:root {
  --bg: #fafaf7;
  --surface: #ffffff;
  --surface-soft: #f4f3ee;
  --ink: #1b1d1f;
  --ink-muted: #6b6f73;
  --line: #e6e4dd;
  --line-soft: #ecead3;
  --accent: #5c8a6f;
  --accent-deep: #4a7259;
  --accent-tint: #e8efea;
  --accent-tint-strong: #d8e4dc;
  --warn: #b46a3d;
  --radius-sm: 10px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --shadow-paper: 0 1px 2px rgba(27, 29, 31, 0.04),
    0 6px 16px rgba(27, 29, 31, 0.05);
  --shadow-card: 0 1px 0 rgba(27, 29, 31, 0.03),
    0 12px 32px rgba(27, 29, 31, 0.06);
  --font-sans: "Inter", "Geist", system-ui, -apple-system, "Hiragino Sans",
    "Noto Sans JP", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo,
    monospace;
  --max-width: 1120px;
  --section-pad: clamp(64px, 9vw, 120px);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body[data-lang="ja"] {
  /* Slightly tighter line-height feels right for CJK */
  line-height: 1.75;
}

img,
svg {
  display: block;
  max-width: 100%;
}

a {
  color: var(--accent-deep);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 120ms ease, border-color 120ms ease;
}

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

button {
  font: inherit;
  color: inherit;
  cursor: pointer;
}

code {
  font-family: var(--font-mono);
  font-size: 0.92em;
  background: var(--surface-soft);
  padding: 2px 6px;
  border-radius: 6px;
  border: 1px solid var(--line-soft);
  color: var(--ink);
}

h1,
h2,
h3 {
  margin: 0;
  letter-spacing: -0.01em;
  color: var(--ink);
  line-height: 1.18;
}

h1 {
  font-size: clamp(36px, 5vw, 56px);
  font-weight: 600;
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(28px, 3.4vw, 38px);
  font-weight: 600;
}

h3 {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.005em;
}

p {
  margin: 0;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 clamp(20px, 4vw, 40px);
}

.eyebrow {
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-deep);
  margin-bottom: 14px;
}

.lead {
  font-size: clamp(16px, 1.4vw, 18px);
  color: var(--ink-muted);
  max-width: 60ch;
}

.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 12px;
  background: var(--ink);
  color: var(--bg);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  z-index: 100;
}

.skip-link:focus {
  top: 12px;
}

/* Header --------------------------------------------------------------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  background: rgba(250, 250, 247, 0.85);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 200ms ease, background 200ms ease;
}

.site-header.is-scrolled {
  border-bottom-color: var(--line);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-top: 18px;
  padding-bottom: 18px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 600;
  font-size: 17px;
  letter-spacing: -0.01em;
}

.brand:hover {
  border-bottom-color: transparent;
  color: var(--accent-deep);
}

.brand__mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--accent-tint);
  color: var(--accent-deep);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 24px);
}

.site-nav a {
  color: var(--ink-muted);
  font-size: 14px;
  font-weight: 500;
  border-bottom: 0;
}

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

.site-nav__github {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--ink);
}

.site-nav__github:hover {
  background: var(--surface);
}

.lang-toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 12px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--surface);
  font-size: 12.5px;
  font-weight: 500;
  color: var(--ink-muted);
  letter-spacing: 0.02em;
}

.lang-toggle:hover {
  color: var(--ink);
  border-color: var(--accent);
}

.lang-toggle [data-lang-label].is-active {
  color: var(--ink);
  font-weight: 600;
}

.lang-toggle__sep {
  color: var(--line);
}

.lang-toggle--ghost {
  background: transparent;
  border-color: transparent;
  padding: 4px 8px;
}

@media (max-width: 720px) {
  .site-nav a:not(.site-nav__github) {
    display: none;
  }
}

/* Hero ----------------------------------------------------------------- */

.hero {
  padding: clamp(60px, 9vw, 110px) 0 clamp(64px, 9vw, 120px);
}

.hero__inner {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
  gap: clamp(40px, 6vw, 80px);
  align-items: center;
}

.hero__copy h1 {
  margin-top: 4px;
}

.hero__copy .lead {
  margin-top: 22px;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  font-weight: 500;
  font-size: 15px;
  letter-spacing: -0.005em;
  border: 1px solid transparent;
  transition: transform 80ms ease, background 120ms ease, border-color 120ms ease,
    color 120ms ease;
}

