:root {
  --color-bg: #F7F4EE;
  --color-ink: #1F1D1A;
  --color-muted: #6B655C;
  --color-accent: #B4552D;
  --color-accent-2: #3F6B5A;
  --color-line: #E4DED2;
  --color-surface: #FFFFFF;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --container: 1120px;
  --reading: 760px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", sans-serif;
}

/* ============ base ============ */

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-ink);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  font-weight: 400;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-ink);
  text-decoration: none;
}

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

h1,
h2,
h3 {
  margin: 0;
  font-weight: 600;
  line-height: 1.35;
  color: var(--color-ink);
}

p {
  margin: 0 0 1em;
}

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

ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

table {
  border-collapse: collapse;
  width: 100%;
}

th,
td {
  text-align: left;
  vertical-align: top;
}

figure {
  margin: 0;
}

figcaption {
  font-size: 14px;
  line-height: 1.6;
  color: var(--color-muted);
  margin-top: 8px;
}

time {
  font-variant-numeric: tabular-nums;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ============ layout ============ */

.site-body {
  background: var(--color-bg);
  color: var(--color-ink);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.site-main {
  flex: 1 1 auto;
  width: 100%;
}

.home-main {
  padding-bottom: 56px;
}

.inner-main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px 56px;
}

.site-inner {
  width: 100%;
}

/* ============ header ============ */

.site-header {
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-line);
}

.header-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  font-size: 19px;
  font-weight: 700;
  color: var(--color-ink);
  line-height: 1.4;
  padding: 6px 0;
  flex-shrink: 0;
}

.brand:hover {
  color: var(--color-accent);
}

.site-nav {
  flex: 1 1 auto;
  display: flex;
  justify-content: flex-end;
}

.nav-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px 22px;
}

.nav-list li {
  display: block;
}

.nav-list a {
  display: inline-block;
  padding: 10px 0;
  font-size: 15px;
  color: var(--color-ink);
  line-height: 1.4;
}

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

.nav-list a.is-current {
  font-weight: 700;
  color: var(--color-ink);
  border-bottom: 2px solid var(--color-accent);
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  cursor: pointer;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  flex-shrink: 0;
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-ink);
}

/* ============ footer ============ */

.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-line);
  margin-top: auto;
}

.footer-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 40px 24px 28px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 28px 40px;
}

.footer-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-ink);
  margin-bottom: 12px;
}

.footer-list li {
  margin-bottom: 8px;
}

.footer-list a {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.6;
}

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

.footer-bottom {
  border-top: 1px solid var(--color-line);
}

.footer-bottom p {
  max-width: var(--container);
  margin: 0 auto;
  padding: 16px 24px 0;
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.6;
}

.footer-copy {
  padding-bottom: 24px !important;
}

/* ============ components ============ */

.section {
  max-width: var(--container);
  margin: 0 auto;
  padding: 40px 24px 0;
}

.section-head {
  margin-bottom: 20px;
}

.section-head h2 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 8px;
}

.section-lead {
  font-size: 15px;
  color: var(--color-muted);
  line-height: 1.7;
  max-width: var(--reading);
}

.section-lead a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.section-title {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 10px;
}

.section-intro {
  font-size: 15px;
  color: var(--color-muted);
  line-height: 1.7;
  max-width: var(--reading);
  margin-bottom: 20px;
}

.section-intro a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.section-note {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.7;
  margin-top: 14px;
  max-width: var(--reading);
}

.section-note a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.sub-title {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 12px;
}

.table-scroll {
  width: 100%;
  overflow-x: auto;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
}

.data-table {
  width: 100%;
  min-width: 640px;
  font-size: 14px;
  line-height: 1.65;
}

.data-table th,
.data-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--color-line);
}

.data-table thead th {
  background: #F1ECE2;
  font-weight: 600;
  color: var(--color-ink);
  white-space: nowrap;
}

.data-table tbody th {
  font-weight: 600;
  color: var(--color-ink);
  white-space: nowrap;
}

.data-table tbody tr:last-child th,
.data-table tbody tr:last-child td {
  border-bottom: 0;
}

.data-table tbody tr:hover td,
.data-table tbody tr:hover th {
  background: #FBF8F2;
  box-shadow: inset 3px 0 0 var(--color-accent);
}

.boundary-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.boundary-list li {
  position: relative;
  padding-left: 18px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-ink);
}

.boundary-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 8px;
  height: 8px;
  background: var(--color-accent);
  border-radius: 2px;
}

.boundary-note {
  border: 1px solid var(--color-line);
  border-left: 4px solid var(--color-accent);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  padding: 20px 22px;
}

