:root {
  --paper: #f6f8f3;
  --paper-strong: #fffdf7;
  --ink: #17231d;
  --muted: #5f6d64;
  --line: #dfe6dc;
  --teal: #0f766e;
  --teal-deep: #0d4f49;
  --clay: #bf5f35;
  --gold: #d0a33a;
  --night: #10211c;
  --white: #ffffff;
  --shadow: 0 18px 48px rgba(23, 35, 29, 0.12);
  color-scheme: light;
  font-family:
    Inter, "Helvetica Neue", Arial, "Hiragino Sans", "Hiragino Kaku Gothic ProN",
    Meiryo, sans-serif;
  font-size: 16px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  line-height: 1.75;
}

a {
  color: inherit;
}

.site-header {
  align-items: center;
  backdrop-filter: blur(18px);
  background: rgba(246, 248, 243, 0.86);
  border-bottom: 1px solid rgba(223, 230, 220, 0.9);
  display: flex;
  justify-content: space-between;
  left: 0;
  min-height: 68px;
  padding: 0 28px;
  position: sticky;
  right: 0;
  top: 0;
  z-index: 20;
}

.brand {
  color: var(--ink);
  font-size: 0.95rem;
  font-weight: 800;
  text-decoration: none;
}

.nav {
  display: flex;
  gap: 22px;
  white-space: nowrap;
}

.nav a {
  color: var(--muted);
  font-size: 0.86rem;
  font-weight: 700;
  text-decoration: none;
}

.nav a:hover,
.text-link:hover,
.site-footer a:hover {
  color: var(--teal);
}

.lang-switch {
  align-items: center;
  border: 1.5px solid var(--line);
  border-radius: 999px;
  color: var(--muted) !important;
  display: inline-flex;
  font-size: 0.76rem;
  font-weight: 900;
  height: 26px;
  justify-content: center;
  letter-spacing: 0.04em;
  margin-left: 6px;
  min-width: 36px;
  padding: 0 9px;
  text-decoration: none;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.lang-switch:hover {
  background: var(--teal);
  border-color: var(--teal);
  color: var(--white) !important;
}

.hero {
  isolation: isolate;
  min-height: min(620px, 76svh);
  overflow: hidden;
  position: relative;
}

.hero__media {
  background-image: url("assets/hero-research.png");
  background-position: center right;
  background-size: cover;
  inset: 0;
  position: absolute;
  z-index: -2;
}

.hero__overlay {
  background:
    linear-gradient(90deg, rgba(16, 33, 28, 0.93) 0%, rgba(16, 33, 28, 0.8) 36%, rgba(16, 33, 28, 0.2) 72%),
    linear-gradient(180deg, rgba(16, 33, 28, 0.2), rgba(16, 33, 28, 0.35));
  inset: 0;
  position: absolute;
  z-index: -1;
}

.hero__content {
  color: var(--white);
  display: flex;
  flex-direction: column;
  justify-content: center;
  max-width: 1180px;
  min-height: min(620px, 76svh);
  padding: 64px 28px 52px;
  width: min(100%, 1180px);
  margin: 0 auto;
}

.eyebrow,
.section-kicker {
  color: var(--gold);
  font-size: 0.76rem;
  font-weight: 900;
  letter-spacing: 0;
  margin: 0 0 12px;
  text-transform: uppercase;
}

.hero h1 {
  font-size: clamp(2.45rem, 7vw, 4.8rem);
  letter-spacing: 0;
  line-height: 1.05;
  margin: 0;
  max-width: 760px;
}

.hero__lead {
  color: rgba(255, 255, 255, 0.86);
  font-size: clamp(1rem, 2vw, 1.25rem);
  margin: 26px 0 0;
  max-width: 720px;
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 34px;
}

.button {
  align-items: center;
  border: 1px solid rgba(255, 255, 255, 0.38);
  display: inline-flex;
  font-size: 0.95rem;
  font-weight: 800;
  justify-content: center;
  min-height: 48px;
  padding: 0 18px;
  text-decoration: none;
}

.button--primary {
  background: var(--white);
  border-color: var(--white);
  color: var(--night);
}

.button--ghost {
  color: var(--white);
}

.social-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
}

.social-links__item {
  align-items: center;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 999px;
  color: var(--white);
  display: inline-flex;
  gap: 8px;
  font-size: 0.82rem;
  font-weight: 800;
  padding: 9px 16px 9px 13px;
  text-decoration: none;
  transition:
    background 0.18s ease,
    border-color 0.18s ease,
    transform 0.18s ease;
}

