/* ==========================================================================
   飘花飘雪电影 · 全站样式
   基础层 / 布局层 / 组件层 / 页面层 / 响应式
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. base — 变量、重置、排版、通用元素
   -------------------------------------------------------------------------- */

:root {
  --c-page: #ffffff;
  --c-soft: #f4f7f9;
  --c-ink: #0f2b3a;
  --c-ink-2: #4a6675;
  --c-accent: #1f8a8c;
  --c-accent-2: #2f6fb0;
  --c-line: #d8e3e8;
  --c-warn: #f0b429;
  --c-warn-soft: #fdf5e2;
  --c-accent-soft: #eaf4f4;
  --c-blue-soft: #eef3f9;
  --radius: 6px;
  --shadow-soft: 0 1px 2px rgba(15, 43, 58, 0.06);
  --w-wide: 1180px;
  --w-read: 760px;
  --gap: 24px;
}

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

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

body {
  margin: 0;
  background: var(--c-page);
  color: var(--c-ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  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(--c-ink);
}

p {
  margin: 0;
}

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

dl,
dd,
dt,
figure,
figcaption {
  margin: 0;
}

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

a {
  color: var(--c-accent);
  text-decoration: none;
  transition: color 0.18s ease, border-color 0.18s ease;
}

a:hover,
a:focus-visible {
  color: var(--c-accent-2);
}

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

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

th,
td {
  text-align: left;
}

strong {
  font-weight: 600;
  color: var(--c-ink);
}

/* 数字与字段名等宽对齐，便于逐行对照 */
.channel-code,
.channel-meta,
.step-num,
.step-no,
.log-meta dd,
.field-table td,
.data-table td {
  font-variant-numeric: tabular-nums;
}

/* --------------------------------------------------------------------------
   2. layout — 骨架：body、页头、主导航、主容器、面包屑、页标题、页脚
   -------------------------------------------------------------------------- */

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid var(--c-line);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 20px;
  width: 100%;
  max-width: var(--w-wide);
  margin: 0 auto;
  padding: 12px 24px;
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 10px;
  flex: 0 0 auto;
  color: var(--c-ink);
}

.brand:hover,
.brand:focus-visible {
  color: var(--c-accent);
}

.brand-mark {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: 0;
}

.brand-sub {
  font-size: 12px;
  color: var(--c-ink-2);
  border-left: 1px solid var(--c-line);
  padding-left: 10px;
}

.nav-toggle {
  display: none;
  margin-left: auto;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-page);
  color: var(--c-ink);
  cursor: pointer;
  position: relative;
}

.nav-toggle::before,
.nav-toggle::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  height: 2px;
  background: currentColor;
}

.nav-toggle::before {
  top: 16px;
  box-shadow: 0 6px 0 currentColor;
}

.nav-toggle::after {
  bottom: 16px;
}

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

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

.nav-list li {
  display: block;
}

.nav-list a {
  display: block;
  padding: 8px 14px;
  min-height: 40px;
  line-height: 24px;
  font-size: 15px;
  color: var(--c-ink-2);
  border: 1px solid transparent;
  border-radius: var(--radius);
}

.nav-list a:hover,
.nav-list a:focus-visible {
  color: var(--c-ink);
  border-color: var(--c-line);
  background: var(--c-soft);
}

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

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

.inner-main {
  max-width: var(--w-wide);
  margin: 0 auto;
  padding: 20px 24px 56px;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  font-size: 13px;
  color: var(--c-ink-2);
  padding: 4px 0 14px;
}

.breadcrumb a {
  color: var(--c-ink-2);
}

.breadcrumb a:hover,
.breadcrumb a:focus-visible {
  color: var(--c-accent);
}

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

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

.page-header {
  max-width: var(--w-read);
  padding: 0 0 24px;
  border-bottom: 1px solid var(--c-line);
  margin-bottom: 32px;
}

.page-title {
  font-size: 32px;
  font-weight: 600;
  color: var(--c-ink);
}

.page-description {
  margin-top: 12px;
  font-size: 15px;
  color: var(--c-ink-2);
}

.page-layout {
  display: block;
}

.content-column {
  max-width: var(--w-read);
}

/* 页脚 */
.site-footer {
  background: var(--c-soft);
  border-top: 1px solid var(--c-line);
  color: var(--c-ink-2);
}

