:root {
  --paper: #fbfaf8;
  --card: #ffffff;
  --ink: #23262b;
  --muted: #5c636e;
  --line: #e4e2dd;
  --accent: #2f5d8a;
  --accent-soft: #eaf1f7;
  --tone-a: #3f7d6a;
  --tone-b: #8a5a3c;
  --tone-c: #6b5b95;
  --tone-d: #a9741f;
  --radius: 6px;
  --radius-sm: 4px;
  --shadow: 0 1px 2px rgba(35, 38, 43, 0.06);
  --shadow-hover: 0 6px 18px rgba(35, 38, 43, 0.1);
  --wrap: 1120px;
  --narrow: 720px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
}

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

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

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

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

h1,
h2,
h3,
h4 {
  margin: 0;
  font-weight: 600;
  line-height: 1.35;
  color: var(--ink);
}

p {
  margin: 0;
}

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

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

a:hover,
a:focus-visible {
  text-decoration: underline;
}

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

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

button {
  font: inherit;
  color: inherit;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.visually-hidden-title,
.visually-hidden-caption {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

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

.site-body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

.home-main,
.inner-main {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 20px 56px;
}

.inner-main {
  padding-top: 20px;
}

.section {
  padding: 32px 0;
  border-top: 1px solid var(--line);
}

.section:first-of-type {
  border-top: 0;
}

.section-head {
  margin-bottom: 18px;
}

.section-title,
.section-head h2 {
  font-size: 22px;
  margin-bottom: 8px;
}

.section-desc,
.section-note,
.section-intro {
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
  max-width: var(--narrow);
}

.section-foot {
  margin-top: 14px;
  font-size: 14px;
}

.inline-link {
  color: var(--accent);
  border-bottom: 1px solid rgba(47, 93, 138, 0.3);
  padding-bottom: 1px;
}

.inline-link:hover {
  border-bottom-color: var(--accent);
  text-decoration: none;
}

.block-title {
  font-size: 18px;
  margin-bottom: 6px;
}

.block-desc {
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 14px;
}

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

.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 40;
}

.header-inner {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 20px;
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 8px;
  color: var(--ink);
  text-decoration: none;
}

.brand:hover {
  text-decoration: none;
}

.brand-mark {
  font-size: 20px;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.brand-sub {
  font-size: 12px;
  color: var(--muted);
  letter-spacing: 0.04em;
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--card);
  cursor: pointer;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
}

.nav-toggle-bar {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--ink);
}

.site-nav {
  display: block;
}

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

.nav-list li {
  display: block;
}

.nav-list a {
  display: block;
  padding: 10px 12px;
  font-size: 15px;
  color: var(--ink);
  border-bottom: 2px solid transparent;
  text-decoration: none;
}

.nav-list a:hover {
  color: var(--accent);
  text-decoration: none;
}

.nav-list a.is-current {
  color: var(--accent);
  font-weight: 600;
  border-bottom-color: var(--accent);
}

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

.site-footer {
  background: var(--card);
  border-top: 1px solid var(--line);
  margin-top: 8px;
}

.footer-inner {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 32px 20px 20px;
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 28px;
}

.footer-brand-name {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 6px;
}

.footer-brand {
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
  max-width: 320px;
}

.footer-group-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 10px;
}

.footer-list li {
  margin-bottom: 6px;
}

.footer-list a {
  font-size: 14px;
  color: var(--muted);
  text-decoration: none;
}

.footer-list a:hover {
  color: var(--accent);
  text-decoration: none;
}

.footer-bottom {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 16px 20px 28px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  color: var(--muted);
  line-height: 1.7;
}

/* ============ tags / status ============ */

.tag {
  display: inline-block;
  padding: 1px 8px;
  font-size: 12px;
  line-height: 1.7;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  white-space: nowrap;
}

.tag--a,
.tag--green,
.tag-direction {
  color: var(--tone-a);
  background: rgba(63, 125, 106, 0.09);
  border-color: rgba(63, 125, 106, 0.28);
}

.tag--b,
.tag--brown {
  color: var(--tone-b);
  background: rgba(138, 90, 60, 0.09);
  border-color: rgba(138, 90, 60, 0.28);
}

