:root {
  --bg: #ffffff;
  --ink: #1f2a24;
  --ink-soft: #4a5a51;
  --ink-faint: #6f7d75;
  --line: #e3e7e3;
  --line-strong: #ccd4cc;
  --moss: #4f7a52;
  --lake: #3f7c8c;
  --ochre: #b07a3c;
  --deep: #2f5d3a;
  --surface: #f6f8f5;
  --surface-alt: #eef3ee;
  --radius: 8px;
  --radius-sm: 6px;
  --shadow: 0 1px 2px rgba(31, 42, 36, 0.06), 0 8px 20px -14px rgba(31, 42, 36, 0.22);
  --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SFMono-Regular", "JetBrains Mono", "Roboto Mono", Menlo, Consolas, "Courier New", monospace;
  --wrap: 1140px;
  --wrap-narrow: 960px;
  --gutter: 24px;
}

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

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3,
h4,
p,
figure,
blockquote,
dl,
dd {
  margin: 0;
}

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

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

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

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

a:focus-visible,
button:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--lake);
  outline-offset: 2px;
}

button {
  font: inherit;
  color: inherit;
  cursor: pointer;
}

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

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 — 全站骨架
   ========================================================================== */

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: saturate(140%) blur(6px);
}

.header-inner {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 12px var(--gutter);
  display: flex;
  align-items: center;
  gap: 20px;
  min-height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
  color: var(--ink);
  font-weight: 700;
  letter-spacing: 0;
}

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

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 34px;
  height: 34px;
  padding: 0 8px;
  border-radius: var(--radius-sm);
  background: var(--deep);
  color: #ffffff;
  font-size: 15px;
  font-weight: 700;
  line-height: 1;
}

.brand-sub {
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
  white-space: nowrap;
}

.site-nav {
  margin-left: auto;
  position: relative;
}

.nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  padding: 0 12px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  background: #ffffff;
  color: var(--ink);
  font-size: 14px;
  font-weight: 600;
}

.nav-toggle::before {
  content: "";
  width: 16px;
  height: 2px;
  margin-right: 8px;
  background: currentColor;
  box-shadow: 0 -5px 0 currentColor, 0 5px 0 currentColor;
}

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

.nav-list li {
  display: block;
}

.nav-list a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 14px;
  border-radius: var(--radius-sm);
  color: var(--ink-soft);
  font-size: 15px;
  font-weight: 500;
  white-space: nowrap;
}

.nav-list a:hover {
  background: var(--surface-alt);
  color: var(--deep);
}

.nav-list a.is-current {
  color: var(--deep);
  font-weight: 700;
  background: var(--surface-alt);
}

.site-main {
  flex: 1 0 auto;
  width: 100%;
}

.inner-main {
  max-width: var(--wrap-narrow);
  margin: 0 auto;
  padding: 20px var(--gutter) 64px;
}

.section {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 56px var(--gutter);
  border-top: 1px solid var(--line);
}

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

.section-head {
  max-width: 760px;
  margin-bottom: 28px;
}

.section-title {
  font-size: 24px;
  line-height: 1.4;
  font-weight: 700;
  color: var(--ink);
}

.section-desc {
  margin-top: 10px;
  color: var(--ink-soft);
  font-size: 15.5px;
  line-height: 1.8;
}

.section-intro,
.section-lead {
  margin: 10px 0 24px;
  color: var(--ink-soft);
  font-size: 15.5px;
  line-height: 1.8;
}

.section-more {
  margin-top: 24px;
  font-size: 15px;
}

.section-more a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 0;
  font-weight: 600;
  border-bottom: 1px solid var(--line-strong);
}

.section-more a::after {
  content: "→";
  font-size: 14px;
}

.section-more a:hover {
  border-bottom-color: var(--moss);
}

/* ==========================================================================
   components — 按钮、面包屑、表格、列表基础件
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 22px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  font-size: 15.5px;
  font-weight: 600;
  line-height: 1;
  transition: background-color 0.18s ease, border-color 0.18s ease, color 0.18s ease;
}

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

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

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

.btn-ghost:hover {
  border-color: var(--moss);
  color: var(--deep);
  background: var(--surface-alt);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--ink-faint);
  padding: 4px 0 0;
}

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

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

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

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

.page-header {
  margin: 18px 0 8px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
}

.page-title {
  font-size: 28px;
  line-height: 1.35;
  font-weight: 700;
  color: var(--ink);
}