.footer-inner {
  display: grid;
  grid-template-columns: 1.4fr repeat(3, 1fr);
  gap: 32px;
  max-width: var(--w-wide);
  margin: 0 auto;
  padding: 40px 24px 28px;
}

.footer-brand {
  max-width: 320px;
}

.footer-name {
  font-size: 16px;
  font-weight: 600;
  color: var(--c-ink);
}

.footer-desc {
  margin-top: 10px;
  font-size: 13.5px;
  line-height: 1.7;
}

.footer-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--c-ink);
  margin-bottom: 12px;
}

.footer-col ul {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.footer-col a {
  display: inline-block;
  padding: 2px 0;
  font-size: 14px;
  color: var(--c-ink-2);
}

.footer-col a:hover,
.footer-col a:focus-visible {
  color: var(--c-accent);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  justify-content: space-between;
  max-width: var(--w-wide);
  margin: 0 auto;
  padding: 14px 24px 22px;
  border-top: 1px solid var(--c-line);
  font-size: 13px;
}

.footer-note a {
  color: var(--c-ink-2);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.footer-note a:hover,
.footer-note a:focus-visible {
  color: var(--c-accent);
}

/* --------------------------------------------------------------------------
   3. components — 通用组件：区块、区块头、按钮、卡片、表格、步骤、提示
   -------------------------------------------------------------------------- */

.section {
  padding: 44px 0;
  border-top: 1px solid var(--c-line);
}

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

.section-head {
  max-width: var(--w-read);
  margin-bottom: 26px;
}

.section-head h2 {
  font-size: 22px;
}

.section-head p {
  margin-top: 10px;
  font-size: 15px;
  color: var(--c-ink-2);
}

.section-head p a {
  color: var(--c-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.section-intro,
.section-lead {
  max-width: var(--w-read);
  margin: 10px 0 22px;
  font-size: 15px;
  color: var(--c-ink-2);
}

.section-lead a {
  color: var(--c-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.section h2 {
  font-size: 22px;
}

.section h3 {
  font-size: 17px;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 20px;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 600;
  border: 1px solid transparent;
}

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

.btn-primary:hover,
.btn-primary:focus-visible {
  background: #1a7678;
  border-color: #1a7678;
  color: #ffffff;
}

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

.btn-ghost:hover,
.btn-ghost:focus-visible {
  border-color: var(--c-accent);
  color: var(--c-accent);
}

/* 图片容器统一约束 */
.hero-media,
.topic-media,
.topic-figure,
.channel-figure,
.section-media,
.boundary-figure {
  overflow: hidden;
  border-radius: var(--radius);
  background: var(--c-soft);
}

.hero-media img,
.topic-media img,
.topic-figure img,
.channel-figure img,
.section-media img,
.boundary-figure img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

figcaption {
  font-size: 13px;
  color: var(--c-ink-2);
  line-height: 1.6;
}

/* 表格 */
.field-table,
.data-table {
  width: 100%;
  font-size: 14.5px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-page);
}

.field-table caption,
.data-table caption {
  caption-side: top;
  text-align: left;
  padding: 0 0 10px;
  font-size: 13.5px;
  color: var(--c-ink-2);
}

.field-table th,
.field-table td,
.data-table th,
.data-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--c-line);
  vertical-align: top;
  line-height: 1.65;
}

.field-table thead th,
.data-table thead th {
  background: var(--c-soft);
  font-size: 13.5px;
  font-weight: 600;
  color: var(--c-ink);
  position: sticky;
  top: 0;
  z-index: 1;
}

.field-table tbody th,
.data-table tbody th {
  width: 22%;
  font-weight: 600;
  color: var(--c-ink);
  background: #fafcfd;
}

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

.field-table-wrap {
  overflow-x: auto;
}

/* 步骤条 */
.step-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 18px;
}

.step-item {
  padding: 18px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-page);
}

.step-item:hover {
  border-color: var(--c-accent);
}

.step-num,
.step-no {
  display: inline-block;
  min-width: 30px;
  padding: 2px 8px;
  margin-bottom: 10px;
  font-size: 13px;
  font-weight: 600;
  color: var(--c-accent);
  background: var(--c-accent-soft);
  border-radius: 4px;
}

