:root {
  --bg: #0a0e1a;
  --bg-alt: #0f1424;
  --surface: #131a2e;
  --border: #232b45;
  --text: #e7eaf3;
  --text-muted: #9aa3bf;
  --sky: #38bdf8;
  --nova: #a855f7;
  --gradient: linear-gradient(120deg, var(--sky), var(--nova));
  --radius: 14px;
  --max-width: 1120px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Noto Sans JP", sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

a {
  color: inherit;
  text-decoration: none;
}

h1, h2, h3 {
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.15;
}

.eyebrow {
  text-transform: uppercase;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--sky);
  margin-bottom: 10px;
}

/* Language toggle — both languages live in the DOM at all times (good for
   crawlers/automated review that don't execute JS); this only hides one
   side visually. */
body[data-lang="en"] .lang-ja { display: none; }
body[data-lang="ja"] .lang-en { display: none; }

.lang-switch {
  display: flex;
  gap: 2px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px;
}

.lang-switch button {
  border: none;
  background: transparent;
  color: var(--text-muted);
  font-size: 13px;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 999px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.lang-switch button.active {
  background: var(--gradient);
  color: #0a0e1a;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 14, 26, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: 20px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -0.01em;
  white-space: nowrap;
}

.logo-mark {
  width: 22px;
  height: 22px;
  border-radius: 7px;
  background: var(--gradient);
  display: inline-block;
}

.logo .accent {
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 28px;
  flex: 1;
  justify-content: flex-end;
}

.main-nav a {
  font-size: 15px;
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.2s ease;
  white-space: nowrap;
}

.main-nav a:hover {
  color: var(--text);
}

.nav-cta {
  padding: 9px 18px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text) !important;
}

.nav-cta:hover {
  border-color: var(--sky);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: none;
  border: none;
  cursor: pointer;
  flex-shrink: 0;
}

.nav-toggle span {
  width: 100%;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: all 0.2s ease;
}

/* Hero */
.hero {
  padding: 110px 0 80px;
  background:
    radial-gradient(60% 50% at 50% 0%, rgba(56, 189, 248, 0.14), transparent 70%),
    radial-gradient(40% 40% at 80% 20%, rgba(168, 85, 247, 0.12), transparent 70%);
}

.hero-inner {
  max-width: 780px;
  text-align: center;
  margin: 0 auto;
}

.founded-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 16px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--border);
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 26px;
}

.founded-badge .dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--gradient);
}

.hero h1 {
  font-size: clamp(32px, 4.6vw, 52px);
  margin-bottom: 22px;
}

.hero-lead {
  font-size: 18px;
  color: var(--text-muted);
  max-width: 620px;
  margin: 0 auto 36px;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 14px;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 13px 26px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 15px;
  transition: all 0.2s ease;
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--gradient);
  color: #0a0e1a;
}

.btn-primary:hover {
  filter: brightness(1.08);
  transform: translateY(-1px);
}

.btn-ghost {
  background: transparent;
  border-color: var(--border);
  color: var(--text);
}

.btn-ghost:hover {
  border-color: var(--sky);
}

.btn-lg {
  padding: 16px 32px;
  font-size: 16px;
}

/* Sections generic */
section {
  padding: 88px 0;
}

section h2 {
  font-size: clamp(25px, 3.2vw, 34px);
  margin-bottom: 20px;
}

.section-lead {
  color: var(--text-muted);
  font-size: 16px;
  max-width: 720px;
  margin-bottom: 40px;
}

/* At-a-glance facts grid */
.facts {
  background: var(--bg-alt);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 56px 0;
}

.facts-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px 32px;
}

.fact dt {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.fact dd {
  font-size: 15px;
  font-weight: 600;
}

/* Thesis */
.thesis-body p {
  color: var(--text-muted);
  max-width: 760px;
  margin-bottom: 18px;
  font-size: 16px;
}

/* Approach cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.card:hover {
  border-color: var(--sky);
  transform: translateY(-2px);
}

.card-icon {
  font-size: 26px;
  margin-bottom: 18px;
}

.card h3 {
  font-size: 18px;
  margin-bottom: 10px;
}

.card p {
  color: var(--text-muted);
  font-size: 14.5px;
}

/* Method callout */
.method {
  background: var(--bg-alt);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.method-inner {
  max-width: 760px;
}

.method-inner p {
  color: var(--text-muted);
  font-size: 16px;
}

/* Roadmap */
.roadmap {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0;
  max-width: 780px;
}

.roadmap li {
  position: relative;
  padding: 0 0 36px 32px;
  border-left: 2px solid var(--border);
}

.roadmap li:last-child {
  padding-bottom: 0;
}

.roadmap li::before {
  content: "";
  position: absolute;
  left: -7px;
  top: 2px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--surface);
  border: 2px solid var(--border);
}

.roadmap li.current {
  border-left-color: var(--sky);
}

.roadmap li.current::before {
  background: var(--gradient);
  border-color: var(--sky);
}

.roadmap .phase-label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.roadmap li.current .phase-label {
  color: var(--sky);
}

.roadmap h3 {
  font-size: 17px;
  margin-bottom: 8px;
}

.roadmap p {
  color: var(--text-muted);
  font-size: 15px;
}

/* Founder */
.founder-inner {
  display: grid;
  grid-template-columns: 1fr;
  max-width: 760px;
}

.founder-inner p {
  color: var(--text-muted);
  font-size: 16px;
  margin-bottom: 18px;
}

/* Funding */
.funding-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 18px;
  max-width: 760px;
  margin-bottom: 28px;
}

.funding-list li {
  display: flex;
  gap: 16px;
  padding: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.funding-list .f-icon {
  font-size: 22px;
  flex-shrink: 0;
}

.funding-list h3 {
  font-size: 16px;
  margin-bottom: 4px;
}

.funding-list p {
  color: var(--text-muted);
  font-size: 14.5px;
}

.funding-note {
  color: var(--text-muted);
  font-size: 15px;
  max-width: 720px;
}

/* Contact */
.contact {
  text-align: center;
}

.contact-inner {
  max-width: 600px;
  margin: 0 auto;
}

.contact-lead {
  color: var(--text-muted);
  margin-bottom: 28px;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 32px 0;
}

.footer-inner {
  font-size: 13px;
  color: var(--text-muted);
  text-align: center;
}

/* Responsive */
@media (max-width: 860px) {
  .card-grid {
    grid-template-columns: 1fr;
  }
  .facts-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 720px) {
  .header-inner {
    flex-wrap: wrap;
    height: auto;
    padding: 14px 0;
    gap: 12px;
  }
  .main-nav {
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--bg-alt);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: 8px 24px 20px;
    transform: translateY(-110%);
    opacity: 0;
    transition: all 0.25s ease;
    pointer-events: none;
  }
  .main-nav.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }
  .main-nav a {
    padding: 12px 0;
    width: 100%;
    border-bottom: 1px solid var(--border);
  }
  .nav-cta {
    margin-top: 8px;
    text-align: center;
  }
  .nav-toggle {
    display: flex;
  }
  .hero {
    padding: 90px 0 60px;
  }
  section {
    padding: 64px 0;
  }
  .facts-grid {
    grid-template-columns: 1fr;
  }
}