:root {
  --bg: #fdfcfa;
  --text: #18180f;
  --muted: #8a8880;
  --accent: #0b6b4f;
  --paper: #f7f6f3;
  --gutter: clamp(24px, 5vw, 80px);
  --max-w: 860px;
  --font: "Noto Serif JP", "Yu Mincho", "YuMincho", "Hiragino Mincho ProN", "MS PMincho", serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.9;
  letter-spacing: .02em;
  -webkit-font-smoothing: antialiased;
}

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

/* ── Header ── */
.header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(253, 252, 250, .95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid #e8e6e0;
}

.header-inner {
  max-width: calc(var(--max-w) + var(--gutter) * 2);
  margin: 0 auto;
  padding: 0 var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  height: 64px;
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-shrink: 0;
}

.brand-kicker {
  color: var(--muted);
  font-size: 10px;
  letter-spacing: .22em;
  text-transform: uppercase;
}

.brand-name {
  font-size: 22px;
  font-weight: 300;
  letter-spacing: .04em;
}

/* ── Nav ── */
.nav-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  gap: 4px;
}

.nav-list a {
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding: 8px 14px;
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--text);
  transition: color .2s;
}

.nav-list a:hover { color: var(--accent); }

.nav-num {
  color: var(--muted);
  font-size: 10px;
}

/* ── Main ── */
main {
  max-width: calc(var(--max-w) + var(--gutter) * 2);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* ── Hero ── */
.hero {
  padding: clamp(64px, 10vw, 120px) 0 clamp(48px, 7vw, 80px);
}

.hero-label {
  margin-bottom: 16px;
  color: var(--muted);
  font-size: 11px;
  letter-spacing: .22em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(36px, 6vw, 72px);
  font-weight: 300;
  line-height: 1;
  letter-spacing: -.04em;
}

.copy {
  max-width: 520px;
  margin-top: 24px;
  color: #555;
  font-size: clamp(14px, 1.4vw, 17px);
  font-weight: 300;
}

/* ── Chapters ── */
.chapter {
  display: grid;
  grid-template-columns: 100px 1fr;
  gap: clamp(24px, 4vw, 48px);
  padding: clamp(48px, 7vw, 80px) 0;
  border-top: 1px solid #e8e6e0;
}

.chapter-index {
  color: var(--muted);
  font-size: 10px;
  letter-spacing: .2em;
  text-transform: uppercase;
  padding-top: 6px;
}

.num {
  display: block;
  color: var(--accent);
  font-size: 36px;
  font-weight: 300;
  line-height: 1;
  margin-bottom: 6px;
}

h2 {
  margin: 0 0 20px;
  font-size: clamp(26px, 3.5vw, 44px);
  font-weight: 300;
  line-height: 1.2;
  letter-spacing: -.03em;
}

p {
  margin: 0 0 20px;
  color: #555;
  font-weight: 300;
}

/* ── Table ── */
.table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

table {
  width: 100%;
  min-width: 480px;
  border-collapse: collapse;
  font-size: 13px;
}

th, td {
  padding: 14px 12px 14px 0;
  text-align: left;
  vertical-align: top;
  white-space: nowrap;
  font-weight: 300;
}

th {
  color: var(--muted);
  font-size: 10px;
  letter-spacing: .16em;
  text-transform: uppercase;
  font-weight: 400;
  border-bottom: 1px solid #e8e6e0;
}

td { border-bottom: 1px solid #f0ede8; }

/* ── Box ── */
.box {
  padding: 24px 28px;
  background: var(--paper);
  color: #555;
  font-size: 14px;
  font-weight: 300;
}

/* ── Contact ── */
.contact {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0 32px;
}

.item {
  padding: 14px 0;
  font-size: 13px;
  border-bottom: 1px solid #f0ede8;
}

.label {
  color: var(--muted);
  font-size: 10px;
  letter-spacing: .2em;
  text-transform: uppercase;
}

.note {
  font-size: 11px;
  color: var(--muted);
}

/* ── Footer ── */
footer {
  max-width: calc(var(--max-w) + var(--gutter) * 2);
  margin: 0 auto;
  padding: clamp(32px, 5vw, 48px) var(--gutter);
  border-top: 1px solid #e8e6e0;
  color: var(--muted);
  font-size: 11px;
  line-height: 2;
}

.home {
  display: inline-block;
  margin-bottom: 12px;
  color: var(--text);
}

/* ── Responsive: mobile ── */
@media (max-width: 640px) {
  .header-inner { height: 56px; }
  .brand-kicker { display: none; }
  .nav-list a { padding: 8px 10px; }

  .chapter {
    grid-template-columns: 1fr;
    gap: 0;
  }

  .chapter-index {
    display: flex;
    align-items: baseline;
    gap: 12px;
    padding-bottom: 12px;
  }

  .num { display: inline; font-size: 28px; margin: 0; }

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

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}