.page-description {
  margin-top: 12px;
  max-width: 720px;
  color: var(--ink-soft);
  font-size: 15.5px;
  line-height: 1.85;
}

.page-description a {
  border-bottom: 1px solid var(--line-strong);
}

.figure-reset,
.hero-figure,
.playlist-figure,
.playlist-cover,
.category-figure,
.boundary-figure,
.guide-figure,
.record-figure {
  margin: 0;
}

.hero-figure img,
.playlist-figure img,
.playlist-cover img,
.category-figure img,
.boundary-figure img,
.guide-figure img,
.record-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: var(--radius);
  background: var(--surface-alt);
}

.hero-figure figcaption,
.playlist-cover figcaption,
.boundary-figure figcaption,
.guide-figure figcaption,
.record-figure figcaption {
  margin-top: 10px;
  color: var(--ink-faint);
  font-size: 13.5px;
  line-height: 1.7;
}

.field-table {
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  font-size: 15px;
}

.field-table caption,
.field-table-caption,
.mapping-caption {
  text-align: left;
  padding: 14px 16px;
  background: var(--surface);
  border-bottom: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 14px;
  font-weight: 600;
}

.field-table th,
.field-table td {
  padding: 12px 16px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
  line-height: 1.75;
}

.field-table thead th {
  background: var(--surface-alt);
  color: var(--ink);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0;
}

.field-table tbody th {
  width: 32%;
  min-width: 132px;
  color: var(--deep);
  font-weight: 600;
  font-family: var(--font-mono);
  font-size: 14px;
  white-space: normal;
}

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

.boundary-list {
  display: grid;
  gap: 12px;
}

.boundary-item {
  position: relative;
  padding: 12px 16px 12px 34px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.75;
}

.boundary-item::before {
  content: "";
  position: absolute;
  left: 15px;
  top: 21px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--ochre);
}

.related-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.related-item {
  padding: 18px;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.related-item:hover {
  border-color: var(--line-strong);
  box-shadow: var(--shadow);
}

.related-item a {
  display: inline-block;
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

.related-item a:hover {
  color: var(--deep);
}

.related-item p {
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 14.5px;
  line-height: 1.75;
}

/* ==========================================================================
   pages — 首页
   ========================================================================== */

.home-main {
  display: block;
}

/* 首屏定位区 */
.hero {
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, #ffffff 0%, #f6f8f5 100%);
}

.hero-inner {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 48px var(--gutter) 52px;
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(300px, 0.85fr);
  gap: 44px;
  align-items: start;
}

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

.hero-eyebrow {
  display: inline-block;
  padding: 5px 12px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: #ffffff;
  color: var(--deep);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0;
}

.hero-title {
  margin-top: 18px;
  font-size: 34px;
  line-height: 1.32;
  font-weight: 700;
  color: var(--ink);
  max-width: 20em;
}

.hero-text {
  margin-top: 16px;
  max-width: 34em;
  color: var(--ink-soft);
  font-size: 16.5px;
  line-height: 1.85;
}

.hero-points {
  margin-top: 22px;
  display: grid;
  gap: 10px;
}

.hero-points li {
  position: relative;
  padding-left: 24px;
  color: var(--ink);
  font-size: 15.5px;
  line-height: 1.75;
}

.hero-points li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 11px;
  width: 10px;
  height: 2px;
  background: var(--moss);
}

.hero-actions {
  margin-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.hero-aside {
  display: grid;
  gap: 20px;
  min-width: 0;
}

.hero-figure {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  padding: 10px;
}

.hero-figure img {
  aspect-ratio: 16 / 10;
  height: auto;
}

.hero-quick {
  padding: 20px;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.hero-quick-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

.hero-quick-list {
  margin-top: 12px;
  display: grid;
  gap: 10px;
}

.hero-quick-list li {
  padding-left: 14px;
  border-left: 3px solid var(--lake);
  color: var(--ink-soft);
  font-size: 14.5px;
  line-height: 1.7;
}

.hero-quick-list li:nth-child(2) {
  border-left-color: var(--moss);
}

.hero-quick-list li:nth-child(3) {
  border-left-color: var(--ochre);
}

/* 题材分类索引 */
.category-list {
  display: grid;
  gap: 12px;
  counter-reset: none;
}

.category-row {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 20px;
  align-items: start;
  padding: 18px 20px;
  background: #ffffff;
  border: 1px solid var(--line);
  border-left: 4px solid var(--moss);
  border-radius: var(--radius);
  transition: border-color 0.18s ease, box-shadow 0.18s ease, background-color 0.18s ease;
}