.social-links__item svg {
  fill: currentColor;
  height: 18px;
  width: 18px;
}

.social-links__item:hover {
  background: var(--white);
  border-color: var(--white);
  color: var(--night);
  transform: translateY(-2px);
}

.section {
  padding: 86px 0;
}

.section--tint {
  background: var(--paper-strong);
}

.section--dark {
  background: var(--night);
  color: var(--white);
}

.section__inner {
  margin: 0 auto;
  padding: 0 28px;
  width: min(100%, 1180px);
}

.section-heading {
  align-items: end;
  display: flex;
  gap: 24px;
  justify-content: space-between;
  margin-bottom: 34px;
}

h2 {
  font-size: clamp(1.8rem, 4vw, 3.2rem);
  letter-spacing: 0;
  line-height: 1.12;
  margin: 0;
}

h3 {
  font-size: 1.12rem;
  letter-spacing: 0;
  line-height: 1.45;
  margin: 0;
}

p {
  margin: 0;
}

.intro__grid {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.intro p:not(.section-kicker) {
  color: var(--muted);
  margin-top: 18px;
  max-width: 720px;
}

.stats {
  display: flex;
  flex-wrap: wrap;
  gap: 1px;
  margin: 0;
  overflow: hidden;
}

.stats div {
  background: var(--white);
  border-left: 4px solid var(--teal);
  flex: 0 0 calc(50% - 0.5px);
  padding: 14px 16px;
}

.stats dt {
  color: var(--muted);
  font-size: 0.76rem;
  font-weight: 900;
  margin-bottom: 4px;
  text-transform: uppercase;
}

.stats dd {
  font-size: 0.92rem;
  font-weight: 800;
  margin: 0;
}

.project-grid {
  display: grid;
  gap: 18px;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.project-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 1px 0 rgba(23, 35, 29, 0.03);
  display: flex;
  flex-direction: column;
  min-height: 330px;
  padding: 24px;
}

.project-card--featured {
  background: var(--night);
  box-shadow: var(--shadow);
  color: var(--white);
  grid-column: span 2;
}

.project-card__meta {
  color: var(--teal);
  display: flex;
  flex-wrap: wrap;
  font-size: 0.76rem;
  font-weight: 900;
  gap: 10px;
  justify-content: space-between;
  margin-bottom: 18px;
  text-transform: uppercase;
}

.project-card--featured .project-card__meta,
.section--dark .section-kicker {
  color: var(--gold);
}

.project-card p {
  color: var(--muted);
  margin-top: 14px;
}

.project-card--featured p {
  color: rgba(255, 255, 255, 0.82);
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: auto;
  padding-top: 24px;
}

.tag-list span {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.18);
  color: rgba(255, 255, 255, 0.92);
  font-size: 0.78rem;
  font-weight: 800;
  padding: 5px 9px;
}

.text-link {
  color: var(--teal);
  font-weight: 900;
  margin-top: auto;
  padding-top: 18px;
  text-decoration: none;
}

.text-link-group {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: auto;
}

.text-link-group .text-link {
  margin-top: 0;
}

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

.timeline-item {
  display: grid;
  gap: 28px;
  grid-template-columns: 180px minmax(0, 1fr);
  padding: 28px 0;
  border-bottom: 1px solid var(--line);
}

.timeline-item__date {
  color: var(--clay);
  font-size: 0.86rem;
  font-weight: 900;
}

.timeline-item p:not(.timeline-item__date) {
  color: var(--muted);
  margin-top: 8px;
}

.skills-layout {
  display: grid;
  gap: 52px;
  grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr);
}

.skills-layout > div:first-child p:not(.section-kicker) {
  color: rgba(255, 255, 255, 0.78);
  margin-top: 18px;
}

.skill-groups {
  display: grid;
  gap: 1px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.skill-groups section {
  background: rgba(255, 255, 255, 0.07);
  border: 1px solid rgba(255, 255, 255, 0.08);
  min-height: 170px;
  padding: 22px;
}

.skill-groups p {
  color: rgba(255, 255, 255, 0.76);
  margin-top: 10px;
}

.publication-list {
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.pub-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 10px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

.pub-card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-3px);
}

.pub-card__image-link {
  display: block;
  position: relative;
  overflow: hidden;
  aspect-ratio: 3 / 1;
  background: var(--night);
}

