:root {
  --bg: #f4f4f0;
  --bg-soft: #ebebe5;
  --surface: #ffffff;
  --ink: #0c0e14;
  --ink-soft: #1f2230;
  --muted: #5e6473;
  --line: #d9dae2;
  --line-strong: #b3b6c4;
  --accent: #1d3aa8;
  --accent-deep: #122572;
  --accent-soft: #e3e6f5;
  --max: 880px;
  --radius: 0;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
html, body { margin: 0; padding: 0; }

body {
  font-family: "Inter", "Noto Sans JP", -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN", sans-serif;
  font-feature-settings: "ss01", "cv11", "palt";
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 2rem;
  width: 100%;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(244, 244, 240, 0.92);
  backdrop-filter: saturate(1.2) blur(10px);
  -webkit-backdrop-filter: saturate(1.2) blur(10px);
  border-bottom: 1px solid var(--line);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1.1rem;
  padding-bottom: 1.1rem;
  gap: 1rem;
}
.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 0.55rem;
  text-decoration: none;
  color: var(--ink);
}
.brand-label {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.14em;
  color: var(--ink);
}
.brand-sep {
  color: var(--line-strong);
  font-size: 0.78rem;
}
.brand-mark {
  font-family: "JetBrains Mono", monospace;
  font-weight: 500;
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  background: var(--ink);
  color: var(--bg);
  padding: 0.25rem 0.5rem 0.22rem;
  border-radius: 0;
}
.brand-name {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 500;
  font-size: 0.82rem;
  letter-spacing: 0.18em;
  color: var(--muted);
  text-transform: uppercase;
}
.site-nav {
  display: flex;
  gap: 1.6rem;
  align-items: center;
  flex-wrap: wrap;
}
.site-nav > a {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.76rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  text-decoration: none;
  position: relative;
  padding-bottom: 2px;
  transition: color 0.2s;
}
.site-nav > a::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -1px;
  height: 1px;
  background: var(--ink);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.3s ease;
}
.site-nav > a:hover { color: var(--ink); }
.site-nav > a:hover::after { transform: scaleX(1); transform-origin: left; }

.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding-left: 1.2rem;
  margin-left: 0.2rem;
  border-left: 1px solid var(--line);
  font-family: "JetBrains Mono", monospace;
  font-size: 0.76rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.lang-switch__current { color: var(--ink); }
.lang-switch__sep { color: var(--line-strong); }
.lang-switch__alt {
  color: var(--muted);
  text-decoration: none;
  transition: color 0.2s;
}
.lang-switch__alt:hover { color: var(--accent); }

/* ---------- Page ---------- */
main.page {
  padding: 5rem 0 6rem;
  flex: 1;
  counter-reset: section;
}

.prose h1 {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 600;
  font-size: clamp(2.4rem, 4vw + 1rem, 4rem);
  line-height: 1.05;
  letter-spacing: -0.025em;
  margin: 0 0 1.5rem;
}

.prose h2 {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 600;
  font-size: clamp(1.4rem, 1.2vw + 1rem, 1.7rem);
  line-height: 1.3;
  letter-spacing: -0.012em;
  margin-top: 5rem;
  margin-bottom: 1.8rem;
  padding-top: 1.6rem;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: 3rem 1fr;
  gap: 1.4rem;
  align-items: baseline;
  counter-increment: section;
}
.prose h2::before {
  content: counter(section, decimal-leading-zero);
  font-family: "JetBrains Mono", monospace;
  font-weight: 400;
  font-size: 0.82rem;
  color: var(--muted);
  letter-spacing: 0.1em;
  padding-top: 0.35rem;
  align-self: start;
}

.prose h3 {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 600;
  font-size: 1.15rem;
  letter-spacing: -0.01em;
  margin-top: 2.5rem;
  margin-bottom: 0.6rem;
}

