/* ==========================================================================
   Tokens — derived from Genki I (3rd Ed.) Chapter 3, see DESIGN_NOTES.md
   ========================================================================== */
:root {
  --paper: #ffffff;
  --peach: #f6d6a8;
  --peach-soft: #fbeddb;
  --ink: #211d17;
  --ink-soft: #5c5648;
  --ink-faint: #8b8471;
  --orange: #e0672b;
  --orange-deep: #b34f1e;
  --line: #e7dfcc;
  --line-strong: #d3c19b;

  --font-jp: 'Zen Kaku Gothic New', sans-serif;
  --font-heading: 'Libre Franklin', 'Zen Kaku Gothic New', sans-serif;
  --font-serif: 'Source Serif 4', 'Zen Kaku Gothic New', serif;

  --page-max: 760px;
}

* {
  box-sizing: border-box;
}

html {
  color-scheme: light;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-serif);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--orange-deep);
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--orange-deep);
  outline-offset: 3px;
}

img {
  max-width: 100%;
}

/* ==========================================================================
   Shared chrome
   ========================================================================== */
.site-header {
  border-bottom: 3px solid var(--ink);
  padding: 2.75rem 1.5rem 2.25rem;
}

.site-header__inner {
  max-width: var(--page-max);
  margin: 0 auto;
}

.eyebrow {
  display: block;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--orange-deep);
  margin: 0 0 0.6rem;
}

.site-title {
  font-family: var(--font-heading);
  font-size: clamp(1.9rem, 4.5vw, 2.5rem);
  font-weight: 800;
  margin: 0 0 0.55rem;
  letter-spacing: -0.01em;
}

.site-subtitle {
  margin: 0;
  color: var(--ink-soft);
  font-size: 1rem;
  max-width: 46ch;
}

.back-bar {
  border-bottom: 1px solid var(--line-strong);
  padding: 1rem 1.5rem;
}

.back-bar__inner {
  max-width: var(--page-max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.back-bar__inner::before {
  content: '';
  width: 0.5rem;
  height: 0.5rem;
  border-left: 2px solid var(--orange);
  border-bottom: 2px solid var(--orange);
  transform: rotate(45deg);
  flex: none;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  text-decoration: none;
  color: var(--ink-soft);
  border-bottom: 1px solid transparent;
}

.back-link:hover {
  color: var(--orange-deep);
  border-bottom-color: var(--orange-deep);
}

.site-footer {
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 3rem 1.5rem 4rem;
  color: var(--ink-faint);
  font-size: 0.82rem;
  border-top: 1px solid var(--line);
}

/* ==========================================================================
   Index page — chapter list
   ========================================================================== */
main {
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 2.5rem 1.5rem 1rem;
}

.chapter-list {
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.ticket {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: stretch;
  background: var(--paper);
  border: 2px solid var(--ink);
  border-radius: 3px;
  overflow: hidden;
}

.ticket a {
  display: grid;
  grid-template-columns: subgrid;
  grid-column: 1 / -1;
  color: inherit;
  text-decoration: none;
}

.ticket__main {
  padding: 1.3rem 1.4rem;
  border-right: 1px dashed var(--line-strong);
  position: relative;
}

.ticket__code {
  display: block;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--orange-deep);
  margin-bottom: 0.55rem;
}

.ticket__title-ja {
  display: block;
  font-family: var(--font-jp);
  font-weight: 700;
  font-size: 1.15rem;
  margin: 0 0 0.15rem;
}

.ticket__title-en {
  display: block;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--ink-soft);
  margin: 0 0 0.65rem;
}

.ticket__contents {
  display: block;
  font-size: 0.82rem;
  color: var(--ink-faint);
  margin: 0;
}

.ticket__stub {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  padding: 1rem 1.1rem;
  min-width: 6.5rem;
  text-align: center;
  background: var(--orange);
}

.ticket__stub-count {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--paper);
  line-height: 1;
}

.ticket__stub-label {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.62rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--paper);
  opacity: 0.9;
}

.ticket__stub-open {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  color: var(--paper);
  margin-top: 0.3rem;
}

@media (prefers-reduced-motion: no-preference) {
  .ticket {
    transition: transform 0.15s ease;
  }
  .ticket:has(a:hover),
  .ticket:has(a:focus-visible) {
    transform: translateY(-1px);
  }
}

.chapter-list__empty {
  border: 1px dashed var(--line-strong);
  border-radius: 3px;
  padding: 2rem 1.5rem;
  color: var(--ink-faint);
  font-size: 0.9rem;
  text-align: center;
}

/* ==========================================================================
   Chapter page — rendered markdown ("workbook")
   ========================================================================== */
.workbook {
  padding-bottom: 3rem;
}

.workbook h1:first-of-type {
  font-family: var(--font-heading);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--orange-deep);
  margin: 0 0 0.5rem;
}

.workbook h1:first-of-type + h2 {
  font-family: var(--font-jp);
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  margin: 0 0 1.6rem;
  padding-bottom: 1.4rem;
  border-bottom: 3px solid var(--ink);
}

.workbook h1:first-of-type + h2 .chapter-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.1rem;
  height: 2.1rem;
  margin-right: 0.6rem;
  background: var(--orange);
  color: var(--paper);
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 800;
  border-radius: 4px;
  vertical-align: -0.35rem;
}

