
  font-size: 0.82rem;
  white-space: nowrap;
}

.language-switch [aria-current="true"] {
  color: var(--navy);
  font-weight: 700;
}

.intro {
  padding: 80px 0 86px;
  border-bottom: 1px solid var(--line);
}

.intro h1 {
  margin-bottom: 8px;
  font-size: clamp(1.65rem, 5vw, 2.15rem);
  line-height: 1.25;
}

.role {
  margin-bottom: 2px;
  color: var(--navy);
  font-size: 0.95rem;
  font-weight: 600;
}

.lab {
  margin-bottom: 28px;
  color: var(--navy);
  font-size: 0.95rem;
  font-weight: 600;
}

.lead {
  max-width: 700px;
  margin-bottom: 24px;
  color: var(--text);
  font-size: 1rem;
  line-height: 1.9;
}

.section {
  padding: 72px 0;
  border-bottom: 1px solid var(--line);
}

.section-layout {
  display: grid;
  grid-template-columns: 190px minmax(0, 1fr);
  gap: 64px;
}

.section-heading h2,
.papers-heading h2 {
  margin-bottom: 0;
  font-size: 1.75rem;
  line-height: 1.4;
}

.section-body > :last-child {
  margin-bottom: 0;
}

.section-body h3 {
  margin-bottom: 12px;
  font-size: 1.18rem;
}

.facts {
  margin-top: 30px;
  border-top: 1px solid var(--line);
}

.section-body > .facts:first-child {
  margin-top: 0;
}

.facts div {
  display: grid;
  grid-template-columns: 110px minmax(0, 1fr);
  gap: 20px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.facts dt {
  color: #000000;
  font-size: 0.9rem;
  font-weight: 700;
}

.facts dd {
  margin-bottom: 0;
}

.facts.compact {
  margin-top: 26px;
}

.history-list,
.award-list {
  padding: 0;
  margin: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.history-list li {
  display: grid;
  grid-template-columns: 110px minmax(0, 1fr);
  gap: 24px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}

.history-list time,
.award-list time {
  color: var(--muted);
  font-size: 0.82rem;
  white-space: nowrap;
}

.publication-list time {
  font-size: 0.95rem;
  font-weight: 600;
}

.career-page .history-list time {
  color: #000000;
}

.career-page .history-list li {
  grid-template-columns: 170px minmax(0, 1fr);
}

.history-list h3 {
  margin-bottom: 4px;
  font-size: 1rem;
}

.history-list p {
  margin-bottom: 0;
  font-size: 0.9rem;
}

.section-link {
  margin-top: 22px;
  margin-bottom: 6px;
}

.entry-list {
  padding: 0;
  margin: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.entry-list li {
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.activity-groups {
  display: grid;
  gap: 34px;
}

.activity-group h3 {
  margin-bottom: 10px;
  font-size: 0.95rem;
}

.social-link {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
}

.news-list {
  padding-left: 1.4rem;
  margin: 0;
}

.news-list li {
  padding: 6px 0;
}

.news-list time {
  margin-right: 1.5rem;
  white-space: nowrap;
}

.award-list li {
  display: grid;
  grid-template-columns: 100px minmax(0, 1fr);
  gap: 24px;
  padding: 17px 0;
  border-bottom: 1px solid var(--line);
}

.contact {
  background: var(--soft);
}

.email {
  margin-top: 24px;
  font-size: 1.05rem;
}

.note {
  color: var(--muted);
  font-size: 0.78rem;
}

.site-footer {
  padding: 32px 0;
  color: var(--muted);
  font-size: 0.75rem;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 24px;
}

.footer-inner p {
  margin-bottom: 0;
}

.research-intro {
  padding-top: 68px;
  padding-bottom: 68px;
}

.research-intro h1 {
  font-size: clamp(2.2rem, 6vw, 3.4rem);
}

.theme-list {
  border-top: 1px solid var(--line);
}

.theme-list div {
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}

.theme-list dt {
  margin-bottom: 6px;
  color: var(--navy);
  font-family: inherit;
  font-size: 1.05rem;
  font-weight: 600;
}

.theme-list dd {
  margin-bottom: 0;
}

.papers-heading {
  padding-bottom: 30px;
}

.papers-heading .note {
  margin-top: 16px;
  margin-bottom: 0;
}

.paper {
  padding: 38px 0 42px;
  border-top: 1px solid var(--line);
}

.paper-meta,
.citation {
  color: var(--muted);
  font-size: 0.78rem;
}

.paper h3 {
  max-width: 760px;
  margin-bottom: 10px;
  font-size: 1.4rem;
  line-height: 1.55;
}

.paper h4 {
  margin-top: 28px;
  margin-bottom: 8px;
  font-family: inherit;
  font-size: 0.78rem;
  font-weight: 700;
}

.paper > p:not(.paper-meta):not(.citation) {
  max-width: 760px;
}

@media (max-width: 700px) {
  .container,
  .header-inner {
    width: min(calc(100% - 32px), 1104px);
    margin-right: auto;
    margin-left: auto;
  }

  .header-inner {
    min-height: 72px;
    gap: 18px;
  }

  nav {
    gap: 14px;
  }

  nav a {
    font-size: 0.8rem;
  }

  .site-name strong {
    letter-spacing: 0.04em;
  }

  .intro {
    padding: 58px 0 62px;
  }

  .section {
    padding: 54px 0;
  }

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

  .history-list li {
    grid-template-columns: 1fr;
    gap: 5px;
  }

  .career-page .history-list li {
    grid-template-columns: 1fr;
  }

  .footer-inner {
    flex-direction: column;
    gap: 4px;
  }
}

@media (max-width: 820px) {
  .header-inner {
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
    padding: 16px 0;
  }

  nav {
    flex-wrap: wrap;
  }
}

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