.category-row:hover {
  background: var(--surface);
  box-shadow: var(--shadow);
}

.cat-tone-a {
  border-left-color: var(--moss);
}

.cat-tone-b {
  border-left-color: var(--lake);
}

.cat-tone-c {
  border-left-color: var(--ochre);
}

.cat-tone-d {
  border-left-color: var(--deep);
}

.cat-tone-e {
  border-left-color: #7a8f6a;
}

.category-code {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 34px;
  padding: 0 10px;
  border-radius: var(--radius-sm);
  background: var(--surface-alt);
  color: var(--deep);
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0;
}

.cat-tone-b .category-code {
  color: var(--lake);
}

.cat-tone-c .category-code {
  color: var(--ochre);
}

.category-body {
  min-width: 0;
}

.category-name {
  font-size: 18px;
  font-weight: 700;
  line-height: 1.5;
}

.category-name a {
  color: var(--ink);
}

.category-name a:hover {
  color: var(--deep);
}

.category-desc {
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.8;
}

.category-meta {
  margin-top: 8px;
  color: var(--ink-faint);
  font-size: 13.5px;
  font-variant-numeric: tabular-nums;
}

/* 专题片单入口 */
.playlist-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.playlist-card {
  display: flex;
  flex-direction: column;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

.playlist-card:hover {
  border-color: var(--line-strong);
  box-shadow: var(--shadow);
}

.playlist-figure,
.playlist-cover {
  border-bottom: 1px solid var(--line);
  background: var(--surface-alt);
}

.playlist-figure img,
.playlist-cover img {
  aspect-ratio: 16 / 9;
  height: auto;
  border-radius: 0;
}

.playlist-cover figcaption {
  margin: 0;
  padding: 10px 16px;
  background: #ffffff;
  border-bottom: 1px solid var(--line);
}

.playlist-body {
  padding: 18px 20px 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex: 1 1 auto;
}

.playlist-name {
  font-size: 17px;
  font-weight: 700;
  line-height: 1.5;
}

.playlist-name a {
  color: var(--ink);
}

.playlist-name a:hover {
  color: var(--deep);
}

.playlist-theme {
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.8;
}

.playlist-note {
  margin-top: auto;
  padding-top: 10px;
  border-top: 1px dashed var(--line);
  color: var(--ink-faint);
  font-size: 13.5px;
  line-height: 1.7;
}

/* 条目字段口径摘要 */
.fields-columns {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
  gap: 28px;
  align-items: start;
}

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

.fields-subtitle {
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 14px;
}

.fields-note {
  margin-top: 16px;
  color: var(--ink-soft);
  font-size: 14.5px;
  line-height: 1.8;
}

.fields-note a {
  border-bottom: 1px solid var(--line-strong);
}

/* 浏览顺序四步 */
.step-list {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.step-item {
  position: relative;
  padding: 20px 18px;
  background: #ffffff;
  border: 1px solid var(--line);
  border-top: 3px solid var(--moss);
  border-radius: var(--radius);
  min-width: 0;
}

.step-item:nth-child(2) {
  border-top-color: var(--lake);
}

.step-item:nth-child(3) {
  border-top-color: var(--ochre);
}

.step-item:nth-child(4) {
  border-top-color: var(--deep);
}

.step-index {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
}

.step-name {
  margin-top: 6px;
  font-size: 16.5px;
  font-weight: 700;
  color: var(--ink);
  line-height: 1.5;
}

.step-check {
  margin-top: 10px;
  color: var(--ink-soft);
  font-size: 14.5px;
  line-height: 1.8;
}

/* 整理记录速览 */
.record-groups {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.record-group {
  padding: 20px;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  min-width: 0;
}

.record-month {
  font-size: 16px;
  font-weight: 700;
  color: var(--deep);
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
  font-variant-numeric: tabular-nums;
}

.record-list {
  margin-top: 12px;
  display: grid;
  gap: 12px;
}

.record-list li {
  position: relative;
  padding-left: 16px;
  color: var(--ink-soft);
  font-size: 14.5px;
  line-height: 1.75;
}

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

.record-tag {
  display: inline-block;
  margin-top: 6px;
  padding: 2px 8px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: var(--surface);
  color: var(--ink-faint);
  font-size: 12.5px;
  line-height: 1.6;
}