.prose p {
  margin: 1rem 0;
  color: var(--ink-soft);
}

.prose a {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-color: var(--line-strong);
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
  transition: text-decoration-color 0.2s, color 0.2s;
}
.prose a:hover {
  color: var(--accent);
  text-decoration-color: var(--accent);
}

.prose ul {
  padding-left: 1.4rem;
  margin: 1rem 0;
}
.prose ul li { margin: 0.3rem 0; }
.prose ul li::marker { color: var(--muted); }

.prose strong { font-weight: 600; color: var(--ink); }
.prose small { color: var(--muted); font-size: 0.82rem; letter-spacing: 0.05em; }

.prose hr {
  border: none;
  height: 1px;
  background: var(--line);
  margin: 4rem 0;
}

.prose code {
  background: var(--bg-soft);
  padding: 0.1rem 0.4rem;
  border-radius: 0;
  font-size: 0.9em;
  font-family: "JetBrains Mono", "SFMono-Regular", Menlo, monospace;
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.93rem;
}
.prose table th,
.prose table td {
  padding: 0.7rem 0.9rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
}
.prose table th {
  font-family: "JetBrains Mono", monospace;
  font-weight: 400;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--muted);
  border-bottom: 1px solid var(--ink);
}

/* ---------- Ornament reduced to a thin marker line ---------- */
.ornament {
  display: block;
  font-size: 0;
  line-height: 0;
  height: 0;
  background: transparent;
  border: none;
  border-top: 1px solid var(--line);
  margin: 5rem 0;
  max-width: 60px;
}

/* ---------- Drop cap removed ---------- */
.dropcap::first-letter,
.hero + p::first-letter,
.hero + .prose-intro::first-letter {
  all: revert;
}

/* ---------- Seal removed ---------- */
.seal { display: none; }

/* ---------- Hero ---------- */
.hero { margin: 0 0 4rem; }
.hero__eyebrow {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.76rem;
  letter-spacing: 0.18em;
  color: var(--muted);
  text-transform: uppercase;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}
.hero__eyebrow::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--line-strong);
  max-width: 14rem;
}
.hero__title {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 600;
  font-size: clamp(2.6rem, 5vw + 1rem, 4.4rem);
  line-height: 1.04;
  letter-spacing: -0.028em;
  margin: 0 0 1.2rem;
}
.hero__lead {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 400;
  color: var(--muted);
  font-size: 1.08rem;
  line-height: 1.55;
  letter-spacing: 0;
  max-width: 36em;
  margin: 0;
}
.hero__byline {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 500;
  color: var(--ink-soft);
  font-size: 0.92rem;
  letter-spacing: 0.04em;
  margin: 1.4rem 0 0;
}

/* ---------- Hero with cover ---------- */
.hero--with-cover {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 2.8rem;
  align-items: center;
}
.hero--with-cover .hero__body { min-width: 0; }
.hero__cover {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 0;
  transform: none;
  box-shadow:
    0 20px 40px -18px rgba(10, 10, 10, 0.32),
    0 6px 12px -6px rgba(10, 10, 10, 0.18);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.hero__cover:hover {
  transform: translateY(-3px);
  box-shadow:
    0 28px 50px -18px rgba(10, 10, 10, 0.4),
    0 10px 18px -6px rgba(10, 10, 10, 0.22);
}