.workbook > p {
  margin: 0 0 1.2rem;
  color: var(--ink);
}

.workbook > p:has(> em:only-child) {
  display: inline-block;
  font-style: normal;
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 0.78rem;
  color: var(--orange-deep);
  background: var(--peach-soft);
  border: 1px solid var(--line-strong);
  border-radius: 3px;
  padding: 0.45rem 0.7rem;
  margin-bottom: 1.6rem;
}

.workbook > p:has(> em:only-child) em {
  font-style: normal;
}

.workbook hr {
  border: none;
  border-top: 1px solid var(--line);
  margin: 2.4rem 0;
}

/* Numbered section headings: "## 1. Greetings That Always Work" */
.workbook h2.section-heading {
  display: flex;
  align-items: baseline;
  gap: 0.7rem;
  font-family: var(--font-jp);
  font-size: 1.3rem;
  font-weight: 700;
  margin: 2.6rem 0 1.1rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--line-strong);
}

.workbook h2.section-heading .section-num {
  flex: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.9rem;
  height: 1.9rem;
  border-radius: 50%;
  background: var(--orange);
  color: var(--paper);
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 800;
}

/* Reference headings without a number, e.g. "## Vocabulary" — styled like
   the book's section-level titles (letter-spaced English word between two
   orange rules). */
.workbook h2.label-heading {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.1rem;
  letter-spacing: 0.55em;
  text-transform: uppercase;
  color: var(--ink);
  text-indent: 0.55em; /* compensate for trailing letter-spacing gap */
  margin: 2.6rem 0 1rem;
  padding-top: 0.6rem;
  padding-bottom: 0.6rem;
  border-top: 3px solid var(--orange);
  border-bottom: 1px solid var(--orange);
}

/* Situation: / Tips: labelled paragraphs */
.workbook p.callout {
  border-left: 3px solid var(--orange);
  padding: 0.15rem 0 0.15rem 0.9rem;
  margin: 1.3rem 0 0.9rem;
}

.workbook p.callout strong {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--orange-deep);
  display: block;
  margin-bottom: 0.35rem;
}

.workbook p.callout.tips-label + ul {
  border-left: 3px solid var(--orange);
  margin: -0.9rem 0 1.6rem;
  padding: 0 0 0.2rem 0.9rem;
  list-style: none;
}

.workbook p.callout.tips-label + ul li {
  position: relative;
  padding-left: 1.1rem;
  margin-bottom: 0.7rem;
}

.workbook p.callout.tips-label + ul li::before {
  content: '—';
  position: absolute;
  left: 0;
  color: var(--ink-faint);
}

.workbook ul,
.workbook ol {
  padding-left: 1.3rem;
  margin: 0 0 1.2rem;
}

.workbook li {
  margin-bottom: 0.4rem;
}

.workbook blockquote {
  margin: 1.6rem 0;
  padding: 0.9rem 1.1rem;
  border: 1px dashed var(--line-strong);
  background: var(--peach-soft);
  border-radius: 3px;
  color: var(--ink-soft);
  font-size: 0.92rem;
}

.workbook blockquote p {
  margin: 0;
}

/* Tables — workbook vocab / phrase grids */
.workbook table {
  width: 100%;
  border-collapse: collapse;
  margin: 0 0 1.8rem;
  font-size: 0.92rem;
}

.workbook th,
.workbook td {
  border: 1px solid var(--line-strong);
  padding: 0.55rem 0.7rem;
  text-align: left;
  vertical-align: top;
}

.workbook td {
  font-family: var(--font-serif);
}

.workbook thead th {
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.workbook tbody tr:nth-child(even) td {
  background: var(--peach-soft);
}

.workbook strong {
  font-weight: 700;
}

/* Vocabulary panel — peach backdrop with a white card, echoing the book's
   two-tier "単語" spread. Built by script.js around the Vocabulary section. */
.vocab-panel {
  background: var(--peach);
  border-radius: 6px;
  padding: 1px 1.25rem 1.5rem;
  margin: 2.6rem 0;
}

.vocab-panel .label-heading {
  border-top: none;
  border-bottom: none;
  color: var(--ink);
  margin-top: 1.5rem;
  padding-top: 0;
  padding-bottom: 0;
}

.vocab-panel__card {
  background: var(--paper);
  border-radius: 5px;
  padding: 1.4rem 1.4rem 0.4rem;
  border: 1px solid var(--line-strong);
}

.vocab-panel__card table {
  margin-bottom: 1.2rem;
}

.vocab-panel__card > p:has(> em:only-child) {
  margin-bottom: 1.4rem;
}

.error-note {
  border: 1px dashed var(--line-strong);
  border-radius: 4px;
  padding: 1.6rem;
  color: var(--ink-soft);
  font-size: 0.92rem;
}

@media (max-width: 560px) {
  .ticket {
    grid-template-columns: 1fr;
  }
  .ticket a {
    grid-template-columns: 1fr;
  }
  .ticket__main {
    border-right: none;
    border-bottom: 1px dashed var(--line-strong);
  }
  .ticket__stub {
    flex-direction: row;
    justify-content: space-between;
  }
  .workbook h2.label-heading {
    letter-spacing: 0.25em;
  }
}