.step-name {
  font-size: 16px;
}

.step-desc {
  margin-top: 8px;
  font-size: 14.5px;
  color: var(--c-ink-2);
}

.step-check {
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px dashed var(--c-line);
  font-size: 13.5px;
  color: var(--c-ink-2);
}

/* FAQ 折叠 */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  max-width: var(--w-read);
}

.faq-item {
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-page);
}

.faq-item summary {
  padding: 13px 16px;
  font-size: 15px;
  font-weight: 600;
  color: var(--c-ink);
  cursor: pointer;
  list-style: none;
}

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

.faq-item summary::after {
  content: "＋";
  float: right;
  color: var(--c-accent);
  font-weight: 600;
}

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

.faq-item summary:hover {
  color: var(--c-accent);
}

.faq-item p {
  padding: 0 16px 15px;
  font-size: 14.5px;
  color: var(--c-ink-2);
}

/* 相关入口链接行 */
.related-links,
.link-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.link-row a,
.related-links a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 10px 16px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-page);
  color: var(--c-ink);
  font-size: 14.5px;
}

.link-row a:hover,
.link-row a:focus-visible,
.related-links a:hover,
.related-links a:focus-visible {
  border-color: var(--c-accent);
  color: var(--c-accent);
  background: var(--c-accent-soft);
}

/* --------------------------------------------------------------------------
   4. pages — 首页与各内页业务模块
   -------------------------------------------------------------------------- */

/* 4.1 首页 */
.site-notice {
  background: var(--c-soft);
  border-bottom: 1px solid var(--c-line);
}

.site-notice p {
  max-width: var(--w-wide);
  margin: 0 auto;
  padding: 8px 24px;
  font-size: 13.5px;
  color: var(--c-ink-2);
}

.home-main {
  max-width: var(--w-wide);
  margin: 0 auto;
  padding: 0 24px 56px;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 40px;
  align-items: start;
  padding: 44px 0 48px;
}

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

.hero-eyebrow {
  font-size: 13.5px;
  color: var(--c-accent);
  font-weight: 600;
}

.hero-title {
  margin-top: 12px;
  font-size: 32px;
  font-weight: 600;
}

.hero-lead {
  margin-top: 16px;
  max-width: 34em;
  font-size: 16px;
  color: var(--c-ink-2);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.hero-facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 28px;
  padding-top: 20px;
  border-top: 1px solid var(--c-line);
}

.hero-fact dt {
  font-size: 13px;
  color: var(--c-ink-2);
}

.hero-fact dd {
  margin-top: 4px;
  font-size: 15px;
  font-weight: 600;
  color: var(--c-ink);
}

.hero-media {
  margin: 0;
  aspect-ratio: 4 / 3;
}

.hero-media figcaption {
  padding: 10px 2px 0;
}

/* 频道分类总览（首页） */
.channel-overview {
  display: flex;
  flex-direction: column;
  border-top: 1px solid var(--c-line);
}

.channel-row {
  display: grid;
  grid-template-columns: 76px minmax(0, 1fr) auto;
  gap: 20px;
  align-items: start;
  padding: 18px 4px;
  border-bottom: 1px solid var(--c-line);
}

.channel-row:hover {
  background: var(--c-soft);
}

.channel-code {
  font-size: 13.5px;
  font-weight: 600;
  color: var(--c-accent);
  padding-top: 2px;
}

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

.channel-name {
  font-size: 17px;
}

.channel-desc {
  margin-top: 6px;
  font-size: 14.5px;
  color: var(--c-ink-2);
}

.channel-meta {
  margin-top: 8px;
  font-size: 13.5px;
  color: var(--c-ink-2);
}

.channel-link {
  align-self: center;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  padding: 8px 16px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  font-size: 14px;
  color: var(--c-ink);
  white-space: nowrap;
}

.channel-link:hover,
.channel-link:focus-visible {
  border-color: var(--c-accent);
  color: var(--c-accent);
  background: var(--c-accent-soft);
}

/* 专题片单（首页 + 专题页共用卡片） */
.topic-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
}

.topic-card {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-page);
  overflow: hidden;
}

