:root {
  --bg: #fbf9f5;
  --surface: #ffffff;
  --ink: #23201c;
  --ink-soft: #5d564c;
  --ink-faint: #8a8177;
  --rule: #e2dcd1;
  --accent: #7a5c2e;
  --accent-soft: #f2ece0;
  --maxw: 46rem;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #171512;
    --surface: #201d19;
    --ink: #ece7de;
    --ink-soft: #b4ab9d;
    --ink-faint: #8a8177;
    --rule: #35302a;
    --accent: #d3b183;
    --accent-soft: #2a251e;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", serif;
  font-size: 16px;
  line-height: 1.9;
  letter-spacing: .02em;
}

.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding-inline: 20px;
}

/* ---- header ---- */

.site-head {
  border-bottom: 1px solid var(--rule);
  background: var(--surface);
}

.site-head .wrap {
  padding-block: 22px;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
  align-items: baseline;
}

.site-name {
  margin: 0;
  font-size: 1.15rem;
  letter-spacing: .16em;
  font-weight: 600;
}

.site-name a { color: inherit; text-decoration: none; }

.site-tag {
  margin: 0;
  font-size: .8rem;
  color: var(--ink-faint);
  letter-spacing: .1em;
}

/* ---- hero ---- */

.hero {
  padding-block: 56px 40px;
  border-bottom: 1px solid var(--rule);
}

.hero h1 {
  margin: 0 0 .6em;
  font-size: clamp(1.5rem, 5.2vw, 2.1rem);
  line-height: 1.5;
  letter-spacing: .08em;
  font-weight: 600;
}

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

.hero p:last-child { margin-bottom: 0; }

/* ---- sections ---- */

main section {
  padding-block: 44px;
  border-bottom: 1px solid var(--rule);
}

main section:last-of-type { border-bottom: 0; }

h2 {
  margin: 0 0 1.1em;
  font-size: 1.12rem;
  letter-spacing: .12em;
  font-weight: 600;
  padding-inline-start: .7em;
  border-inline-start: 3px solid var(--accent);
}

h3 {
  margin: 0 0 .5em;
  font-size: 1rem;
  letter-spacing: .06em;
  font-weight: 600;
}

p { margin: 0 0 1.1em; }

p:last-child { margin-bottom: 0; }

a { color: var(--accent); text-underline-offset: .2em; }

/* ---- book cards ---- */

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

.books li {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 18px 20px;
}

.books .vol {
  display: block;
  font-size: .74rem;
  letter-spacing: .2em;
  color: var(--ink-faint);
  margin-bottom: .3em;
}

.books h3 { margin-bottom: .45em; }

.books p {
  margin: 0 0 .7em;
  font-size: .92rem;
  color: var(--ink-soft);
  line-height: 1.85;
}

.meta {
  margin: 0;
  font-size: .8rem;
  color: var(--ink-faint);
  letter-spacing: .04em;
}

/* ---- prefecture index ---- */

.pref-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.pref-list a {
  display: block;
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 16px 20px;
  text-decoration: none;
  color: inherit;
}

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

.pref-list strong {
  display: block;
  font-size: 1.02rem;
  letter-spacing: .1em;
  font-weight: 600;
  margin-bottom: .2em;
}

.pref-list span {
  font-size: .84rem;
  color: var(--ink-faint);
}

/* ---- errata ---- */

.errata {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
  counter-reset: e;
}

.errata > li {
  background: var(--accent-soft);
  border-radius: 3px;
  padding: 18px 20px;
}

.errata h3 {
  font-size: .95rem;
  margin-bottom: .6em;
}

.errata dl {
  margin: 0;
  font-size: .9rem;
  line-height: 1.85;
}

.errata dt {
  font-size: .74rem;
  letter-spacing: .14em;
  color: var(--ink-faint);
  margin-top: .7em;
}

.errata dt:first-child { margin-top: 0; }

.errata dd { margin: .1em 0 0; }

.errata .was { color: var(--ink-soft); }

.errata .now { font-weight: 600; }

.errata .status {
  margin: .9em 0 0;
  font-size: .8rem;
  color: var(--ink-faint);
  padding-top: .7em;
  border-top: 1px solid var(--rule);
}

.none {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 18px 20px;
  font-size: .92rem;
  color: var(--ink-soft);
  margin: 0;
}

/* ---- contact ---- */

.contact-mail {
  font-size: 1.02rem;
  letter-spacing: .04em;
  word-break: break-all;
}

/* ---- footer ---- */

.site-foot {
  border-top: 1px solid var(--rule);
  background: var(--surface);
  margin-top: 8px;
}

.site-foot .wrap {
  padding-block: 28px 36px;
  font-size: .8rem;
  color: var(--ink-faint);
  letter-spacing: .06em;
}

.site-foot p { margin: 0 0 .5em; }

.site-foot a { color: var(--ink-soft); }

.back {
  display: inline-block;
  margin-bottom: 1.4em;
  font-size: .84rem;
  letter-spacing: .08em;
  text-decoration: none;
}

.back::before { content: "← "; }