/* ==========================================================================
   base — 全局基础样式
   ========================================================================== */

:root {
  --paper: #faf6ef;
  --ink: #1f2328;
  --accent: #8a2b2b;
  --blue: #37475a;
  --line: #e3dac9;
  --muted: #6b6f76;
  --white: #ffffff;
  --serif: Georgia, 'Times New Roman', 'Songti SC', 'SimSun', serif;
  --sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --container: 1080px;
  --header-h: 72px;
  --header-h-scrolled: 60px;
  --radius: 8px;
  --shadow-sm: 0 1px 3px rgba(31, 35, 40, 0.08);
  --shadow-md: 0 4px 12px rgba(31, 35, 40, 0.1);
  --transition: 0.25s ease;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--serif);
  font-size: 1rem;
  line-height: 1.8;
  color: var(--ink);
  background-color: var(--paper);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition), border-color var(--transition), background-color var(--transition);
}

a:hover {
  color: #6e1f1f;
}

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

p {
  margin-bottom: 1rem;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--serif);
  font-weight: 700;
  line-height: 1.4;
  color: var(--ink);
}

h1 {
  font-size: 2.25rem;
}

h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

h3 {
  font-size: 1.125rem;
  margin-bottom: 0.5rem;
}

ul,
ol {
  list-style-position: inside;
}

strong {
  font-weight: 700;
}

sup {
  font-size: 0.75em;
  line-height: 0;
  vertical-align: super;
  color: var(--accent);
}

/* ==========================================================================
   layout — 全站布局骨架
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--paper);
  border-bottom: 1px solid var(--line);
  transition: height var(--transition), box-shadow var(--transition);
  height: var(--header-h);
}

.site-header.is-scrolled {
  height: var(--header-h-scrolled);
  box-shadow: 0 2px 8px rgba(31, 35, 40, 0.06);
}

.header-shell {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand-link {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
  flex-shrink: 0;
}

.brand-name {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: 0.02em;
  transition: font-size var(--transition);
}

.site-header.is-scrolled .brand-name {
  font-size: 1.25rem;
}

.brand-tagline {
  font-size: 0.75rem;
  color: var(--muted);
  font-family: var(--sans);
}

.site-nav {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  list-style: none;
  gap: 28px;
  margin: 0;
  padding: 0;
}

.nav-list a {
  font-family: var(--sans);
  font-size: 0.9375rem;
  color: var(--ink);
  padding: 6px 0;
  position: relative;
  white-space: nowrap;
}

.nav-list a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent);
  transition: width var(--transition);
}

.nav-list a:hover::after,
.nav-list a:focus-visible::after,
.nav-list a.is-current::after {
  width: 100%;
}

.nav-list a.is-current {
  color: var(--accent);
  font-weight: 700;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  background: transparent;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  cursor: pointer;
  padding: 10px;
  flex-shrink: 0;
}

.nav-toggle-line {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--ink);
  transition: transform var(--transition), opacity var(--transition);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

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

.site-footer {
  background-color: var(--paper);
  border-top: 1px solid var(--line);
  margin-top: 60px;
  flex-shrink: 0;
}

.footer-shell {
  max-width: var(--container);
  margin: 0 auto;
  padding: 48px 24px 24px;
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr;
  gap: 48px;
}

.footer-col-title {
  font-family: var(--sans);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.footer-brand-name {
  font-size: 1.375rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.footer-brand-desc {
  font-size: 0.9375rem;
  color: var(--muted);
  line-height: 1.7;
}

.footer-nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

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

.footer-nav a {
  font-family: var(--sans);
  font-size: 0.9375rem;
  color: var(--ink);
}

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

.footer-note p {
  font-size: 0.875rem;
  color: var(--muted);
  line-height: 1.7;
}

.footer-bottom {
  border-top: 1px solid var(--line);
  padding: 16px 24px;
  text-align: center;
}

.footer-bottom p {
  font-size: 0.8125rem;
  color: var(--muted);
  font-family: var(--sans);
  margin: 0;
}

/* ==========================================================================
   components — 通用组件
   ========================================================================== */

.btn-primary,
.btn-secondary {
  display: inline-block;
  font-family: var(--sans);
  font-size: 0.9375rem;
  font-weight: 600;
  padding: 12px 28px;
  border-radius: var(--radius);
  border: 1px solid transparent;
  cursor: pointer;
  text-align: center;
  transition: background-color var(--transition), border-color var(--transition), color var(--transition), transform var(--transition);
}

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

.btn-primary:hover {
  background-color: #6e1f1f;
  border-color: #6e1f1f;
  color: var(--white);
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: transparent;
  color: var(--accent);
  border-color: var(--accent);
}

