:root {
  --background: #f3f1eb;
  --text: #141414;
  --muted: #66645f;
  --line: #c9c5bc;
  --accent: #ff5c35;
  --panel: #e9e5dc;
  --max-width: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family: Arial, "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, Helvetica, sans-serif;
  line-height: 1.55;
}

a {
  color: inherit;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 20px 28px;
  background: color-mix(in srgb, var(--background) 88%, transparent);
  backdrop-filter: blur(12px);
}

.brand {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border: 2px solid var(--text);
  border-radius: 50%;
  font-weight: 800;
  text-decoration: none;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 28px;
}

nav {
  display: flex;
  gap: 24px;
}

nav a {
  text-decoration: none;
  font-size: 0.95rem;
}

nav a:hover {
  text-decoration: underline;
  text-underline-offset: 5px;
}

.language-switcher {
  display: flex;
  gap: 3px;
  padding: 3px;
  border: 1px solid var(--line);
  background: var(--panel);
}

.language-switcher button {
  min-height: 32px;
  padding: 5px 9px;
  border: 0;
  color: var(--muted);
  background: transparent;
  font: inherit;
  font-size: 0.72rem;
  font-weight: 800;
  cursor: pointer;
}

.language-switcher button.active {
  color: var(--background);
  background: var(--text);
}

main,
footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding-inline: 28px;
}

.hero {
  min-height: 78vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 70px 0 100px;
  border-bottom: 1px solid var(--line);
}

.eyebrow,
.section-label,
.tag {
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.76rem;
  font-weight: 700;
}

.eyebrow {
  color: var(--accent);
}

h1 {
  margin: 16px 0 24px;
  max-width: 920px;
  font-size: clamp(3.5rem, 9vw, 7.5rem);
  line-height: 0.86;
  letter-spacing: -0.075em;
}

.hero-copy {
  max-width: 720px;
  margin: 0;
  color: var(--muted);
  font-size: clamp(1.1rem, 2vw, 1.45rem);
}

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

.button {
  display: inline-block;
  padding: 13px 18px;
  border: 1px solid var(--text);
  text-decoration: none;
  font-weight: 700;
}

.button.primary {
  background: var(--text);
  color: var(--background);
}

.button:hover {
  transform: translateY(-2px);
}

.section {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 60px;
  padding: 110px 0;
  border-bottom: 1px solid var(--line);
}

.section.stacked {
  display: block;
}

.section h2 {
  max-width: 650px;
  margin: 12px 0 0;
  font-size: clamp(2rem, 5vw, 4.5rem);
  line-height: 1;
  letter-spacing: -0.045em;
}

.section-copy {
  max-width: 650px;
  color: var(--muted);
  font-size: 1.15rem;
}

.research-intro {
  color: var(--text);
  font-size: 1.28rem;
}

.research-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 30px;
}

.research-tags span {
  padding: 8px 11px;
  border: 1px solid var(--line);
  color: var(--text);
  background: var(--panel);
  font-size: 0.78rem;
  font-weight: 700;
}

.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 32px;
}

.card,
.software-card {
  background: var(--panel);
  border: 1px solid var(--line);
}

.card {
  min-height: 330px;
  padding: 28px;
}

.card-number {
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 700;
}

.card h3,
.software-card h3 {
  margin: 60px 0 14px;
  font-size: 1.55rem;
}

.card p,
.software-card p {
  color: var(--muted);
}

.software-grid {
  display: grid;
  gap: 14px;
  margin-top: 32px;
}

.software-card {
  display: flex;
  justify-content: space-between;
  gap: 28px;
  padding: 30px;
}

.software-card h3 {
  margin: 10px 0;
}

.software-card > div {
  max-width: 720px;
}

.software-card > a {
  align-self: flex-end;
  white-space: nowrap;
  font-weight: 700;
  text-decoration: none;
}

.featured-project {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(260px, 0.5fr);
  gap: 60px;
  margin-top: 32px;
  padding: clamp(28px, 5vw, 60px);
  border: 1px solid var(--line);
  background: var(--panel);
}

.featured-project h2 {
  margin: 12px 0 22px;
  max-width: none;
  font-size: clamp(2.6rem, 7vw, 6rem);
}

.project-copy > p:not(.tag) {
  max-width: 720px;
  color: var(--muted);
  font-size: 1.12rem;
}

.project-features {
  display: grid;
  gap: 10px;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}

.project-features li {
  display: flex;
  align-items: baseline;
  gap: 10px;
  color: var(--muted);
}

.project-features li::before {
  content: "↳";
  color: var(--accent);
  font-weight: 900;
}

.project-action {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  justify-content: space-between;
  gap: 40px;
}

.project-symbol {
  color: var(--accent);
  font-size: clamp(6rem, 14vw, 12rem);
  line-height: 0.8;
}

.project-action .button {
  text-align: center;
}

.contact {
  display: block;
}

.contact p {
  color: var(--muted);
}

.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  margin-top: 32px;
}

.contact-links a {
  font-weight: 700;
  text-underline-offset: 5px;
}

footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding-top: 34px;
  padding-bottom: 34px;
  color: var(--muted);
  font-size: 0.9rem;
}

@media (max-width: 800px) {
  .site-header {
    align-items: flex-start;
    padding-inline: 18px;
  }

  .header-actions {
    flex-direction: column-reverse;
    align-items: flex-end;
    gap: 11px;
  }

  nav {
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 7px 13px;
    font-size: 0.85rem;
  }

  main,
  footer {
    padding-inline: 18px;
  }

  .section {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 76px 0;
  }

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

  .card {
    min-height: 250px;
  }

  .software-card,
  footer {
    flex-direction: column;
  }

  .featured-project {
    grid-template-columns: 1fr;
    gap: 36px;
  }

  .project-action {
    align-items: flex-start;
  }

  .project-symbol {
    display: none;
  }

  .software-card > a {
    align-self: flex-start;
  }
}

@media (max-width: 520px) {
  .site-header {
    position: relative;
  }

  .brand {
    flex: 0 0 auto;
  }

  .header-actions {
    width: calc(100% - 58px);
  }

  nav {
    font-size: 0.78rem;
  }

  .hero {
    min-height: auto;
    padding-top: 86px;
  }

  h1 {
    font-size: clamp(2.9rem, 14vw, 4.4rem);
  }
}