:root {
  --accent: #40E0D0;
  --accent-dark: #149f98;
  --header-offset: 100px;
  --section-padding-block: clamp(3rem, 7vw, 5.5rem);
  --ink: #17202a;
  --muted: #596673;
  --line: #d8e4e3;
  --panel: #f7fbfb;
  --paper: #ffffff;
  --shadow: 0 18px 45px rgba(22, 44, 56, 0.08);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-offset);
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Segoe UI", "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
  font-size: 16px;
  line-height: 1.75;
}

a {
  color: #087c78;
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

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

.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  z-index: 10;
  padding: 0.5rem 0.75rem;
  color: var(--ink);
  background: var(--accent);
}

.skip-link:focus {
  top: 1rem;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  border-bottom: 1px solid rgba(216, 228, 227, 0.82);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
}

.top-nav {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: min(1120px, calc(100% - 32px));
  min-height: 64px;
  margin: 0 auto;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  color: var(--ink);
  font-size: 1rem;
  font-weight: 700;
  text-decoration: none;
  white-space: nowrap;
}

.brand-icon {
  display: block;
  width: 1.55rem;
  height: 1.55rem;
  object-fit: contain;
}

.nav-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.25rem 1rem;
  font-size: 0.9rem;
}

.nav-links a {
  color: var(--ink);
  text-decoration: none;
}

.nav-links a:hover,
.nav-links a:focus {
  color: var(--accent-dark);
}

.nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  flex: 0 0 42px;
  padding: 0;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
}

.nav-toggle:hover,
.nav-toggle:focus-visible {
  border-color: var(--accent-dark);
  color: var(--accent-dark);
}

.nav-toggle-icon {
  position: relative;
  display: block;
  width: 20px;
  height: 16px;
}

.nav-toggle-icon span {
  position: absolute;
  left: 0;
  width: 100%;
  height: 2px;
  background: currentColor;
  transition: top 180ms ease, transform 180ms ease, opacity 180ms ease;
}

.nav-toggle-icon span:nth-child(1) {
  top: 0;
}

.nav-toggle-icon span:nth-child(2) {
  top: 7px;
}

.nav-toggle-icon span:nth-child(3) {
  top: 14px;
}

.menu-open .nav-toggle-icon span:nth-child(1) {
  top: 7px;
  transform: rotate(45deg);
}

.menu-open .nav-toggle-icon span:nth-child(2) {
  opacity: 0;
}

.menu-open .nav-toggle-icon span:nth-child(3) {
  top: 7px;
  transform: rotate(-45deg);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  align-items: center;
  gap: clamp(1.25rem, 3vw, 2.25rem);
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 3rem 0 3.5rem;
}

.hero-text {
  max-width: 700px;
}

.eyebrow,
.section-kicker {
  margin: 0 0 0.65rem;
  color: var(--accent-dark);
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  line-height: 1.25;
}

h1 {
  margin: 0;
  font-size: 3.2rem;
  font-weight: 800;
  letter-spacing: 0;
}

.name-en {
  margin: 0.15rem 0 0.35rem;
  color: var(--muted);
  font-size: 1.18rem;
  font-weight: 600;
}

.hero-email {
  margin: 0 0 0.95rem;
  color: var(--ink);
  font-size: 0.95rem;
  font-weight: 700;
}

.affiliation {
  margin: 0 0 1rem;
  color: var(--ink);
  font-size: 1rem;
  font-weight: 600;
}

.lead {
  max-width: 650px;
  margin: 0;
  color: var(--muted);
  font-size: 1rem;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  margin-top: 1.1rem;
}

.tag-list span {
  display: inline-flex;
  align-items: center;
  min-height: 1.85rem;
  padding: 0.16rem 0.68rem;
  border: 1px solid var(--line);
  border-left: 4px solid var(--accent);
  background: var(--panel);
  color: #31434a;
  font-size: 0.84rem;
  font-weight: 650;
}

.profile-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem 1rem;
  margin-top: 1rem;
  font-size: 0.92rem;
  font-weight: 650;
}

.profile-links a {
  color: var(--ink);
  text-decoration: none;
  border-bottom: 2px solid var(--accent);
}

.profile-links a:hover,
.profile-links a:focus {
  color: var(--accent-dark);
}

.portrait {
  width: 320px;
  height: 320px;
  margin: 0 0 0 auto;
  overflow: hidden;
  box-shadow: var(--shadow);
}

.portrait img {
  display: block;
  width: 100%;
  height: 100%;
  max-width: none;
  margin-left: 0;
  object-fit: cover;
  object-position: 42% 24%;
  box-shadow: none;
}