.btn-secondary:hover {
  background-color: var(--accent);
  color: var(--white);
}

.breadcrumb {
  max-width: var(--container);
  margin: 0 auto;
  padding: 24px 24px 0;
  font-family: var(--sans);
  font-size: 0.875rem;
  color: var(--muted);
}

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

.breadcrumb-sep {
  margin: 0 8px;
  color: var(--muted);
}

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

.page-header {
  max-width: var(--container);
  margin: 0 auto;
  padding: 32px 24px 40px;
}

.page-title {
  font-size: 2rem;
  color: var(--ink);
  margin-bottom: 12px;
}

.page-description {
  font-size: 1.0625rem;
  color: var(--muted);
  max-width: 720px;
  line-height: 1.8;
}

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

.inner-main .section-intro {
  color: var(--muted);
  margin-bottom: 24px;
  max-width: 720px;
}

figure {
  margin: 0;
}

figcaption {
  font-size: 0.8125rem;
  color: var(--muted);
  font-family: var(--sans);
  margin-top: 8px;
  text-align: center;
}

/* 条目编号 */
.item-number,
.service-number,
.method-index,
.step-number {
  font-family: var(--serif);
  font-weight: 700;
  color: var(--accent);
  flex-shrink: 0;
}

/* 脚注 */
.footnote-block {
  border-top: 1px solid var(--line);
  margin-top: 24px;
  padding-top: 16px;
}

.footnote-line {
  font-size: 0.875rem;
  color: var(--muted);
  margin-bottom: 4px;
  line-height: 1.6;
}

.footnote-line sup {
  margin-right: 4px;
}

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

.faq-item summary {
  font-family: var(--sans);
  font-size: 1rem;
  font-weight: 600;
  padding: 16px 8px;
  cursor: pointer;
  list-style-position: inside;
  transition: color var(--transition);
  user-select: none;
}

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

.faq-item summary::-webkit-details-marker {
  color: var(--accent);
}

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

.faq-item p {
  padding: 0 8px 16px;
  font-size: 0.9375rem;
  color: var(--muted);
  line-height: 1.8;
}

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

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

/* 双通道首屏 */
.hero-split {
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 48px;
  padding: 48px 0 56px;
  align-items: start;
}

.hero-intro {
  padding-right: 24px;
}

.hero-kicker {
  font-family: var(--sans);
  font-size: 0.8125rem;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 16px;
  font-weight: 600;
}

#hero-title {
  font-size: 2.75rem;
  line-height: 1.25;
  margin-bottom: 20px;
}

.hero-lead {
  font-size: 1.125rem;
  color: var(--muted);
  line-height: 1.8;
  margin-bottom: 28px;
  max-width: 540px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 32px;
}

.hero-figure {
  margin-top: 24px;
}

.hero-figure img {
  width: 100%;
  height: auto;
  max-height: 360px;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

.hero-quicklinks {
  background-color: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow-sm);
}

.quicklinks-title {
  font-size: 1.25rem;
  margin-bottom: 8px;
}

.quicklinks-note {
  font-size: 0.875rem;
  color: var(--muted);
  margin-bottom: 20px;
}

.quicklink-card {
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.quicklink-card:last-child {
  border-bottom: none;
}

.quicklink-card h3 {
  margin-bottom: 6px;
}

.quicklink-card h3 a {
  font-size: 1.0625rem;
  color: var(--ink);
}

.quicklink-card h3 a:hover {
  color: var(--accent);
}

.quicklink-card p {
  font-size: 0.875rem;
  color: var(--muted);
  margin-bottom: 0;
  line-height: 1.6;
}

/* 服务摘要区 */
.service-digest {
  padding: 48px 0;
  border-top: 1px solid var(--line);
}

.digest-box {
  background-color: var(--white);
  border-left: 4px solid var(--accent);
  padding: 24px 28px;
  margin-bottom: 32px;
  border-radius: 0 var(--radius) var(--radius) 0;
}

.digest-label {
  font-family: var(--sans);
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 8px;
}

.digest-quote {
  font-size: 1.25rem;
  font-style: italic;
  line-height: 1.7;
  color: var(--ink);
  margin: 0;
}

.digest-items {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.digest-item {
  background-color: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
  transition: background-color var(--transition), box-shadow var(--transition);
}

.digest-item:hover {
  background-color: #fdfbf7;
  box-shadow: var(--shadow-sm);
}

.digest-item .item-number {
  font-size: 1.5rem;
  display: block;
  margin-bottom: 12px;
}

.digest-item h3 {
  font-size: 1.0625rem;
  margin-bottom: 8px;
}

.digest-item p {
  font-size: 0.875rem;
  color: var(--muted);
  line-height: 1.7;
  margin-bottom: 0;
}