.btn:hover {
  border-bottom-color: transparent;
  transform: translateY(-1px);
}

.btn--primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 1px 0 rgba(27, 29, 31, 0.08), 0 6px 16px rgba(92, 138, 111, 0.18);
}

.btn--primary:hover {
  background: var(--accent-deep);
  color: #fff;
}

.btn--secondary {
  background: var(--surface);
  color: var(--ink);
  border-color: var(--line);
}

.btn--secondary:hover {
  border-color: var(--accent);
  color: var(--accent-deep);
}

.hero__note {
  margin-top: 18px;
  color: var(--ink-muted);
  font-size: 13.5px;
}

/* Mock window ---------------------------------------------------------- */

.hero__art {
  position: relative;
}

.mock-window {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  overflow: hidden;
  font-size: 13px;
}

.mock-window::after {
  content: "";
  position: absolute;
  inset: -16px -16px auto auto;
  width: 120px;
  height: 120px;
  background: radial-gradient(circle, var(--accent-tint), transparent 65%);
  opacity: 0.6;
  pointer-events: none;
}

.mock-window__chrome {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 12px 14px;
  background: var(--surface-soft);
  border-bottom: 1px solid var(--line-soft);
}

.mock-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #d8d6cf;
}

.mock-dot--red {
  background: #e0a39a;
}
.mock-dot--yellow {
  background: #e1c98a;
}
.mock-dot--green {
  background: #a8c4a4;
}

.mock-window__title {
  margin-left: 12px;
  font-size: 12px;
  color: var(--ink-muted);
  letter-spacing: -0.005em;
}

.mock-window__body {
  display: grid;
  grid-template-columns: minmax(0, 0.78fr) minmax(0, 1.22fr);
  min-height: 320px;
}

.mock-sidebar {
  border-right: 1px solid var(--line-soft);
  padding: 16px 14px;
  background: linear-gradient(180deg, #fbfaf6 0%, #fdfcf8 100%);
}

.mock-sidebar__heading {
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-muted);
  margin-bottom: 12px;
  padding: 0 6px;
}

.mock-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 4px;
}

.mock-list__item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 8px 10px;
  border-radius: 8px;
  color: var(--ink);
}

.mock-list__item.is-selected {
  background: var(--accent-tint);
  color: var(--accent-deep);
}

.mock-list__label {
  font-family: var(--font-mono);
  font-size: 12px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.mock-list__meta {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--ink-muted);
  white-space: nowrap;
}

.mock-detail {
  padding: 20px 22px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.mock-detail__title {
  font-size: 17px;
  font-weight: 600;
  color: var(--ink);
}

.mock-detail__meta {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  color: var(--ink-muted);
  font-size: 12.5px;
}

.mock-detail__meta code {
  background: var(--surface-soft);
  padding: 2px 8px;
}

.mock-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}

.mock-stat {
  background: var(--surface-soft);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-sm);
  padding: 10px 12px;
}

.mock-stat__label {
  font-size: 11px;
  color: var(--ink-muted);
  letter-spacing: 0.02em;
}

.mock-stat__value {
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 17px;
  color: var(--ink);
}

.mock-actions {
  display: flex;
  gap: 8px;
  margin-top: auto;
}

.mock-btn {
  display: inline-flex;
  align-items: center;
  padding: 7px 14px;
  border-radius: 8px;
  font-size: 12.5px;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
}

.mock-btn--primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

@media (max-width: 920px) {
  .hero__inner {
    grid-template-columns: 1fr;
  }
  .mock-window__body {
    grid-template-columns: minmax(0, 0.7fr) minmax(0, 1fr);
    min-height: 280px;
  }
}

@media (max-width: 540px) {
  .mock-window__body {
    grid-template-columns: 1fr;
  }
  .mock-sidebar {
    border-right: 0;
    border-bottom: 1px solid var(--line-soft);
  }
}

/* Sections ------------------------------------------------------------- */

.section {
  padding: var(--section-pad) 0;
}

.section--surface {
  background: var(--surface);
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
}

.section__header {
  max-width: 720px;
  margin-bottom: clamp(36px, 5vw, 60px);
}

/* Features ------------------------------------------------------------- */

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

.feature-card {
  background: var(--surface);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius-md);
  padding: 26px 24px;
  transition: border-color 160ms ease, transform 160ms ease, box-shadow 160ms ease;
}