.tag--c,
.tag--purple {
  color: var(--tone-c);
  background: rgba(107, 91, 149, 0.09);
  border-color: rgba(107, 91, 149, 0.28);
}

.tag--d,
.tag--amber {
  color: var(--tone-d);
  background: rgba(169, 116, 31, 0.1);
  border-color: rgba(169, 116, 31, 0.3);
}

.status {
  display: inline-block;
  padding: 1px 8px;
  font-size: 12px;
  line-height: 1.7;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line);
  color: var(--muted);
  background: #f6f5f2;
  white-space: nowrap;
}

.status--ongoing {
  color: var(--tone-a);
  background: rgba(63, 125, 106, 0.08);
  border-color: rgba(63, 125, 106, 0.26);
}

.status--done {
  color: var(--accent);
  background: rgba(47, 93, 138, 0.08);
  border-color: rgba(47, 93, 138, 0.26);
}

.status--paused {
  color: var(--tone-d);
  background: rgba(169, 116, 31, 0.09);
  border-color: rgba(169, 116, 31, 0.28);
}

/* ============ buttons ============ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 20px;
  font-size: 15px;
  border-radius: var(--radius);
  border: 1px solid transparent;
  text-decoration: none;
  transition: background-color 0.18s ease, border-color 0.18s ease, color 0.18s ease;
}

.btn:hover {
  text-decoration: none;
}

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

.btn-primary:hover {
  background: #27507a;
  border-color: #27507a;
  color: #ffffff;
}

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

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

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

.breadcrumb {
  font-size: 13px;
  color: var(--muted);
  padding: 4px 0 14px;
}

.breadcrumb a {
  color: var(--muted);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--accent);
  text-decoration: none;
}

.breadcrumb-sep {
  margin: 0 8px;
  color: #b6b2ab;
}

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

.page-header {
  padding: 0 0 22px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 26px;
}

.page-title {
  font-size: 30px;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 10px;
}

.page-description {
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted);
  max-width: var(--narrow);
}

.content-shell {
  width: 100%;
}

/* ============ index: fact bar ============ */

.fact-bar {
  background: #f4f2ee;
  border-bottom: 1px solid var(--line);
}

.fact-bar p {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 9px 20px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

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

.hero-index {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  gap: 36px;
  align-items: start;
  padding: 40px 0 36px;
}

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

.hero-title {
  font-size: 30px;
  font-weight: 600;
  line-height: 1.35;
  margin-bottom: 14px;
}

.hero-lead {
  font-size: 16px;
  line-height: 1.8;
  color: var(--muted);
  margin-bottom: 20px;
}

.hero-points {
  margin-bottom: 24px;
  border-top: 1px solid var(--line);
}

.hero-points li {
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

.hero-points strong {
  display: inline-block;
  min-width: 96px;
  color: var(--ink);
  font-weight: 600;
}

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

.hero-figure {
  margin: 0;
  min-width: 0;
}

.hero-figure img {
  width: 100%;
  height: auto;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: #efece7;
}

.hero-figure figcaption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

/* ============ index: topic overview ============ */

.topic-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.topic-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-top: 3px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 16px;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.topic-card--a {
  border-top-color: var(--tone-a);
}

.topic-card--b {
  border-top-color: var(--tone-b);
}

.topic-card--c {
  border-top-color: var(--tone-c);
}

.topic-card--d {
  border-top-color: var(--tone-d);
}

.topic-card .topic-name {
  font-size: 17px;
  margin-bottom: 8px;
}

.topic-card .topic-trait {
  font-size: 14px;
  line-height: 1.7;
  color: var(--ink);
  margin-bottom: 8px;
}

.topic-card .topic-scope {
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
  margin-bottom: 14px;
}

.topic-card .topic-link {
  margin-top: auto;
  font-size: 14px;
  color: var(--accent);
}

/* ============ index: cover wall ============ */

.cover-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.cover-item {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 12px;
  min-width: 0;
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.cover-item:hover {
  border-color: #cfd7e0;
  box-shadow: var(--shadow-hover);
}

.cover-figure {
  margin: 0 0 12px;
}

.cover-figure img {
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line);
  background: #efece7;
}