/* 站内栏目索引 */
.index-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 16px;
}

.index-col {
  padding: 18px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  min-width: 0;
}

.index-name {
  font-size: 15.5px;
  font-weight: 700;
}

.index-name a {
  color: var(--ink);
}

.index-name a:hover {
  color: var(--deep);
}

.index-desc {
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.75;
}

/* ==========================================================================
   pages — 内页（题材分类 / 专题片单 / 浏览说明 / 整理记录）
   ========================================================================== */

/* 题材分类 */
.category-overview,
.category-fields-legend,
.category-boundary,
.category-order,
.category-related,
.playlist-entry,
.playlist-criteria,
.playlist-order,
.playlist-mapping,
.guide-steps,
.guide-checkpoints,
.guide-fields,
.guide-boundary,
.guide-faq,
.guide-links,
.record-months,
.record-scope,
.record-diff,
.record-reading,
.record-related {
  margin-top: 44px;
}

.category-overview .category-list {
  margin-top: 4px;
}

.category-overview .category-row {
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 22px;
  align-items: start;
  padding: 18px;
}

.category-figure {
  width: 100%;
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: var(--surface-alt);
}

.category-figure img {
  aspect-ratio: 4 / 3;
  height: auto;
  border-radius: 0;
}

.category-overview .category-code {
  margin-bottom: 10px;
}

.category-scope {
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.8;
}

.category-fields {
  margin-top: 12px;
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 6px 14px;
  padding: 12px 14px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
}

.category-fields dt {
  font-family: var(--font-mono);
  font-size: 13.5px;
  font-weight: 600;
  color: var(--deep);
}

.category-fields dd {
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.7;
}

.category-link {
  margin-top: 12px;
  font-size: 14.5px;
}

.category-link a {
  font-weight: 600;
  border-bottom: 1px solid var(--line-strong);
}

.boundary-figure {
  margin-bottom: 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px;
  background: #ffffff;
}

.boundary-figure img {
  aspect-ratio: 16 / 9;
  height: auto;
}

.order-steps {
  display: grid;
  gap: 14px;
}

.order-step {
  padding: 18px 20px;
  background: #ffffff;
  border: 1px solid var(--line);
  border-left: 4px solid var(--lake);
  border-radius: var(--radius);
  min-width: 0;
}

.order-step-name,
.order-name {
  font-size: 16.5px;
  font-weight: 700;
  color: var(--ink);
  line-height: 1.5;
}

.order-step-input,
.order-step-process,
.order-step-result,
.order-text {
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.8;
}

.order-step-input::before {
  content: "输入 · ";
  color: var(--ink-faint);
  font-weight: 600;
}

.order-step-process::before {
  content: "过程 · ";
  color: var(--ink-faint);
  font-weight: 600;
}

.order-step-result::before {
  content: "结果 · ";
  color: var(--ink-faint);
  font-weight: 600;
}

/* 专题片单 */
.playlist-entry .playlist-grid {
  margin-top: 4px;
}

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

.criteria-item {
  padding: 18px 20px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  min-width: 0;
}

.criteria-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--deep);
  line-height: 1.5;
}

.criteria-desc {
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.8;
}

.playlist-order .order-step {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 6px 16px;
  align-items: baseline;
  border-left-color: var(--moss);
}

.playlist-order .order-index {
  grid-row: span 2;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 32px;
  border-radius: var(--radius-sm);
  background: var(--surface-alt);
  color: var(--deep);
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.playlist-order .order-name {
  grid-column: 2;
}

.playlist-order .order-text {
  grid-column: 2;
  margin-top: 0;
}

.mapping-table {
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  font-size: 15px;
}

.mapping-table th,
.mapping-table td {
  padding: 12px 16px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
  line-height: 1.75;
}

.mapping-table thead th {
  background: var(--surface-alt);
  font-size: 14px;
  font-weight: 700;
}

.mapping-table tbody th {
  color: var(--deep);
  font-weight: 600;
  width: 34%;
}

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

.mapping-note {
  margin-top: 16px;
  color: var(--ink-soft);
  font-size: 14.5px;
  line-height: 1.8;
}

.mapping-note a {
  border-bottom: 1px solid var(--line-strong);
}

/* 浏览说明 */
.guide-steps .step-list {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.guide-steps .step-item {
  padding: 20px;
  border-top: 1px solid var(--line);
  border-left: 4px solid var(--moss);
}