/* 工作准则摘录 */
.principles-excerpt {
  padding: 48px 0;
  border-top: 1px solid var(--line);
}

.section-note {
  font-size: 0.9375rem;
  color: var(--muted);
  margin-bottom: 24px;
  max-width: 720px;
}

.principle-list {
  list-style: none;
  padding: 0;
  margin: 0 0 24px;
}

.principle-item {
  padding: 20px 24px;
  border-bottom: 1px solid var(--line);
  transition: background-color var(--transition);
}

.principle-item:first-child {
  border-top: 1px solid var(--line);
}

.principle-item:hover {
  background-color: #fdfbf7;
}

.principle-item h3 {
  display: inline;
  font-size: 1.0625rem;
  margin-right: 8px;
}

.principle-item p {
  margin: 8px 0 0;
  font-size: 0.9375rem;
  color: var(--muted);
  line-height: 1.7;
}

.footnote-ref {
  font-size: 0.6875rem;
  color: var(--accent);
}

.section-link {
  margin-top: 16px;
}

.section-link a {
  font-family: var(--sans);
  font-size: 0.9375rem;
  font-weight: 600;
}

/* 服务过程示例 */
.process-example {
  padding: 48px 0;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  align-items: center;
}

.process-text h2 {
  margin-bottom: 16px;
}

.process-text p {
  color: var(--muted);
  line-height: 1.8;
}

.process-figure img {
  width: 100%;
  height: 280px;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

/* 公开资料入口 */
.resources-entry {
  padding: 48px 0;
  border-top: 1px solid var(--line);
}

.resource-columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  margin-top: 24px;
}

.resource-col {
  background-color: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
}

.resource-col h3 {
  font-size: 1.125rem;
  margin-bottom: 8px;
}

.resource-col p {
  font-size: 0.9375rem;
  color: var(--muted);
  line-height: 1.7;
  margin-bottom: 16px;
}

.resource-col a {
  font-family: var(--sans);
  font-size: 0.875rem;
  font-weight: 600;
}

/* 反馈与合作入口 */
.contact-entry {
  padding: 48px 0;
  border-top: 1px solid var(--line);
  text-align: left;
}

.contact-entry h2 {
  margin-bottom: 12px;
}

.contact-entry p {
  color: var(--muted);
  max-width: 640px;
  margin-bottom: 24px;
}

/* ==========================================================================
   pages — 内页
   ========================================================================== */

/* 机构说明页 */
.about-intro {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  padding: 24px 0 48px;
  align-items: start;
}

.intro-copy h2 {
  margin-bottom: 16px;
}

.intro-copy p {
  color: var(--muted);
  line-height: 1.8;
  margin-bottom: 1rem;
}

.intro-media img {
  width: 100%;
  height: 280px;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

.boundary-section,
.principles-section {
  padding: 40px 0;
  border-top: 1px solid var(--line);
}

.boundary-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.boundary-item {
  display: grid;
  grid-template-columns: 1fr;
  padding: 20px 24px;
  border-bottom: 1px solid var(--line);
  background-color: var(--white);
  border-radius: 0;
  transition: background-color var(--transition);
}

.boundary-item:first-child {
  border-top: 1px solid var(--line);
}

.boundary-item:hover {
  background-color: #fdfbf7;
}

.boundary-item h3 {
  font-size: 1rem;
  color: var(--accent);
  margin-bottom: 6px;
}

.boundary-item p {
  font-size: 0.9375rem;
  color: var(--muted);
  line-height: 1.7;
  margin-bottom: 0;
}

.principles-list {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: principle-counter;
}

.principles-list .principle-item {
  counter-increment: principle-counter;
  padding: 20px 24px;
  border-bottom: 1px solid var(--line);
  background-color: var(--white);
  margin-bottom: 0;
}

.principles-list .principle-item:first-child {
  border-top: 1px solid var(--line);
}

.principles-list .principle-item h3::before {
  content: counter(principle-counter) '. ';
  color: var(--accent);
  font-weight: 700;
  margin-right: 4px;
}

.principles-list .principle-item h3 {
  display: inline;
}

.principles-list .principle-item p {
  margin-top: 8px;
  color: var(--muted);
  font-size: 0.9375rem;
  line-height: 1.7;
}

/* 业务目录页 */
.services-list {
  padding: 24px 0 48px;
}

.service-item {
  display: grid;
  grid-template-columns: 64px 1fr;
  gap: 24px;
  padding: 32px 0;
  border-bottom: 1px solid var(--line);
  align-items: start;
}

