:root {
  --background: #f7f8fa;
  --surface: #ffffff;
  --surface-muted: #eef2f5;
  --text: #1f2933;
  --muted: #536170;
  --border: #d7dde3;
  --accent: #22577a;
  --accent-hover: #12384f;
  --focus: #b45309;
  --max-width: 880px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: auto;
}

@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.7;
}

a {
  color: var(--accent);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--accent-hover);
}

a:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  left: 8px;
  top: -48px;
  z-index: 100;
  padding: 8px 16px;
  border-radius: 6px;
  background: var(--accent);
  color: #ffffff;
  font-weight: 700;
  text-decoration: none;
  transition: top 0.15s ease;
}

.skip-link:focus {
  top: 8px;
  color: #ffffff;
}

.container {
  width: min(100% - 32px, var(--max-width));
  margin: 0 auto;
}

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

.header-content {
  position: relative;
  padding: 56px 0 32px;
}

.language-switch {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
  margin-bottom: 28px;
}

.language-link {
  display: inline-flex;
  min-height: 34px;
  border: 1px solid var(--border);
  border-radius: 6px;
  align-items: center;
  padding: 0 12px;
  background: var(--surface);
  color: var(--text);
  font-size: 0.9rem;
  font-weight: 700;
  text-decoration: none;
}

.language-link:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.language-link:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  font-size: clamp(2.25rem, 5vw, 3.75rem);
  line-height: 1.1;
  letter-spacing: 0;
}

h2 {
  margin: 0 0 20px;
  font-size: 1.65rem;
  line-height: 1.25;
  letter-spacing: 0;
}

h3 {
  margin: 0 0 14px;
  font-size: 1.12rem;
  line-height: 1.35;
  letter-spacing: 0;
}

.affiliation {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 1.08rem;
}

.affiliation-ja {
  margin-top: 2px;
}

.summary {
  max-width: 680px;
  margin: 20px 0 0;
  font-size: 1.04rem;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin-top: 30px;
  padding-top: 22px;
  border-top: 1px solid var(--border);
}

.site-nav a {
  display: inline-flex;
  min-height: 36px;
  align-items: center;
  color: var(--text);
  font-weight: 700;
  text-decoration: none;
}

.site-nav a:hover {
  color: var(--accent);
}

.section {
  padding: 56px 0;
  background: var(--surface);
}

.section + .section {
  border-top: 1px solid var(--border);
}

.section-muted {
  background: var(--surface-muted);
}

.section p {
  max-width: 720px;
  margin: 0;
}

.interest-list,
.external-links,
.link-list {
  margin: 0;
  padding-left: 1.25rem;
}

.interest-list li + li {
  margin-top: 6px;
}

.item-list {
  display: grid;
  gap: 18px;
}

.subsection-title {
  margin: 28px 0 14px;
  color: var(--muted);
  font-size: 1rem;
  font-weight: 700;
}

.subsection-title:first-of-type {
  margin-top: 0;
}

.publication-item,
.presentation-item,
.education-item {
  padding: 22px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
}

.metadata {
  display: grid;
  gap: 10px;
  margin: 0;
}

.metadata div {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr);
  gap: 16px;
}

.metadata dt {
  color: var(--muted);
  font-weight: 700;
}

.metadata dd {
  margin: 0;
}

.author-self {
  color: var(--text);
  font-weight: 700;
}

.link-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin-top: 16px;
  padding-left: 0;
  list-style: none;
}

.external-links {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 10px 20px;
  padding-left: 0;
  list-style: none;
}

.email {
  margin-top: 12px;
  font-weight: 700;
}

.site-footer {
  border-top: 1px solid var(--border);
  background: var(--surface);
  color: var(--muted);
  font-size: 0.94rem;
}

.footer-content {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 20px;
  padding: 24px 0;
}

.footer-content p {
  margin: 0;
}

@media (max-width: 640px) {
  .container {
    width: min(100% - 24px, var(--max-width));
  }

  .header-content {
    padding: 40px 0 26px;
  }

  .language-switch {
    justify-content: flex-start;
    margin-bottom: 24px;
  }

  .section {
    padding: 42px 0;
  }

  .site-nav {
    gap: 4px 14px;
  }

  .site-nav a {
    min-height: 34px;
  }

  .publication-item,
  .presentation-item,
  .education-item {
    padding: 18px;
  }

  .metadata div {
    grid-template-columns: 1fr;
    gap: 2px;
  }
}