.cover-item .cover-name {
  font-size: 16px;
  margin-bottom: 8px;
}

.cover-item .cover-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--muted);
}

/* ============ index: update rows ============ */

.update-rows {
  border-top: 1px solid var(--line);
}

.update-rows .update-row {
  display: grid;
  grid-template-columns: 96px minmax(0, 1.1fr) auto minmax(0, 1.6fr);
  align-items: baseline;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}

.update-rows .update-date {
  font-size: 13px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum";
}

.update-rows .update-name {
  font-weight: 600;
  color: var(--ink);
}

.update-rows .update-note {
  color: var(--muted);
  line-height: 1.7;
}

/* ============ index: rank + feature ============ */

.rank-feature-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: 32px;
  align-items: start;
}

.rank-column,
.feature-column {
  min-width: 0;
}

.rank-list {
  border-top: 1px solid var(--line);
}

.rank-item {
  display: grid;
  grid-template-columns: 32px minmax(0, 1fr) auto;
  align-items: baseline;
  gap: 10px;
  padding: 11px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}

.rank-item .rank-no {
  font-size: 14px;
  font-weight: 600;
  color: var(--tone-b);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum";
}

.rank-item .rank-name {
  font-weight: 600;
  color: var(--ink);
}

.rank-item .rank-reason {
  grid-column: 2 / -1;
  font-size: 13px;
  color: var(--muted);
  line-height: 1.65;
}

.feature-cards {
  display: grid;
  gap: 12px;
}

.feature-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 3px solid var(--tone-c);
  border-radius: var(--radius);
  padding: 14px 16px;
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.feature-card:hover {
  border-color: #cfd7e0;
  border-left-color: var(--tone-c);
  box-shadow: var(--shadow-hover);
}

.feature-card .feature-name {
  font-size: 16px;
  margin-bottom: 6px;
}

.feature-card .feature-scope {
  font-size: 13px;
  color: var(--accent);
  margin-bottom: 6px;
}

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

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

.field-boundary-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: 32px;
  align-items: start;
}

.field-column,
.boundary-column {
  min-width: 0;
}

.field-table {
  font-size: 14px;
  border-top: 1px solid var(--line);
}

.field-table caption {
  text-align: left;
  font-size: 13px;
  color: var(--muted);
  padding-bottom: 8px;
}

.field-table th,
.field-table td {
  text-align: left;
  padding: 10px 12px 10px 0;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
  line-height: 1.7;
}

.field-table thead th {
  font-size: 13px;
  font-weight: 600;
  color: var(--muted);
  letter-spacing: 0.03em;
  background: #f6f5f2;
  padding-left: 10px;
}

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

.field-table td {
  color: var(--muted);
}

.notice-box {
  border: 1px solid rgba(169, 116, 31, 0.45);
  border-left-width: 3px;
  background: rgba(169, 116, 31, 0.06);
  border-radius: var(--radius);
  padding: 14px 16px;
  margin-bottom: 14px;
}

.notice-box p {
  font-size: 14px;
  line-height: 1.75;
  color: #6d4a12;
}

.boundary-text {
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

/* ============ index: column index ============ */

.column-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 14px;
}

.column-cell {
  display: block;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 14px;
  min-height: 88px;
  text-decoration: none;
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.column-cell:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-hover);
  text-decoration: none;
}

.column-cell .column-name {
  display: block;
  font-size: 16px;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 6px;
}

.column-cell .column-note {
  display: block;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
}

/* ============ topics page ============ */

.topic-groups {
  margin-bottom: 34px;
}

.topic-groups .section-title {
  font-size: 22px;
  margin-bottom: 8px;
}

.topic-block {
  display: grid;
  grid-template-columns: minmax(220px, 0.85fr) minmax(0, 1.6fr);
  gap: 26px;
  align-items: start;
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 3px solid var(--line);
  border-radius: var(--radius);
  padding: 22px 20px;
  margin-top: 18px;
}