.topic-card:hover {
  border-color: var(--c-accent);
}

.topic-media,
.topic-figure {
  aspect-ratio: 16 / 9;
  border-radius: 0;
}

.topic-body {
  display: flex;
  flex-direction: column;
  flex: 1 1 auto;
  padding: 18px;
}

.topic-name {
  font-size: 17px;
}

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

.topic-name a:hover,
.topic-name a:focus-visible {
  color: var(--c-accent);
}

.topic-desc {
  margin-top: 8px;
  font-size: 14.5px;
  color: var(--c-ink-2);
}

.topic-basis {
  margin-top: 10px;
  font-size: 13.5px;
  color: var(--c-ink-2);
}

.topic-link {
  margin-top: auto;
  padding-top: 14px;
  font-size: 14px;
  font-weight: 600;
  color: var(--c-accent);
}

.topic-link:hover,
.topic-link:focus-visible {
  color: var(--c-accent-2);
}

.topic-meta {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 12px;
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--c-line);
  font-size: 13.5px;
}

.topic-meta dt {
  color: var(--c-ink-2);
}

.topic-meta dd {
  color: var(--c-ink);
}

/* 字段口径与收录边界摘要（首页） */
.fields-layout {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 28px;
}

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

.fields-subtitle {
  font-size: 16px;
  margin-bottom: 14px;
}

.fields-note {
  margin-top: 12px;
  font-size: 13.5px;
  color: var(--c-ink-2);
}

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

.boundary-list li {
  position: relative;
  padding: 10px 14px 10px 34px;
  border: 1px solid var(--c-line);
  border-left: 3px solid var(--c-warn);
  border-radius: var(--radius);
  background: var(--c-warn-soft);
  font-size: 14px;
  color: var(--c-ink);
}

.boundary-list li::before {
  content: "限";
  position: absolute;
  left: 12px;
  top: 10px;
  font-size: 12px;
  font-weight: 600;
  color: #a97a06;
}

/* 整理记录速览（首页） */
.record-groups {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
}

.record-group {
  padding: 18px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-soft);
}

.record-stage {
  font-size: 16px;
}

.record-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 12px;
}

.record-list li {
  font-size: 14px;
  color: var(--c-ink-2);
}

.record-tags {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--c-line);
  font-size: 13px;
  color: var(--c-ink-2);
}

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

.index-item {
  padding: 16px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-page);
}

.index-item:hover {
  border-color: var(--c-accent);
}

.index-item a {
  display: inline-block;
  min-height: 28px;
  font-size: 15px;
  font-weight: 600;
  color: var(--c-ink);
}

.index-item a:hover,
.index-item a:focus-visible {
  color: var(--c-accent);
}

.index-item p {
  margin-top: 8px;
  font-size: 13.5px;
  color: var(--c-ink-2);
}

/* 4.2 频道分类页 */
.channel-index {
  margin-bottom: 44px;
}

.channel-list {
  display: flex;
  flex-direction: column;
  border-top: 1px solid var(--c-line);
}

.channel-list .channel-row {
  grid-template-columns: 200px minmax(0, 1fr);
  gap: 24px;
  align-items: start;
  padding: 20px 4px;
}

.channel-figure {
  aspect-ratio: 4 / 3;
}

.channel-list .channel-code {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 4px;
  background: var(--c-accent-soft);
  font-size: 13px;
}

.channel-list .channel-meta {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 12px;
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px dashed var(--c-line);
}

.channel-list .channel-meta dt {
  color: var(--c-ink-2);
}

.channel-list .channel-meta dd {
  color: var(--c-ink);
}

.field-table {
  margin-top: 8px;
}

/* 4.3 专题片单页 */
.section-topic-rule {
  border-top: 1px solid var(--c-line);
}

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

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

.rule-col h3 {
  font-size: 16px;
  margin-bottom: 14px;
}

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

.criteria-list li {
  padding: 12px 14px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-soft);
  font-size: 14px;
  color: var(--c-ink-2);
}

.criteria-list strong {
  display: block;
  margin-bottom: 4px;
  color: var(--c-ink);
}

.order-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  counter-reset: order;
}

.order-list li {
  position: relative;
  padding: 12px 14px 12px 44px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  font-size: 14px;
  color: var(--c-ink-2);
  counter-increment: order;
}