.feature-card:hover {
  border-color: var(--accent-tint-strong);
  transform: translateY(-2px);
  box-shadow: var(--shadow-paper);
}

.feature-card h3 {
  margin-bottom: 10px;
}

.feature-card p {
  color: var(--ink-muted);
  font-size: 15px;
}

@media (max-width: 880px) {
  .feature-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 560px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }
}

/* MCP ------------------------------------------------------------------ */

.mcp__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
  gap: clamp(28px, 5vw, 64px);
  align-items: center;
}

.check-list {
  list-style: none;
  padding: 0;
  margin: 26px 0 0;
  display: grid;
  gap: 14px;
}

.check-list li {
  position: relative;
  padding-left: 30px;
  color: var(--ink-muted);
  font-size: 15px;
}

.check-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--accent-tint);
  border: 1px solid var(--accent);
}

.check-list li::after {
  content: "";
  position: absolute;
  left: 4px;
  top: 12px;
  width: 8px;
  height: 4px;
  border-left: 1.6px solid var(--accent-deep);
  border-bottom: 1.6px solid var(--accent-deep);
  transform: rotate(-45deg);
}

.code-block {
  background: #20262a;
  color: #e7e6df;
  border-radius: var(--radius-md);
  padding: 22px 22px 22px 24px;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.7;
  overflow-x: auto;
  box-shadow: 0 18px 36px rgba(27, 29, 31, 0.18);
  position: relative;
}

.code-block::before {
  content: "JSON-RPC";
  position: absolute;
  top: 12px;
  right: 16px;
  font-size: 10px;
  letter-spacing: 0.18em;
  color: rgba(231, 230, 223, 0.4);
}

@media (max-width: 880px) {
  .mcp__inner {
    grid-template-columns: 1fr;
  }
}

/* Audience ------------------------------------------------------------- */

.audience {
  max-width: 760px;
}

.audience h2 {
  margin: 8px 0 22px;
}

.audience .lead + .lead {
  margin-top: 16px;
}

/* Roadmap -------------------------------------------------------------- */

.roadmap {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  gap: clamp(32px, 5vw, 64px);
}

.roadmap h3 {
  margin-bottom: 18px;
  color: var(--ink);
}

.timeline,
.planlist {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 14px;
}

.timeline li {
  display: grid;
  grid-template-columns: 64px 1fr;
  gap: 12px;
  align-items: baseline;
  padding: 14px 0;
  border-top: 1px solid var(--line-soft);
  color: var(--ink-muted);
  font-size: 15px;
}

.timeline li:last-child {
  border-bottom: 1px solid var(--line-soft);
}

.timeline__tag {
  font-family: var(--font-mono);
  font-size: 12px;
  background: var(--accent-tint);
  color: var(--accent-deep);
  padding: 2px 8px;
  border-radius: 999px;
  justify-self: start;
}

.planlist li {
  position: relative;
  padding: 12px 0 12px 28px;
  border-top: 1px dashed var(--line);
  color: var(--ink-muted);
  font-size: 15px;
}

.planlist li:last-child {
  border-bottom: 1px dashed var(--line);
}

.planlist li::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 19px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  border: 1.5px solid var(--ink-muted);
  opacity: 0.6;
}

@media (max-width: 760px) {
  .roadmap {
    grid-template-columns: 1fr;
  }
}

/* Footer --------------------------------------------------------------- */

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--bg);
  padding: 56px 0 64px;
}

.site-footer__inner {
  display: grid;
  gap: 16px;
  text-align: center;
}

.site-footer__brand {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-weight: 600;
  color: var(--ink);
}

.site-footer__tagline {
  color: var(--ink-muted);
  font-size: 14px;
}

.site-footer__links {
  display: inline-flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px 22px;
  margin: 6px auto 0;
  max-width: 720px;
}

.site-footer__links a {
  color: var(--ink-muted);
  font-size: 14px;
  border-bottom-color: transparent;
}

.site-footer__links a:hover {
  color: var(--ink);
  border-bottom-color: var(--accent);
}

.site-footer__credit {
  color: var(--ink-muted);
  font-size: 13px;
  margin-top: 8px;
}

/* Reveal animation ----------------------------------------------------- */

.reveal {
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 600ms ease, transform 600ms ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .btn:hover {
    transform: none;
  }
}