.topic-block--green {
  border-left-color: var(--tone-a);
}

.topic-block--brown {
  border-left-color: var(--tone-b);
}

.topic-block--purple {
  border-left-color: var(--tone-c);
}

.topic-block--amber {
  border-left-color: var(--tone-d);
}

.topic-block-info {
  min-width: 0;
}

.topic-block-info .topic-name {
  font-size: 19px;
  margin-bottom: 10px;
}

.topic-block-info .topic-trait {
  font-size: 14px;
  line-height: 1.75;
  color: var(--ink);
  margin-bottom: 8px;
}

.topic-block-info .topic-scope {
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
  margin-bottom: 14px;
}

.topic-enter {
  display: inline-block;
  font-size: 14px;
  color: var(--accent);
  border-bottom: 1px solid rgba(47, 93, 138, 0.3);
}

.topic-enter:hover {
  text-decoration: none;
  border-bottom-color: var(--accent);
}

.topic-block-items {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  min-width: 0;
}

.entry-card {
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 10px;
  background: #fefdfc;
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.entry-card:hover {
  border-color: #cfd7e0;
  box-shadow: var(--shadow-hover);
}

.entry-cover {
  margin: 0 0 10px;
}

.entry-cover img {
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line);
  background: #efece7;
}

.entry-card .entry-name {
  font-size: 15px;
  margin-bottom: 6px;
}

.entry-card .entry-meta {
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
}

.topic-advice {
  border-top: 1px solid var(--line);
  padding-top: 28px;
}

.topic-advice .section-title {
  font-size: 22px;
  margin-bottom: 8px;
}

.advice-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 18px;
}

.advice-item {
  min-width: 0;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 16px;
}

.advice-item .advice-index {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.06em;
  margin-bottom: 8px;
  font-variant-numeric: tabular-nums;
}

.advice-item .advice-title {
  font-size: 16px;
  margin-bottom: 8px;
}

.advice-item .advice-text {
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

.advice-foot {
  margin-top: 16px;
  font-size: 14px;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
}

/* ============ updates page ============ */

.update-archive {
  border-top: 0;
  padding-top: 0;
}

.year-jump {
  margin-bottom: 16px;
}

.year-jump-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.year-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 8px 18px;
  font-size: 14px;
  color: var(--ink);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-decoration: none;
  font-variant-numeric: tabular-nums;
}

.year-link:hover {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

.year-link.is-active {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-soft);
  font-weight: 600;
}

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

.month-summary-item {
  min-width: 0;
}

.month-summary-link {
  display: block;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  text-decoration: none;
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.month-summary-link:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-hover);
  text-decoration: none;
}

.month-summary-name {
  display: block;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 4px;
  font-variant-numeric: tabular-nums;
}

.month-summary-meta {
  display: block;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
}

.month-group {
  scroll-margin-top: 80px;
}

.month-group .section-head h2 {
  font-size: 20px;
}

.month-group .update-list {
  border-top: 1px solid var(--line);
}

.month-group .update-row {
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.month-group .update-body {
  min-width: 0;
}

.month-group .update-row.is-featured {
  display: grid;
  grid-template-columns: 132px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
  background: #fdfcfb;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  margin-bottom: 14px;
}

.month-group .update-thumb {
  margin: 0;
}

.month-group .update-thumb img {
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line);
  background: #efece7;
}

.month-group .update-date {
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 4px;
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum";
}

.month-group .update-name {
  font-size: 16px;
  margin-bottom: 8px;
}

.month-group .update-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 8px;
}

.month-group .tag-status {
  color: var(--muted);
  background: #f6f5f2;
  border-color: var(--line);
}

.month-group .update-note {
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
  max-width: var(--narrow);
}

.update-fields .field-table {
  margin-top: 4px;
}

.update-fields .field-table th[scope="row"] {
  font-weight: 600;
  color: var(--ink);
  white-space: nowrap;
  padding-left: 0;
}

.related-entries .section-desc {
  margin-bottom: 4px;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  margin-top: 14px;
}

.related-item {
  min-width: 0;
}

.related-link {
  display: block;
  min-height: 44px;
  padding: 13px 15px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-decoration: none;
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.related-link:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-hover);
  text-decoration: none;
}

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

.related-desc {
  display: block;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
}

/* ============ ranking page ============ */

.ranking-section {
  border-top: 0;
  padding-top: 0;
}

.ranking-list {
  border-top: 1px solid var(--line);
}

.ranking-item {
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
  min-width: 0;
}