.section {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: var(--section-padding-block) 0;
  border-top: 1px solid var(--line);
  scroll-margin-top: calc(0px - var(--section-padding-block));
}

.two-column {
  display: grid;
  grid-template-columns: minmax(180px, 0.35fr) minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 4rem);
}

.section-heading {
  max-width: 720px;
  margin-bottom: 2rem;
}

h2 {
  margin: 0;
  font-size: 2.6rem;
  font-weight: 780;
}

html[lang="ja"] #activities-title {
  word-break: keep-all;
  overflow-wrap: normal;
}

h3 {
  margin: 0 0 0.7rem;
  font-size: 1.16rem;
}

.section-body p {
  margin: 0 0 1rem;
}

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

.timeline {
  margin-top: 1.75rem;
}

.timeline h3 {
  margin-bottom: 0.9rem;
}

.timeline dl {
  display: grid;
  grid-template-columns: minmax(7rem, 0.2fr) minmax(0, 1fr);
  gap: 0.35rem 1rem;
  margin: 0;
}

.timeline dt {
  color: var(--accent-dark);
  font-weight: 750;
}

.timeline dd {
  margin: 0 0 0.35rem;
}

.research-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

.research-grid article {
  min-height: 100%;
  padding: 1.2rem;
  border: 1px solid var(--line);
  border-top: 4px solid var(--accent);
  background: var(--panel);
}

.research-grid p {
  margin: 0;
  color: var(--muted);
}

.publication-group {
  margin-top: 2.35rem;
}

.publication-group:first-of-type {
  margin-top: 0;
}

.publication-list {
  margin: 0;
  padding-left: 1.3rem;
}

.publication-list li {
  margin: 0 0 0.85rem;
  padding-left: 0.2rem;
}

.publication-list.compact li {
  margin-bottom: 0.65rem;
}

.publication-list.columns {
  columns: 2 420px;
  column-gap: 2rem;
}

.publication-list.columns li {
  break-inside: avoid;
}

.authors {
  font-weight: 400;
}

.self-author {
  font-weight: 700;
}

.title {
  font-weight: 650;
}

.venue,
.year,
.note {
  color: var(--muted);
}

.note {
  font-size: 0.92em;
}

.contact-section {
  display: grid;
  grid-template-columns: minmax(180px, 0.35fr) minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 4rem);
  background:
    linear-gradient(90deg, rgba(64, 224, 208, 0.12), transparent 44%),
    var(--paper);
}

address {
  font-style: normal;
}

.site-footer {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 2rem 0 3rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.86rem;
}

.site-footer p {
  margin: 0;
}

@media (max-width: 820px) {
  .top-nav {
    min-height: 64px;
  }

  .nav-links {
    justify-content: flex-start;
  }

  .site-header.nav-ready .nav-toggle {
    display: inline-flex;
  }

  .site-header.nav-ready .nav-links {
    position: absolute;
    top: calc(100% + 1px);
    right: 0;
    left: 0;
    z-index: 1;
    display: none;
    flex-direction: column;
    gap: 0;
    padding: 0.45rem 0;
    border: 1px solid var(--line);
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow);
  }

  .site-header.nav-ready.menu-open .nav-links {
    display: flex;
  }

  .site-header.nav-ready .nav-links a {
    display: block;
    padding: 0.6rem 0.85rem;
  }

  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
    padding-top: 2.5rem;
  }

  .portrait {
    width: 220px;
    height: 220px;
    max-width: none;
    margin-left: 0;
  }

  .portrait img {
    width: 100%;
    height: 100%;
    max-width: none;
    margin-left: 0;
    object-position: 42% 24%;
  }

  .two-column,
  .contact-section {
    grid-template-columns: 1fr;
  }

  .research-grid {
    grid-template-columns: 1fr;
  }

  h1 {
    font-size: 2.7rem;
  }

  h2 {
    font-size: 2.2rem;
  }
}

@media (max-width: 520px) {
  body {
    font-size: 15px;
  }

  .top-nav,
  .hero,
  .section,
  .site-footer {
    width: min(100% - 24px, 1120px);
  }

  h1 {
    font-size: 2.25rem;
  }

  h2 {
    font-size: 1.9rem;
  }

  .lead,
  .affiliation {
    font-size: 1rem;
  }

  .publication-list {
    padding-left: 1.1rem;
  }

  .timeline dl {
    grid-template-columns: 1fr;
    gap: 0.15rem;
  }

  .timeline dd {
    margin-bottom: 0.75rem;
  }
}