.pub-card__image {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.pub-card__image-link:hover .pub-card__image {
  transform: scale(1.04);
  opacity: 0.72;
}

.pub-card__overlay {
  align-items: center;
  background: rgba(15, 118, 110, 0.85);
  border-radius: 999px;
  bottom: 14px;
  color: var(--white);
  display: flex;
  font-size: 0.82rem;
  font-weight: 800;
  justify-content: center;
  left: 50%;
  opacity: 0;
  padding: 8px 20px;
  position: absolute;
  transform: translateX(-50%) translateY(6px);
  transition: opacity 0.22s ease, transform 0.22s ease;
  white-space: nowrap;
}

.pub-card__image-link:hover .pub-card__overlay {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.pub-card__body {
  padding: 20px 22px 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex: 1;
}

.pub-card__venue {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

/* Text-only card variant (no image) */
.pub-card--text .pub-card__text-link {
  display: block;
  text-decoration: none;
}

.pub-card--text .pub-card__text-banner {
  aspect-ratio: 3 / 1;
  background: linear-gradient(135deg, var(--teal-deep) 0%, var(--teal) 60%, #14b8a6 100%);
  color: var(--white);
  display: flex;
  flex-direction: column;
  gap: 10px;
  justify-content: center;
  overflow: hidden;
  padding: 24px 22px;
  position: relative;
  transition: filter 0.2s ease;
}

.pub-card--text .pub-card__text-banner::before {
  background: radial-gradient(ellipse at top right, rgba(255,255,255,0.12) 0%, transparent 65%);
  content: "";
  inset: 0;
  pointer-events: none;
  position: absolute;
}

.pub-card--text .pub-card__text-link:hover .pub-card__text-banner {
  filter: brightness(1.1);
}

.pub-card__conf-badge {
  background: rgba(255, 255, 255, 0.18);
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: 999px;
  color: var(--white);
  font-size: 0.72rem;
  font-weight: 900;
  letter-spacing: 0.06em;
  padding: 4px 10px;
  text-transform: uppercase;
  width: fit-content;
}

.pub-card__text-title {
  color: var(--white);
  font-size: 0.88rem;
  font-weight: 700;
  line-height: 1.45;
  margin: 0;
}

.pub-card__text-cta {
  color: rgba(255, 255, 255, 0.82);
  font-size: 0.78rem;
  font-weight: 800;
  margin-top: auto;
}

.site-footer {
  align-items: center;
  border-top: 1px solid var(--line);
  color: var(--muted);
  display: flex;
  justify-content: space-between;
  padding: 26px 28px;
}

.site-footer a {
  font-weight: 800;
  text-decoration: none;
}

@media (max-width: 900px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    gap: 8px;
    padding: 14px 20px;
  }

  .nav {
    gap: 14px;
    overflow-x: auto;
    padding-bottom: 2px;
    width: 100%;
  }

  .hero,
  .hero__content {
    min-height: 78svh;
  }

  .hero__overlay {
    background:
      linear-gradient(90deg, rgba(16, 33, 28, 0.94) 0%, rgba(16, 33, 28, 0.82) 58%, rgba(16, 33, 28, 0.48) 100%),
      linear-gradient(180deg, rgba(16, 33, 28, 0.1), rgba(16, 33, 28, 0.44));
  }

  .section {
    padding: 64px 0;
  }

  .section__inner,
  .hero__content {
    padding-left: 20px;
    padding-right: 20px;
  }

  .skills-layout {
    grid-template-columns: 1fr;
  }

  .publication-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .pub-card__image-link,
  .pub-card--text .pub-card__text-banner {
    aspect-ratio: 16 / 5;
  }

  .project-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .project-card--featured {
    grid-column: span 2;
  }
}

@media (max-width: 640px) {
  .site-header {
    position: static;
  }

  .hero,
  .hero__content {
    min-height: 82svh;
  }

  .hero__content {
    padding-top: 52px;
    padding-bottom: 52px;
  }

  .button {
    width: 100%;
  }

  .section-heading {
    align-items: start;
    flex-direction: column;
    gap: 10px;
  }

  .project-grid,
  .skill-groups,
  .publication-list {
    grid-template-columns: 1fr;
  }

  .stats div {
    flex: 0 0 100%;
  }

  .project-card,
  .project-card--featured,
  .publication-list article {
    grid-column: auto;
    min-height: auto;
  }

  .timeline-item {
    gap: 8px;
    grid-template-columns: 1fr;
  }

  .site-footer {
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
  }
}