.order-list li::before {
  content: counter(order, decimal-leading-zero);
  position: absolute;
  left: 14px;
  top: 12px;
  font-size: 13px;
  font-weight: 600;
  color: var(--c-accent);
}

.order-list strong {
  display: block;
  margin-bottom: 4px;
  color: var(--c-ink);
}

.order-note {
  margin-top: 14px;
  font-size: 13.5px;
  color: var(--c-ink-2);
}

.order-note a {
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* 4.4 浏览指引页 */
.section-steps,
.section-reading,
.section-faq,
.section-related {
  padding: 32px 0;
  border-top: 1px solid var(--c-line);
}

.section-steps:first-child {
  border-top: 0;
  padding-top: 0;
}

.section-reading h2,
.section-faq h2,
.section-related h2,
.section-steps h2 {
  font-size: 22px;
  margin-bottom: 6px;
}

.section-media {
  margin: 18px 0 22px;
  aspect-ratio: 16 / 9;
  max-width: var(--w-read);
}

.section-media figcaption {
  padding: 10px 2px 0;
}

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

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

.reading-col h3 {
  font-size: 16px;
  margin-bottom: 12px;
}

.field-reading {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.field-reading dt {
  font-size: 14px;
  font-weight: 600;
  color: var(--c-ink);
}

.field-reading dd {
  font-size: 14px;
  color: var(--c-ink-2);
  padding-left: 14px;
  border-left: 2px solid var(--c-line);
}

.filter-notes {
  margin-top: 14px;
  font-size: 13.5px;
  color: var(--c-ink-2);
}

/* 4.5 收录边界页 */
.boundary-intro {
  padding-bottom: 32px;
  border-bottom: 1px solid var(--c-line);
}

.boundary-intro h2 {
  font-size: 22px;
  margin-bottom: 16px;
}

.boundary-figure {
  margin: 0 0 20px;
  max-width: var(--w-read);
  aspect-ratio: 16 / 9;
}

.boundary-figure figcaption {
  padding: 10px 2px 0;
}

.boundary-intro p {
  max-width: var(--w-read);
  margin-bottom: 12px;
  font-size: 15px;
  color: var(--c-ink-2);
}

.boundary-intro p a {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.boundary-scope,
.boundary-rules,
.boundary-log,
.related-links {
  padding: 32px 0;
  border-bottom: 1px solid var(--c-line);
}

.boundary-scope h2,
.boundary-rules h2,
.boundary-log h2,
.related-links h2 {
  font-size: 22px;
  margin-bottom: 6px;
}

.scope-columns {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 28px;
  margin-top: 18px;
}

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

.scope-col h3 {
  font-size: 16px;
  margin-bottom: 14px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--c-line);
}

.scope-include h3 {
  border-bottom-color: var(--c-accent);
}

.scope-exclude h3 {
  border-bottom-color: var(--c-warn);
}

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

.scope-list li {
  padding: 10px 14px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  font-size: 14px;
  color: var(--c-ink-2);
}

.scope-include .scope-list li {
  background: var(--c-accent-soft);
}

.scope-exclude .scope-list li {
  background: var(--c-warn-soft);
}

.scope-list strong {
  display: block;
  margin-bottom: 3px;
  color: var(--c-ink);
}

.scope-note {
  margin-top: 18px;
  max-width: var(--w-read);
  font-size: 13.5px;
  color: var(--c-ink-2);
}

.rule-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-top: 18px;
}

.rule-item {
  padding: 16px 18px;
  border: 1px solid var(--c-line);
  border-left: 3px solid var(--c-accent);
  border-radius: var(--radius);
  background: var(--c-page);
}

.rule-item h3 {
  font-size: 16px;
}

.rule-item p {
  margin-top: 6px;
  font-size: 14.5px;
  color: var(--c-ink-2);
}

.log-groups {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
  margin-top: 18px;
}

.log-group {
  padding: 18px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-soft);
}

.log-group h3 {
  font-size: 16px;
}

.log-meta {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 12px;
  margin-top: 12px;
  padding: 10px 0;
  border-top: 1px solid var(--c-line);
  border-bottom: 1px solid var(--c-line);
  font-size: 13.5px;
}