/* ---------- Book cards ---------- */
.book-list {
  display: grid;
  gap: 1.5rem;
  margin: 1.5rem 0 0;
}
.book-card {
  display: block;
  padding: 2rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 0;
  text-decoration: none;
  color: inherit;
  position: relative;
  transition: border-color 0.2s ease;
}
.book-card::before { display: none; }
.book-card:hover {
  border-color: var(--ink);
  transform: none;
  box-shadow: none;
}
.book-card__meta {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.76rem;
  letter-spacing: 0.16em;
  color: var(--muted);
  text-transform: uppercase;
  margin-bottom: 1rem;
}
.book-card__title {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 600;
  font-size: 1.5rem;
  line-height: 1.2;
  margin: 0 0 0.4rem;
  color: var(--ink);
  letter-spacing: -0.015em;
}
.book-card__subtitle {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 400;
  font-size: 1rem;
  color: var(--muted);
  margin-bottom: 1.1rem;
  letter-spacing: 0;
}
.book-card__desc {
  margin: 0 0 1.4rem;
  color: var(--ink-soft);
  font-size: 0.96rem;
  line-height: 1.7;
}
.book-card__cta {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.76rem;
  letter-spacing: 0.16em;
  color: var(--ink);
  text-transform: uppercase;
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
}
.book-card__cta .arrow {
  display: inline-block;
  transition: transform 0.25s ease;
}
.book-card:hover .book-card__cta { color: var(--accent); }
.book-card:hover .book-card__cta .arrow { transform: translateX(6px); }

.book-card--with-cover {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 1.8rem;
  align-items: start;
}
.book-card--with-cover .book-card__body { min-width: 0; }
.book-card__cover {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 0;
  transform: none;
  box-shadow:
    0 10px 20px -8px rgba(10, 10, 10, 0.25),
    0 3px 6px -3px rgba(10, 10, 10, 0.15);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.book-card:hover .book-card__cover {
  transform: translateY(-2px);
  box-shadow:
    0 16px 28px -8px rgba(10, 10, 10, 0.32),
    0 5px 10px -3px rgba(10, 10, 10, 0.18);
}

/* ---------- Info grid (book metadata) ---------- */
.info-grid {
  display: grid;
  grid-template-columns: 7rem 1fr;
  gap: 0.6rem 1.6rem;
  margin: 1.8rem 0;
  padding: 1.4rem 0;
  background: transparent;
  border: none;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--line);
  border-radius: 0;
}
.info-grid dt {
  font-family: "JetBrains Mono", monospace;
  font-weight: 400;
  color: var(--muted);
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  padding-top: 0.15rem;
}
.info-grid dd {
  margin: 0;
  color: var(--ink);
  font-size: 0.98rem;
}

/* ---------- Back link ---------- */
.back-link {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.76rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
  text-decoration: none !important;
  border-bottom: none !important;
  margin-bottom: 3.5rem;
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  transition: color 0.2s;
}
.back-link:hover { color: var(--ink); }
.back-link .arrow {
  display: inline-block;
  transition: transform 0.25s ease;
}
.back-link:hover .arrow { transform: translateX(-5px); }

/* ---------- Tools (stack with rules) ---------- */
.tool {
  padding: 1.5rem 0;
  border: none;
  border-top: 1px solid var(--line);
  background: transparent;
  margin: 0;
  border-radius: 0;
}
.tool:first-of-type { border-top: 1px solid var(--ink); }
.tool:last-of-type { border-bottom: 1px solid var(--line); }
.tool:hover { transform: none; border-color: var(--line); }
.tool:first-of-type:hover { border-top-color: var(--ink); }
.tool h4 {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 600;
  font-size: 1.15rem;
  margin: 0 0 0.4rem;
  letter-spacing: -0.01em;
}
.tool h4 a {
  color: var(--ink);
  border: none;
  text-decoration: underline;
  text-decoration-color: var(--line-strong);
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
  padding-bottom: 0;
}
.tool h4 a:hover {
  color: var(--accent);
  text-decoration-color: var(--accent);
}
.tool p {
  margin: 0;
  font-size: 0.95rem;
  color: var(--ink-soft);
  line-height: 1.7;
}

