:root {
  --ink: #1f2937;
  --muted: #6b7280;
  --kana: #94a3b8;
  --accent: #0f766e;
  --accent-soft: #14b8a6;
  --band: #ecfdf5;
  --note: #fef3c7;
  --rule: #e5e7eb;
  --rule-soft: #f1f5f9;
  --ant: #b91c1c;
  --deriv: #047857;
  --phrase: #6d28d9;
  --cf: #475569;
  --max: 820px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  background: #fafaf9;
  color: var(--ink);
  font-family: "Hiragino Kaku Gothic ProN", "Yu Gothic", "Meiryo", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.55;
}

.book {
  max-width: var(--max);
  margin: 0 auto;
  padding: 24px 28px 96px;
  background: #fff;
  border-left: 1px solid var(--rule);
  border-right: 1px solid var(--rule);
  min-height: 100vh;
}

/* Cover / TOC */
.cover { text-align: center; padding: 32px 0 20px; border-bottom: 1px solid var(--rule); }
.cover h1 { margin: 0 0 6px; font-size: 26px; letter-spacing: .04em; color: var(--accent); }
.cover .subtitle { margin: 0; color: var(--muted); font-size: 14px; }

.toc h2 {
  font-size: 13px;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 24px 0 8px;
}
.toc ol { list-style: none; padding: 0; margin: 0; }
.toc a {
  display: grid;
  grid-template-columns: 64px 1fr;
  gap: 10px;
  padding: 8px 6px;
  border-bottom: 1px solid var(--rule);
  color: var(--ink);
  text-decoration: none;
}
.toc a:hover { background: var(--band); }
.toc-num { color: var(--accent); font-weight: 700; text-align: right; font-variant-numeric: tabular-nums; }
.toc-ex { font-family: "Georgia", "Times New Roman", serif; }

/* Lesson */
.lesson { margin: 4px 0 28px; }
.lesson-num {
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--muted);
  margin: 8px 0 4px;
  text-transform: uppercase;
}
.lesson-num::before { content: 'Lesson '; }
.example {
  background: var(--band);
  padding: 12px 16px;
  margin: 0 0 16px;
}
.example-en {
  margin: 0;
  font-family: "Georgia", "Times New Roman", serif;
  font-weight: 600;
  font-size: 17px;
  line-height: 1.5;
}
.example-ja {
  background: var(--note);
  padding: 10px 14px;
  margin: 16px 0 0;
  font-size: 14px;
  line-height: 1.55;
}

/* Entries */
.entries { display: flex; flex-direction: column; }
.entry { padding: 10px 0; }
.entries > .entry + .entry { border-top: 1px solid var(--rule); }

.entry-head {
  display: flex;
  align-items: baseline;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 2px;
}
.memcheck {
  display: inline-flex;
  align-items: center;
  cursor: pointer;
  user-select: none;
  align-self: center;
}
.memcheck input[type="checkbox"] {
  appearance: none;
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  margin: 0;
  border: 1.5px solid var(--muted);
  background: #fff;
  cursor: pointer;
  vertical-align: middle;
  position: relative;
}
.memcheck input[type="checkbox"]:checked {
  background: var(--accent);
  border-color: var(--accent);
}
.memcheck input[type="checkbox"]:checked::after {
  content: '';
  position: absolute;
  left: 3px;
  top: 0px;
  width: 4px;
  height: 8px;
  border: solid #fff;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}
.headword {
  margin: 0;
  font-family: "Georgia", "Times New Roman", serif;
  font-size: 20px;
  font-weight: 700;
  color: var(--accent);
  line-height: 1.2;
}
.pos {
  display: inline-block;
  border: 1px solid var(--muted);
  padding: 0 5px;
  font-size: 11px;
  color: var(--muted);
  vertical-align: middle;
  white-space: nowrap;
  line-height: 1.5;
}
.pron {
  color: var(--muted);
  font-size: 13px;
  font-family: "Georgia", serif;
}
.kana { color: var(--kana); font-family: inherit; }