.guide-steps .step-item:nth-child(2) {
  border-left-color: var(--lake);
}

.guide-steps .step-item:nth-child(3) {
  border-left-color: var(--ochre);
}

.guide-steps .step-item:nth-child(4) {
  border-left-color: var(--deep);
}

.step-input,
.step-process,
.step-result {
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.8;
}

.step-input::before {
  content: "输入 · ";
  color: var(--ink-faint);
  font-weight: 600;
}

.step-process::before {
  content: "过程 · ";
  color: var(--ink-faint);
  font-weight: 600;
}

.step-result::before {
  content: "结果 · ";
  color: var(--ink-faint);
  font-weight: 600;
}

.guide-figure {
  margin-top: 24px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px;
  background: #ffffff;
}

.guide-figure img {
  aspect-ratio: 16 / 9;
  height: auto;
}

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

.checkpoint-item {
  padding: 18px 20px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  min-width: 0;
}

.checkpoint-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
  line-height: 1.5;
}

.checkpoint-item p {
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.8;
}

.faq-item {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #ffffff;
  margin-bottom: 12px;
  overflow: hidden;
}

.faq-item summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 16px 18px;
  min-height: 44px;
  font-size: 16px;
  font-weight: 600;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
}

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

.faq-item summary::after {
  content: "+";
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--moss);
}

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

.faq-item summary:hover {
  background: var(--surface);
}

.faq-item p {
  padding: 0 18px 18px;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.85;
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

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

/* 整理记录 */
.record-figure {
  margin-top: 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 10px;
  background: #ffffff;
}

.record-figure img {
  aspect-ratio: 16 / 9;
  height: auto;
}

.record-months .record-month {
  padding: 0 0 20px;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
}

.record-month-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--ink);
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
  font-variant-numeric: tabular-nums;
}

.record-month-title time {
  color: var(--deep);
}

.record-months .record-list {
  margin-top: 14px;
}

.record-item {
  padding: 12px 14px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
}

.record-text {
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.8;
}

.record-item .record-tag {
  margin-top: 8px;
}

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

.scope-item {
  position: relative;
  padding: 14px 16px 14px 34px;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.8;
}

.scope-item::before {
  content: "";
  position: absolute;
  left: 15px;
  top: 22px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--lake);
}

.diff-table {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: #ffffff;
}

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

.diff-row + .diff-row {
  border-top: 1px solid var(--line);
}

.diff-head {
  background: var(--surface-alt);
}

.diff-cell {
  padding: 12px 16px;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink-soft);
  min-width: 0;
}

.diff-cell + .diff-cell {
  border-left: 1px solid var(--line);
}

.diff-head .diff-cell {
  font-size: 14px;
  font-weight: 700;
  color: var(--ink);
}

.diff-row:not(.diff-head) .diff-cell:first-child {
  color: var(--ink-faint);
}

.diff-row:not(.diff-head) .diff-cell:last-child {
  color: var(--ink);
}

.reading-steps {
  display: grid;
  gap: 14px;
}

.reading-step {
  padding: 18px 20px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-left: 4px solid var(--ochre);
  border-radius: var(--radius);
  min-width: 0;
}

.reading-step-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
  line-height: 1.5;
}

.reading-step-text {
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.8;
}

.related-links {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.related-links li {
  padding: 16px 18px;
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  min-width: 0;
}

.related-links li a {
  font-size: 15.5px;
  font-weight: 600;
  color: var(--ink);
}

.related-links li a:hover {
  color: var(--deep);
}

/* ==========================================================================
   pages — 404
   ========================================================================== */

.error-main {
  max-width: var(--wrap-narrow);
  margin: 0 auto;
  padding: 64px var(--gutter) 72px;
}

.error-block {
  padding: 40px 32px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-align: center;
}

.error-code {
  font-family: var(--font-mono);
  font-size: 44px;
  font-weight: 700;
  color: var(--moss);
  line-height: 1.1;
  font-variant-numeric: tabular-nums;
}

.error-block h1 {
  margin-top: 12px;
  font-size: 26px;
  font-weight: 700;
  color: var(--ink);
  line-height: 1.4;
}

.error-text {
  margin: 14px auto 0;
  max-width: 46em;
  color: var(--ink-soft);
  font-size: 16px;
  line-height: 1.85;
}

.error-actions {
  margin-top: 26px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}