/* ---------- FAQ ---------- */
.faq-item {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--line);
}
.faq-item:first-of-type { border-top: 1px solid var(--ink); }
.faq-item .q {
  font-family: "Inter", "Noto Sans JP", sans-serif;
  font-weight: 600;
  font-size: 1.02rem;
  color: var(--ink);
  margin: 0 0 0.6rem;
  padding-left: 2rem;
  position: relative;
  letter-spacing: -0.005em;
}
.faq-item .q::before {
  content: "Q";
  position: absolute;
  left: 0;
  top: 0.2em;
  font-family: "JetBrains Mono", monospace;
  font-weight: 400;
  font-size: 0.78rem;
  color: var(--accent);
  letter-spacing: 0.1em;
}
.faq-item .a {
  padding-left: 2rem;
  position: relative;
  color: var(--ink-soft);
  font-size: 0.96rem;
  margin: 0;
  line-height: 1.7;
}
.faq-item .a::before {
  content: "A";
  position: absolute;
  left: 0;
  top: 0.15em;
  font-family: "JetBrains Mono", monospace;
  font-weight: 400;
  font-size: 0.78rem;
  color: var(--muted);
  letter-spacing: 0.1em;
}

/* ---------- Contact ---------- */
.contact {
  margin: 3rem 0 1rem;
  padding: 2.5rem 0;
  background: transparent;
  border-radius: 0;
  border: none;
  border-top: 2px solid var(--ink);
  border-bottom: 1px solid var(--line);
  position: relative;
}
.contact::before { display: none; }
.contact p {
  margin: 0 0 0.8rem;
  color: var(--ink);
  font-size: 1rem;
}
.contact p:last-child { margin-bottom: 0; }
.contact .note {
  font-size: 0.88rem;
  line-height: 1.65;
  color: var(--ink-soft);
  margin: 0 0 1.3rem;
  padding-left: 1rem;
  border-left: 2px solid var(--line-strong);
}
.contact .note strong {
  font-weight: 600;
  color: var(--ink);
}
.contact a.btn {
  display: inline-block;
  margin-top: 0.5rem;
  padding: 0.85rem 1.6rem;
  background: var(--ink);
  color: var(--bg);
  border: none;
  border-radius: 0;
  font-family: "JetBrains Mono", monospace;
  font-weight: 500;
  font-size: 0.78rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  text-decoration: none;
  transition: background 0.2s;
}
.contact a.btn:hover {
  background: var(--accent);
  transform: none;
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 2.2rem 0;
  margin-top: auto;
  background: transparent;
}
.footer-ornament { display: none; }
.footer-inner {
  flex-direction: row;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  text-align: left;
}
.footer-brand {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.76rem;
  letter-spacing: 0.14em;
  color: var(--muted);
  text-transform: uppercase;
}
.site-footer small {
  font-family: "JetBrains Mono", monospace;
  font-size: 0.76rem;
  letter-spacing: 0.12em;
  color: var(--muted);
  font-style: normal;
}

/* ---------- Responsive ---------- */
@media (max-width: 720px) {
  .container { padding: 0 1.4rem; }
  .header-inner { flex-direction: column; gap: 0.8rem; align-items: flex-start; padding-top: 1rem; padding-bottom: 1rem; }
  .site-nav { gap: 1.2rem; }
  .lang-switch { padding-left: 0.9rem; margin-left: 0; }
  main.page { padding: 3rem 0 4rem; }
  .info-grid { grid-template-columns: 1fr; gap: 0.2rem; padding: 1.4rem 0; }
  .info-grid dt { margin-top: 0.6rem; }
  .info-grid dt:first-of-type { margin-top: 0; }
  .book-card { padding: 1.5rem; }
  .hero { margin-bottom: 3rem; }
  .hero--with-cover {
    grid-template-columns: 100px 1fr;
    gap: 1.4rem;
  }
  .book-card--with-cover {
    grid-template-columns: 60px 1fr;
    gap: 1.2rem;
  }
  .prose h2 {
    grid-template-columns: 2.4rem 1fr;
    gap: 1rem;
    margin-top: 4rem;
  }
  .footer-inner { flex-direction: column; align-items: flex-start; }
}