.boundary-note > p:last-child {
  margin-top: 14px;
  font-size: 14px;
  color: var(--color-muted);
}

.boundary-note .boundary-list li::before {
  background: var(--color-accent-2);
}

.boundary-note a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.btn {
  display: inline-block;
  padding: 11px 22px;
  font-size: 15px;
  line-height: 1.4;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease;
  min-height: 44px;
}

.btn-primary {
  background: var(--color-accent);
  color: #FFFFFF;
  border-color: var(--color-accent);
}

.btn-primary:hover {
  background: #9A4626;
  border-color: #9A4626;
  color: #FFFFFF;
}

.btn-ghost {
  background: transparent;
  color: var(--color-ink);
  border-color: var(--color-line);
}

.btn-ghost:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* ============ breadcrumb & page header ============ */

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 20px 0 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--color-muted);
}

.breadcrumb a {
  color: var(--color-muted);
}

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

.breadcrumb-sep {
  color: var(--color-line);
}

.breadcrumb-current {
  color: var(--color-ink);
  font-weight: 600;
}

.page-header {
  padding: 22px 0 30px;
  border-bottom: 1px solid var(--color-line);
  margin-bottom: 32px;
}

.page-title {
  font-size: 30px;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 12px;
}

.page-description {
  font-size: 16px;
  line-height: 1.75;
  color: var(--color-muted);
  max-width: var(--reading);
}

.page-description a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ============ index: clue bar ============ */

.clue-bar {
  background: var(--color-ink);
  color: #F2EDE4;
}

.clue-bar p {
  max-width: var(--container);
  margin: 0 auto;
  padding: 10px 24px;
  font-size: 14px;
  line-height: 1.6;
}

/* ============ index: hero ============ */

.hero {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-line);
}

.hero-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 44px 24px 36px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 40px;
  align-items: start;
}

.hero-copy {
  max-width: 560px;
}

.hero-title {
  font-size: 30px;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 16px;
}

.hero-lead {
  font-size: 16px;
  line-height: 1.75;
  color: var(--color-ink);
  margin-bottom: 12px;
}

.hero-note {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-muted);
  margin-bottom: 22px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.hero-media {
  min-width: 0;
}

.hero-figure {
  background: var(--color-bg);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.hero-figure img {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 10;
  object-fit: cover;
}

.hero-figure figcaption {
  padding: 0 16px 14px;
  margin-top: 12px;
}

.hero-cats {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px 40px;
}

.hero-cats-title {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 14px;
}

.cat-entry-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.cat-entry a {
  display: block;
  height: 100%;
  padding: 14px 16px;
  background: var(--color-bg);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  transition: border-color 0.15s ease, background-color 0.15s ease;
}

.cat-entry a:hover {
  border-color: var(--color-accent);
  background: #FBF6EE;
}

.cat-name {
  display: block;
  font-size: 15px;
  font-weight: 600;
  color: var(--color-ink);
  margin-bottom: 4px;
}

.cat-desc {
  display: block;
  font-size: 13px;
  line-height: 1.6;
  color: var(--color-muted);
}

/* ============ index: collection cards ============ */

.collection-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.collection-card {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.collection-card:hover {
  border-color: var(--color-accent-2);
  box-shadow: 0 2px 10px rgba(31, 29, 26, 0.06);
}

.collection-figure {
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-line);
}

.collection-figure img {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.collection-entry .collection-name,
.collection-entry .collection-idea,
.collection-entry .collection-meta {
  padding: 0 18px;
}

.collection-entry .collection-name {
  margin: 16px 0 8px;
}

.collection-entry .collection-idea {
  margin-bottom: 12px;
}

.collection-entry .collection-meta {
  padding-bottom: 18px;
}

.collection-name {
  font-size: 17px;
  font-weight: 600;
  line-height: 1.4;
}

.collection-idea {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-muted);
}

.collection-meta,
.collection-fields {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr);
  gap: 6px 12px;
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
}

.collection-meta dt,
.collection-fields dt {
  color: var(--color-muted);
}

.collection-meta dd,
.collection-fields dd {
  margin: 0;
  color: var(--color-ink);
}

/* ============ index: field & boundary ============ */

.field-boundary-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  gap: 28px;
  align-items: start;
}

.field-table-col {
  min-width: 0;
}

.boundary-col {
  min-width: 0;
}

/* ============ index: records brief ============ */

.records-groups {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.records-group {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 18px 20px;
}

.records-month {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-accent-2);
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--color-line);
}