.ranking-item .ranking-rank {
  display: flex;
  align-items: baseline;
  gap: 8px;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 6px;
}

.ranking-item .rank-number {
  font-size: 20px;
  font-weight: 600;
  color: var(--tone-b);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum";
}

.ranking-item .ranking-name {
  font-size: 17px;
  margin-bottom: 8px;
}

.ranking-item .ranking-tag {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 8px;
}

.ranking-item .ranking-tag .tag {
  font-size: 12px;
}

.ranking-item .ranking-reason {
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
  max-width: var(--narrow);
}

.ranking-item.ranking-top {
  display: grid;
  grid-template-columns: 148px minmax(0, 1fr);
  gap: 20px;
  align-items: start;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
  margin-bottom: 14px;
}

.ranking-top .ranking-cover {
  margin: 0;
}

.ranking-top .ranking-cover img {
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border-radius: var(--radius-sm);
  border: 1px solid var(--line);
  background: #efece7;
}

.ranking-top .ranking-body {
  min-width: 0;
}

.ranking-method {
  border-top: 1px solid var(--line);
}

.method-columns {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 28px;
  align-items: start;
}

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

.method-col-title {
  font-size: 17px;
  margin-bottom: 8px;
}

.method-text {
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
  margin-bottom: 10px;
}

.method-fields {
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
  border-left: 2px solid var(--line);
  padding-left: 12px;
  margin-top: 12px;
}

.topic-links-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.topic-link-card {
  display: block;
  min-height: 88px;
  padding: 16px 14px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-decoration: none;
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.topic-link-card:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-hover);
  text-decoration: none;
}

.topic-link-name {
  display: block;
  font-size: 16px;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 6px;
}

.topic-link-note {
  display: block;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
}

.ranking-footnote {
  margin-top: 16px;
  font-size: 14px;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
}

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

.guide-section {
  padding: 0 0 34px;
  margin-bottom: 34px;
  border-bottom: 1px solid var(--line);
}

.guide-section:last-of-type {
  border-bottom: 0;
  margin-bottom: 0;
  padding-bottom: 8px;
}

.guide-section .section-title {
  font-size: 22px;
  margin-bottom: 10px;
}

.guide-figure {
  margin: 0 0 20px;
  max-width: 760px;
}

.guide-figure img {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: #efece7;
}

.guide-figure figcaption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.65;
  color: var(--muted);
}

.guide-section .field-table {
  max-width: 880px;
}

.guide-section .field-table .field-name {
  font-weight: 600;
  color: var(--ink);
  white-space: nowrap;
}

.guide-section .field-table td:last-child {
  color: var(--muted);
}

.boundary-block {
  max-width: 880px;
}

.boundary-note {
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
  margin-top: 10px;
}

.faq-list {
  max-width: 880px;
  border-top: 1px solid var(--line);
}

.faq-item {
  border-bottom: 1px solid var(--line);
}

.faq-question {
  cursor: pointer;
  padding: 14px 34px 14px 0;
  font-size: 16px;
  font-weight: 600;
  color: var(--ink);
  list-style: none;
  position: relative;
}

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

.faq-question::after {
  content: "＋";
  position: absolute;
  right: 6px;
  top: 13px;
  font-size: 15px;
  color: var(--muted);
}

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

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

.faq-answer {
  padding: 0 34px 16px 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
  max-width: var(--narrow);
}

.link-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  margin-top: 16px;
}

.link-grid-item {
  min-width: 0;
}

.link-grid-item a {
  display: block;
  min-height: 44px;
  padding: 14px 16px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  text-decoration: none;
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.link-grid-item a:hover {
  border-color: var(--accent);
  color: var(--accent);
  box-shadow: var(--shadow-hover);
  text-decoration: none;
}

.link-grid-desc {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  font-weight: 400;
  line-height: 1.65;
  color: var(--muted);
}

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

.error-main {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 56px 20px 64px;
  width: 100%;
}

.error-panel {
  max-width: 640px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 32px 28px;
}

.error-code {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--tone-d);
  margin-bottom: 10px;
  font-variant-numeric: tabular-nums;
}