/* Senses (one paragraph, ①② inline) */
.senses-line {
  margin: 2px 0 4px;
  padding-left: 14px;
  font-size: 14px;
  line-height: 1.6;
}
.sense { display: inline; }
.sense-num { font-weight: 700; color: var(--accent); margin-right: 3px; }
.cab { font-size: 12px; color: var(--muted); margin-right: 3px; }
.prefix { color: var(--muted); margin-right: 3px; font-size: 13px; }
.gloss-ja { font-weight: 600; color: var(--ink); }
.syn { color: var(--muted); font-family: "Georgia", serif; }
.ant { color: var(--ant); }
.ant em { font-style: italic; font-family: "Georgia", serif; font-weight: 600; }
.note { color: var(--muted); font-size: 13px; }
.ex { color: var(--muted); }
.ex em { font-style: italic; font-family: "Georgia", serif; }

/* Sub-section blocks (派生 / 慣用句 / 参照) — label + body, no boxes */
.block {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 10px;
  margin: 2px 0 0;
  padding-left: 14px;
  font-size: 13.5px;
  line-height: 1.55;
}
.block-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .14em;
  padding-top: 3px;
  align-self: start;
}
.block-deriv .block-label { color: var(--deriv); }
.block-phrase .block-label { color: var(--phrase); }
.block-cf .block-label { color: var(--cf); }
.block-body { min-width: 0; }

.sub { margin: 0 0 1px; }
.sub:last-child { margin-bottom: 0; }
.sub-head {
  font-family: "Georgia", "Times New Roman", serif;
  font-weight: 700;
  font-style: italic;
  color: var(--ink);
  margin: 0 2px;
}
.sub-pron { color: var(--muted); font-size: 12px; font-family: "Georgia", serif; }

.cf-line { margin: 0; color: var(--muted); }
.cf-word { color: var(--ink); font-weight: 600; font-style: italic; font-family: "Georgia", serif; }
.cf-gloss { color: var(--ink); }
.cf-sep { color: var(--rule); }

/* Memorized state: subtle dim */
.entry:has(.entry-head .memcheck input:checked) .headword { color: var(--muted); }
.sub:has(.memcheck input:checked) .sub-head { color: var(--muted); }

/* Dialogue */
.dialogue {
  margin: 18px 0 0;
  padding: 12px 16px;
  background: #f8fafc;
}
.dialogue-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .14em;
  color: var(--muted);
  margin: 0 0 8px;
  text-transform: uppercase;
}
.turn { margin: 0 0 10px; }
.turn:last-child { margin-bottom: 0; }
.turn-en {
  margin: 0;
  font-family: "Georgia", "Times New Roman", serif;
  font-size: 14px;
  line-height: 1.55;
  color: var(--ink);
}
.turn-ja {
  margin: 1px 0 0;
  font-size: 12px;
  line-height: 1.5;
  color: var(--muted);
}
.speaker {
  font-weight: 700;
  color: var(--accent);
  margin-right: 4px;
}

/* Paginate */
.paginate {
  margin-top: 32px;
  padding-top: 14px;
  border-top: 1px solid var(--rule);
}
.paginate-row {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 16px;
  align-items: center;
}
.paginate-cell { font-size: 14px; }
.paginate-prev { text-align: left; }
.paginate-home { text-align: center; }
.paginate-next { text-align: right; }
.paginate a {
  display: inline-flex;
  gap: 6px;
  align-items: baseline;
  color: var(--accent);
  text-decoration: none;
}
.paginate a:hover { text-decoration: underline; }
.paginate-arrow { font-weight: 700; }
.paginate-label { color: var(--muted); }
.paginate-prev a:hover .paginate-label,
.paginate-next a:hover .paginate-label { color: var(--accent); }
.paginate-empty { color: transparent; }

@media (max-width: 640px) {
  .book { padding: 16px 14px 80px; }
  .headword { font-size: 18px; }
  .example-en { font-size: 15px; }
  .block { grid-template-columns: 48px 1fr; gap: 6px; padding-left: 8px; }
  .senses-line { padding-left: 8px; }
}