.records-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.record-item {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: 4px 10px;
  font-size: 14px;
  line-height: 1.6;
}

.record-item time {
  color: var(--color-muted);
}

.record-type {
  display: inline-block;
  justify-self: start;
  font-size: 12px;
  line-height: 1.5;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  background: #EDE6DA;
  color: #7A4A2C;
}

.record-target {
  grid-column: 1 / -1;
  color: var(--color-ink);
}

/* ============ index: site index ============ */

.index-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 20px;
}

.index-col {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 18px 20px;
}

.index-col-title {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--color-line);
}

.index-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.index-list a {
  font-size: 14px;
  color: var(--color-muted);
  line-height: 1.6;
}

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

/* ============ categories page ============ */

.section-cat-table,
.section-cat-boundary,
.section-cat-relation,
.section-cat-next {
  padding-top: 0;
  margin-bottom: 40px;
}

.section-figure {
  margin-bottom: 20px;
}

.section-figure img {
  width: 100%;
  height: auto;
  aspect-ratio: 21 / 9;
  object-fit: cover;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
}

.boundary-block {
  border: 1px solid var(--color-line);
  border-left: 4px solid var(--color-accent);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  padding: 20px 22px;
}

.boundary-block .boundary-list li::before {
  background: var(--color-accent);
}

.relation-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.relation-item {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 18px 20px;
}

.relation-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--color-accent-2);
}

.relation-item p {
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-muted);
}

.section-cat-next p {
  font-size: 15px;
  line-height: 1.8;
  max-width: var(--reading);
}

.section-cat-next a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ============ collections page ============ */

.collection-list,
.collection-mapping,
.collection-append,
.related-links {
  padding-top: 0;
  margin-bottom: 40px;
}

.collection-list .collection-card {
  display: flex;
  flex-direction: column;
}

.collection-body {
  padding: 16px 18px 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.collection-body .collection-name {
  margin: 0;
}

.collection-body .collection-idea {
  margin: 0;
}

.collection-fields {
  margin-top: 2px;
}

.mapping-item {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 18px 20px;
  margin-bottom: 14px;
}

.mapping-item:last-child {
  margin-bottom: 0;
}

.mapping-item h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
}

.mapping-item p {
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-muted);
}

.collection-append p {
  font-size: 15px;
  line-height: 1.8;
  max-width: var(--reading);
}

.collection-append a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.append-note {
  margin-top: 12px;
  font-size: 14px;
  color: var(--color-muted);
}

.related-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.related-list a {
  display: block;
  padding: 14px 16px;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  font-size: 15px;
  color: var(--color-ink);
  transition: border-color 0.15s ease, color 0.15s ease;
}

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

/* ============ guide page ============ */

.guide-figure,
.field-meaning,
.browse-order,
.faq-section,
.boundary-note {
  padding-top: 0;
  margin-bottom: 40px;
}

.guide-figure h2,
.field-meaning h2,
.browse-order h2,
.faq-section h2,
.boundary-note h2 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 10px;
}

.media-figure {
  max-width: var(--reading);
}

.media-figure img {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
}

.field-table tbody th {
  width: 120px;
}

.step-list {
  counter-reset: step;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  max-width: var(--reading);
}

.step-item {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 18px 20px 18px 58px;
}

.step-item::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 18px;
  top: 18px;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--color-accent-2);
  color: #FFFFFF;
  font-size: 13px;
  font-weight: 600;
  line-height: 26px;
  text-align: center;
}

.step-item:last-child:nth-child(odd) {
  grid-column: 1 / -1;
}

.step-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 6px;
}

.step-item p {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-muted);
}

.prep-note {
  max-width: var(--reading);
  margin-top: 20px;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 18px 20px;
}

.prep-note h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 10px;
}

.plain-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.plain-list li {
  position: relative;
  padding-left: 16px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-muted);
}

.plain-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-accent-2);
}

.faq-list {
  max-width: var(--reading);
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.faq-item {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 0 18px;
}

.faq-item[open] {
  border-color: var(--color-accent-2);
}

.faq-question {
  cursor: pointer;
  list-style: none;
  font-size: 16px;
  font-weight: 600;
  line-height: 1.5;
  padding: 15px 28px 15px 0;
  position: relative;
}

.faq-question::-webkit-details-marker {
  display: none;
}

.faq-question::after {
  content: "+";
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  font-size: 18px;
  font-weight: 400;
  color: var(--color-accent);
  line-height: 1;
}