.error-panel h1 {
  font-size: 26px;
  margin-bottom: 12px;
}

.error-desc {
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
  margin-bottom: 22px;
}

.error-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 28px;
}

.error-links {
  border-top: 1px solid var(--line);
  padding-top: 18px;
}

.error-links-title {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 10px;
}

.error-links-list li {
  margin-bottom: 6px;
}

.error-links-list a {
  font-size: 14px;
  color: var(--accent);
}

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

@media (max-width: 960px) {
  .header-inner {
    min-height: 60px;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    background: var(--card);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 8px 20px rgba(35, 38, 43, 0.08);
    padding: 8px 12px 14px;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nav-list.is-open {
    display: flex;
  }

  .nav-list a {
    min-height: 44px;
    display: flex;
    align-items: center;
    padding: 10px 8px;
    border-bottom: 1px solid var(--line);
  }

  .nav-list li:last-child a {
    border-bottom: 0;
  }

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

  .hero-index {
    grid-template-columns: minmax(0, 1fr);
    gap: 24px;
    padding: 28px 0 30px;
  }

  .hero-figure {
    order: 2;
  }

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

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

  .rank-feature-layout,
  .field-boundary-layout {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
  }

  .column-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .topic-block {
    grid-template-columns: minmax(0, 1fr);
    gap: 20px;
  }

  .topic-block-items {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .advice-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .related-grid,
  .topic-links-grid,
  .link-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .method-columns {
    grid-template-columns: minmax(0, 1fr);
    gap: 22px;
  }

  .footer-inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 24px;
  }

  .footer-brand {
    grid-column: 1 / -1;
  }
}

@media (max-width: 600px) {
  body {
    font-size: 15px;
  }

  .home-main,
  .inner-main {
    padding: 0 16px 44px;
  }

  .inner-main {
    padding-top: 16px;
  }

  .fact-bar p {
    padding: 8px 16px;
  }

  .header-inner {
    padding: 0 16px;
  }

  .brand-mark {
    font-size: 18px;
  }

  .brand-sub {
    display: none;
  }

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

  .section-title,
  .section-head h2,
  .topic-groups .section-title,
  .topic-advice .section-title,
  .guide-section .section-title {
    font-size: 19px;
  }

  .section {
    padding: 24px 0;
  }

  .hero-points strong {
    display: block;
    min-width: 0;
    margin-bottom: 2px;
  }

  .hero-actions .btn {
    flex: 1 1 100%;
  }

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

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

  .cover-item {
    padding: 10px;
  }

  .cover-item .cover-name {
    font-size: 15px;
  }

  .update-rows .update-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
    padding: 12px 0;
  }

  .update-rows .update-date {
    order: -1;
  }

  .rank-item {
    grid-template-columns: 28px minmax(0, 1fr);
    row-gap: 4px;
  }

  .rank-item .tag {
    grid-column: 2;
    justify-self: start;
  }

  .rank-item .rank-reason {
    grid-column: 2 / -1;
  }

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

  .topic-block {
    padding: 18px 16px;
  }

  .topic-block-items {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
  }

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

  .month-summary-list {
    grid-template-columns: minmax(0, 1fr);
  }

  .month-group .update-row.is-featured {
    grid-template-columns: 104px minmax(0, 1fr);
    gap: 14px;
    padding: 14px;
  }

  .ranking-item.ranking-top {
    grid-template-columns: 108px minmax(0, 1fr);
    gap: 14px;
    padding: 14px;
  }

  .ranking-item .rank-number {
    font-size: 18px;
  }

  .related-grid,
  .topic-links-grid,
  .link-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .field-table th,
  .field-table td {
    padding: 9px 8px 9px 0;
    font-size: 13px;
  }

  .field-table thead th {
    padding-left: 8px;
  }

  .field-table tbody th {
    white-space: normal;
  }

  .error-main {
    padding: 36px 16px 48px;
  }

  .error-panel {
    padding: 24px 18px;
  }

  .error-actions .btn {
    flex: 1 1 100%;
  }

  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
    padding: 26px 16px 16px;
    gap: 20px;
  }

  .footer-bottom {
    padding: 14px 16px 24px;
  }
}