.log-meta dt {
  color: var(--c-ink-2);
}

.log-meta dd {
  color: var(--c-ink);
}

.log-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 12px;
}

.log-list li {
  font-size: 14px;
  color: var(--c-ink-2);
}

/* 4.6 404 */
.error-main {
  max-width: var(--w-read);
  margin: 0 auto;
  padding: 56px 24px 64px;
}

.error-hero {
  padding-bottom: 32px;
  border-bottom: 1px solid var(--c-line);
}

.error-code {
  font-size: 40px;
  font-weight: 600;
  color: var(--c-accent);
  line-height: 1.2;
}

.error-hero h1 {
  margin-top: 10px;
  font-size: 26px;
}

.error-lead {
  margin-top: 14px;
  font-size: 15px;
  color: var(--c-ink-2);
}

.error-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.error-paths {
  padding-top: 32px;
}

.error-paths h2 {
  font-size: 20px;
}

.error-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 16px;
}

.error-list li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 12px;
  padding: 12px 14px;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  background: var(--c-soft);
}

.error-list a {
  font-size: 15px;
  font-weight: 600;
  color: var(--c-ink);
}

.error-list a:hover,
.error-list a:focus-visible {
  color: var(--c-accent);
}

.error-list span {
  font-size: 13.5px;
  color: var(--c-ink-2);
}

/* --------------------------------------------------------------------------
   5. responsive — 900px / 640px 断点
   -------------------------------------------------------------------------- */

@media (max-width: 900px) {
  .header-inner {
    flex-wrap: wrap;
    padding: 12px 20px;
  }

  .nav-toggle {
    display: block;
  }

  .site-nav {
    flex: 1 0 100%;
    margin-left: 0;
  }

  .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    padding: 10px 0 4px;
    border-top: 1px solid var(--c-line);
  }

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

  .nav-list a {
    padding: 11px 12px;
    border-color: var(--c-line);
  }

  .hero {
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
    padding: 32px 0 36px;
  }

  .hero-media {
    aspect-ratio: 16 / 10;
  }

  .footer-inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 28px;
    padding: 32px 20px 24px;
  }

  .footer-brand {
    grid-column: 1 / -1;
    max-width: none;
  }

  .footer-bottom {
    padding: 14px 20px 20px;
  }

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

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

  .channel-list .channel-row {
    grid-template-columns: 160px minmax(0, 1fr);
    gap: 18px;
  }
}

@media (max-width: 640px) {
  body {
    font-size: 15.5px;
  }

  .site-notice p {
    padding: 8px 16px;
  }

  .home-main,
  .inner-main {
    padding-left: 16px;
    padding-right: 16px;
  }

  .inner-main {
    padding-bottom: 40px;
  }

  .brand-sub {
    display: none;
  }

  .page-header {
    padding-bottom: 18px;
    margin-bottom: 24px;
  }

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

  .section h2,
  .section-head h2,
  .section-reading h2,
  .section-faq h2,
  .section-related h2,
  .section-steps h2,
  .boundary-intro h2,
  .boundary-scope h2,
  .boundary-rules h2,
  .boundary-log h2,
  .related-links h2 {
    font-size: 19px;
  }

  .section {
    padding: 32px 0;
  }

  .hero-facts {
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
  }

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

  .channel-overview .channel-row,
  .channel-list .channel-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 10px;
    padding: 16px 2px;
  }

  .channel-list .channel-figure {
    aspect-ratio: 16 / 9;
  }

  .channel-link {
    justify-self: start;
  }

  .topic-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 18px;
  }

  .fields-layout,
  .rule-columns,
  .reading-columns,
  .scope-columns {
    grid-template-columns: minmax(0, 1fr);
    gap: 22px;
  }

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

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

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

  .field-table,
  .data-table {
    font-size: 14px;
  }

  .field-table th,
  .field-table td,
  .data-table th,
  .data-table td {
    padding: 9px 10px;
  }

  .field-table tbody th,
  .data-table tbody th {
    width: 30%;
  }

  .field-table thead th,
  .data-table thead th {
    position: static;
  }

  .link-row a,
  .related-links a {
    flex: 1 1 100%;
    justify-content: center;
  }

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

  .footer-bottom {
    flex-direction: column;
    gap: 6px;
  }

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

  .error-code {
    font-size: 32px;
  }

  .error-hero h1 {
    font-size: 22px;
  }
}