.faq-item[open] .faq-question::after {
  content: "−";
}

.faq-answer {
  padding: 0 0 16px;
  border-top: 1px solid var(--color-line);
  margin-top: 0;
}

.faq-answer p {
  font-size: 15px;
  line-height: 1.75;
  color: var(--color-muted);
  padding-top: 14px;
}

.feedback-entry {
  max-width: var(--reading);
  margin-top: 18px;
  font-size: 15px;
  line-height: 1.7;
}

.feedback-entry a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ============ records page ============ */

.lead-strip {
  background: var(--color-ink);
  color: #F2EDE4;
}

.lead-strip p {
  max-width: var(--container);
  margin: 0 auto;
  padding: 10px 24px;
  font-size: 14px;
  line-height: 1.6;
}

.records-intro,
.records-months,
.records-rules,
.records-usage {
  padding-top: 0;
  margin-bottom: 40px;
}

.records-intro h2,
.records-months h2,
.records-rules h2,
.records-usage h2 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 10px;
}

.records-figure {
  max-width: var(--reading);
  margin: 16px 0 20px;
}

.records-figure img {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
}

.records-intro p {
  font-size: 15px;
  line-height: 1.8;
  color: var(--color-muted);
  max-width: var(--reading);
  margin-bottom: 12px;
}

.records-months .records-group {
  margin-bottom: 20px;
  padding: 20px 22px;
}

.records-months .records-group:last-child {
  margin-bottom: 0;
}

.records-months .records-month {
  font-size: 17px;
  border-bottom: 1px solid var(--color-line);
}

.records-months .records-list {
  gap: 0;
}

.records-item {
  padding: 14px 0;
  border-bottom: 1px dashed var(--color-line);
}

.records-item:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.records-date {
  font-size: 13px;
  color: var(--color-muted);
  margin-bottom: 4px;
}

.records-type {
  display: inline-block;
  font-size: 12px;
  line-height: 1.5;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  background: #E4EDE8;
  color: #2F5344;
  margin-bottom: 6px;
}

.records-target {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-ink);
  margin-bottom: 4px;
}

.records-basis {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-muted);
  margin-bottom: 0;
}

.rules-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.rule-item {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 18px 20px;
}

.rule-item h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--color-accent-2);
}

.rule-item p {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-muted);
}

.records-usage p {
  font-size: 15px;
  line-height: 1.8;
  color: var(--color-muted);
  max-width: var(--reading);
  margin-bottom: 12px;
}

.records-usage a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ============ feedback page ============ */

.feedback-section {
  padding-top: 0;
  margin-bottom: 40px;
}

.feedback-section .section-title {
  margin-bottom: 10px;
}

.content-figure {
  max-width: var(--reading);
  margin: 0 0 22px;
}

.content-figure img {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
}

.feedback-type-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.feedback-type-item {
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 18px 20px;
}

.feedback-type-item .item-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 6px;
}

.feedback-type-item .item-desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-muted);
  margin-bottom: 0;
}

.feedback-excluded .boundary-note {
  max-width: var(--reading);
  padding-top: 20px;
  margin-bottom: 0;
}

.boundary-item .item-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--color-ink);
}

.boundary-item .item-desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-muted);
  margin-bottom: 0;
}

.feedback-excluded .boundary-list {
  gap: 16px;
}

.feedback-excluded .boundary-list li {
  padding-left: 18px;
}

.feedback-excluded .boundary-list li::before {
  top: 8px;
  background: var(--color-accent);
}

.feedback-step-list {
  counter-reset: fbstep;
  max-width: var(--reading);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.feedback-step-item {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: 18px 20px 18px 56px;
}

.feedback-step-item::before {
  counter-increment: fbstep;
  content: counter(fbstep);
  position: absolute;
  left: 18px;
  top: 18px;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--color-accent);
  color: #FFFFFF;
  font-size: 13px;
  font-weight: 600;
  line-height: 24px;
  text-align: center;
}

.feedback-step-item:last-child:nth-child(odd) {
  grid-column: 1 / -1;
}

.feedback-step-item .item-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 6px;
}

.feedback-step-item .item-desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-muted);
  margin-bottom: 0;
}

.related-link-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.related-link-item a {
  display: block;
  padding: 14px 16px;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  font-size: 15px;
  color: var(--color-ink);
  transition: border-color 0.15s ease, color 0.15s ease;
}

.related-link-item a:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* ============ 404 ============ */

.error-main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 60px 24px 72px;
  width: 100%;
}

.error-panel {
  max-width: var(--reading);
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  padding: 36px 32px;
}

.error-code {
  font-size: 14px;
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: 10px;
}