.error-links {
  margin-top: 40px;
}

.error-links h2 {
  font-size: 20px;
  font-weight: 700;
  color: var(--ink);
}

.error-link-list {
  margin-top: 16px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.error-link-list li {
  background: #ffffff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  min-width: 0;
}

.error-link-list li a {
  display: block;
  padding: 14px 18px;
  min-height: 44px;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
}

.error-link-list li a:hover {
  color: var(--deep);
  background: var(--surface);
}

/* ==========================================================================
   layout — 页脚
   ========================================================================== */

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

.footer-inner {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 44px var(--gutter) 32px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 2.2fr);
  gap: 40px;
}

.footer-about {
  min-width: 0;
}

.footer-brand {
  font-size: 17px;
  font-weight: 700;
  color: var(--ink);
}

.footer-text {
  margin-top: 12px;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--ink-soft);
  max-width: 30em;
}

.footer-nav {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 24px;
}

.footer-group {
  min-width: 0;
}

.footer-group-title {
  font-size: 14.5px;
  font-weight: 700;
  color: var(--ink);
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line-strong);
}

.footer-group ul {
  margin-top: 12px;
  display: grid;
  gap: 8px;
}

.footer-group li a {
  display: inline-block;
  padding: 4px 0;
  min-height: 32px;
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.7;
}

.footer-group li a:hover {
  color: var(--deep);
}

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

.footer-copy {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 16px var(--gutter);
  color: var(--ink-faint);
  font-size: 13.5px;
  line-height: 1.7;
}

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

@media (max-width: 1024px) {
  .hero-inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
    padding: 40px var(--gutter) 44px;
  }

  .hero-title {
    font-size: 30px;
  }

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

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

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

  .fields-columns {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
  }

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

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

@media (max-width: 900px) {
  .category-overview .category-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 16px;
  }

  .category-figure img {
    aspect-ratio: 16 / 9;
  }
}

@media (max-width: 760px) {
  .header-inner {
    padding: 10px 18px;
    gap: 12px;
    min-height: 60px;
  }

  .brand-sub {
    font-size: 16px;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .nav-list {
    position: absolute;
    top: calc(100% + 10px);
    right: 0;
    min-width: 208px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    padding: 8px;
    background: #ffffff;
    border: 1px solid var(--line-strong);
    border-radius: var(--radius);
    box-shadow: 0 12px 28px -16px rgba(31, 42, 36, 0.35);
  }

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

  .nav-list a {
    justify-content: flex-start;
    width: 100%;
    padding: 0 12px;
  }

  .section {
    padding: 40px 18px;
  }

  .inner-main {
    padding: 16px 18px 52px;
  }

  .section-title {
    font-size: 21px;
  }

  .page-title {
    font-size: 23px;
  }

  .hero-inner {
    padding: 32px 18px 36px;
  }

  .hero-title {
    font-size: 26px;
  }

  .hero-text {
    font-size: 16px;
  }

  .hero-actions .btn {
    flex: 1 1 auto;
  }

  .category-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
    padding: 16px;
  }

  .category-code {
    justify-self: start;
  }

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

  .step-list,
  .guide-steps .step-list,
  .criteria-list,
  .checkpoint-list,
  .scope-list,
  .related-links,
  .record-groups,
  .index-grid,
  .error-link-list {
    grid-template-columns: minmax(0, 1fr);
  }

  .playlist-order .order-step {
    grid-template-columns: 44px minmax(0, 1fr);
    gap: 6px 12px;
  }

  .category-fields {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
  }

  .category-fields dd {
    margin-bottom: 8px;
  }

  .field-table tbody th {
    width: 38%;
    min-width: 0;
  }

  .field-table th,
  .field-table td,
  .mapping-table th,
  .mapping-table td {
    padding: 10px 12px;
  }

  .diff-cell {
    padding: 10px 12px;
    font-size: 14px;
  }

  .record-month-title {
    font-size: 17px;
  }

  .error-main {
    padding: 40px 18px 52px;
  }

  .error-block {
    padding: 32px 20px;
  }

  .error-code {
    font-size: 38px;
  }

  .footer-inner {
    padding: 36px 18px 26px;
  }

  .footer-copy {
    padding: 14px 18px;
  }
}

@media (max-width: 420px) {
  .brand-sub {
    font-size: 15px;
  }

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

  .page-title {
    font-size: 21px;
  }

  .section-title {
    font-size: 20px;
  }

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

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

  .hero-actions .btn {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .btn,
  .category-row,
  .playlist-card,
  .related-item {
    transition: none;
  }
}