.error-panel h1 {
  font-size: 30px;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 14px;
}

.error-lead {
  font-size: 16px;
  line-height: 1.75;
  color: var(--color-muted);
  margin-bottom: 22px;
}

.error-entries {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-bottom: 22px;
}

.error-entries a {
  display: block;
  padding: 13px 16px;
  background: var(--color-bg);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  font-size: 15px;
  color: var(--color-ink);
  transition: border-color 0.15s ease, color 0.15s ease;
}

.error-entries a:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.error-action {
  margin-bottom: 14px;
}

.error-home-link {
  display: inline-block;
  padding: 11px 22px;
  min-height: 44px;
  background: var(--color-accent);
  color: #FFFFFF;
  border-radius: var(--radius-md);
  font-size: 15px;
  line-height: 1.4;
}

.error-home-link:hover {
  background: #9A4626;
  color: #FFFFFF;
}

.error-note {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-muted);
}

/* ============ responsive ============ */

@media (max-width: 1024px) {
  .hero-inner {
    gap: 28px;
  }

  .cat-entry-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .field-boundary-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 24px;
  }

  .records-groups {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .index-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .rules-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 768px) {
  .header-inner {
    padding: 0 18px;
    min-height: 60px;
    gap: 12px;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    flex: 0 0 auto;
  }

  .nav-list {
    display: none;
  }

  .nav-list.is-open {
    display: flex;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 50;
    background: var(--color-bg);
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    gap: 0;
    padding: 72px 24px 32px;
    overflow-y: auto;
  }

  .nav-list.is-open li {
    border-bottom: 1px solid var(--color-line);
  }

  .nav-list.is-open a {
    display: block;
    padding: 14px 0;
    min-height: 48px;
    font-size: 17px;
  }

  .nav-list.is-open a.is-current {
    border-bottom: 0;
    color: var(--color-accent);
  }

  .clue-bar p,
  .lead-strip p {
    padding: 10px 18px;
  }

  .section,
  .hero-inner,
  .hero-cats {
    padding-left: 18px;
    padding-right: 18px;
  }

  .inner-main {
    padding-left: 18px;
    padding-right: 18px;
  }

  .hero-inner {
    grid-template-columns: minmax(0, 1fr);
    padding-top: 30px;
    padding-bottom: 26px;
    gap: 24px;
  }

  .hero-copy {
    max-width: none;
  }

  .hero-title,
  .page-title,
  .error-panel h1 {
    font-size: 24px;
  }

  .hero-cats {
    padding-bottom: 30px;
  }

  .page-header {
    padding: 18px 0 22px;
    margin-bottom: 26px;
  }

  .section,
  .section-head,
  .collection-list,
  .collection-mapping,
  .collection-append,
  .related-links,
  .guide-figure,
  .field-meaning,
  .browse-order,
  .faq-section,
  .records-intro,
  .records-months,
  .records-rules,
  .records-usage,
  .feedback-section {
    margin-bottom: 30px;
  }

  .collection-grid,
  .relation-list,
  .related-list,
  .feedback-type-list,
  .feedback-step-list,
  .related-link-list,
  .error-entries,
  .step-list {
    grid-template-columns: minmax(0, 1fr);
  }

  .step-item:last-child:nth-child(odd),
  .feedback-step-item:last-child:nth-child(odd) {
    grid-column: auto;
  }

  .records-groups,
  .index-grid,
  .rules-list {
    grid-template-columns: minmax(0, 1fr);
  }

  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 24px;
    padding: 32px 18px 22px;
  }

  .footer-bottom p {
    padding-left: 18px;
    padding-right: 18px;
  }

  .error-panel {
    padding: 28px 22px;
  }

  .error-main {
    padding: 40px 18px 56px;
  }

  .data-table {
    min-width: 560px;
  }
}

@media (max-width: 480px) {
  .cat-entry-list {
    grid-template-columns: minmax(0, 1fr);
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .btn {
    text-align: center;
  }

  .collection-meta,
  .collection-fields {
    grid-template-columns: 76px minmax(0, 1fr);
  }

  .record-item {
    grid-template-columns: minmax(0, 1fr);
  }

  .record-target {
    grid-column: auto;
  }

  .section-head h2,
  .section-title,
  .guide-figure h2,
  .field-meaning h2,
  .browse-order h2,
  .faq-section h2,
  .boundary-note h2,
  .records-intro h2,
  .records-months h2,
  .records-rules h2,
  .records-usage h2 {
    font-size: 18px;
  }

  .data-table {
    min-width: 520px;
  }
}