.service-item:first-child {
  border-top: 1px solid var(--line);
}

.service-number {
  font-size: 2rem;
  line-height: 1;
  padding-top: 4px;
}

.service-content h3 {
  font-size: 1.25rem;
  margin-bottom: 8px;
}

.service-content > p {
  color: var(--muted);
  line-height: 1.8;
  margin-bottom: 16px;
}

.service-meta {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 16px;
}

.service-meta p {
  font-size: 0.875rem;
  color: var(--ink);
  background-color: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 12px 16px;
  line-height: 1.6;
  margin: 0;
}

.service-meta strong {
  display: block;
  color: var(--accent);
  font-size: 0.8125rem;
  font-family: var(--sans);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 4px;
}

.service-figure {
  grid-column: 2;
}

.service-figure img {
  width: 100%;
  max-height: 240px;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

.excluded-services,
.service-example,
.cooperation-guide {
  padding: 40px 0;
  border-top: 1px solid var(--line);
}

.excluded-list {
  list-style: none;
  padding: 0;
  margin: 16px 0;
}

.excluded-list li {
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.9375rem;
  color: var(--muted);
  position: relative;
  padding-left: 28px;
}

.excluded-list li::before {
  content: '×';
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
  font-size: 1.125rem;
}

.boundary-note {
  font-size: 0.875rem;
  color: var(--muted);
  font-style: italic;
  margin-top: 16px;
}

.service-example p,
.cooperation-guide p {
  color: var(--muted);
  line-height: 1.8;
  max-width: 780px;
}

.cooperation-guide a {
  font-family: var(--sans);
  font-weight: 600;
}

/* 工作准则页 */
.process-section {
  padding: 24px 0 48px;
}

.process-layout {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  align-items: start;
}

.process-content h2,
.criteria-section h2,
.delivery-section h2,
.faq-section h2 {
  margin-bottom: 16px;
}

.process-steps {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: step-counter;
}

.process-step {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 16px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
  counter-increment: step-counter;
}

.process-step:first-child {
  border-top: 1px solid var(--line);
}

.process-step .step-number {
  font-size: 1.5rem;
  line-height: 1;
  color: var(--accent);
}

.process-step .step-number::after {
  content: counter(step-counter);
}

.step-body h3 {
  font-size: 1.0625rem;
  margin-bottom: 6px;
}

.step-body p {
  font-size: 0.9375rem;
  color: var(--muted);
  line-height: 1.7;
  margin: 0;
}

.process-figure img {
  width: 100%;
  height: 320px;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

.criteria-section,
.delivery-section,
.faq-section {
  padding: 40px 0;
  border-top: 1px solid var(--line);
}

.criteria-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.criteria-item {
  padding: 20px 24px;
  border-bottom: 1px solid var(--line);
  background-color: var(--white);
}

.criteria-item:first-child {
  border-top: 1px solid var(--line);
}

.criteria-item h3 {
  font-size: 1rem;
  color: var(--accent);
  margin-bottom: 6px;
}

.criteria-item p {
  font-size: 0.9375rem;
  color: var(--muted);
  line-height: 1.7;
  margin: 0;
}

.delivery-list {
  list-style: none;
  padding: 0;
  margin: 16px 0 24px;
}

.delivery-list li {
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.9375rem;
  color: var(--muted);
  position: relative;
  padding-left: 24px;
}

.delivery-list li::before {
  content: '—';
  position: absolute;
  left: 0;
  color: var(--accent);
}

.faq-list {
  margin-top: 16px;
}

/* 公开资料页 */
.resources-index,
.glossary-section,
.usage-note {
  padding: 24px 0 48px;
}

.resources-index:first-of-type {
  padding-top: 0;
}

.section-heading h2 {
  margin-bottom: 8px;
}

.section-heading p {
  color: var(--muted);
  font-size: 0.9375rem;
  margin-bottom: 24px;
}

.resources-layout {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  align-items: start;
}

.resources-list {
  display: grid;
  gap: 16px;
}

.resource-item {
  background-color: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px 24px;
  transition: background-color var(--transition), box-shadow var(--transition);
}

.resource-item:hover {
  background-color: #fdfbf7;
  box-shadow: var(--shadow-sm);
}

.resource-item h3 {
  font-size: 1.0625rem;
  color: var(--accent);
  margin-bottom: 6px;
}

.resource-item p {
  font-size: 0.875rem;
  color: var(--muted);
  line-height: 1.7;
  margin: 0;
}

.resources-figure img {
  width: 100%;
  height: 320px;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

.glossary-list {
  margin: 0;
  padding: 0;
}

.glossary-item {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 24px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.glossary-item dt {
  font-weight: 700;
  color: var(--accent);
  font-size: 1rem;
}

.glossary-item dd {
  color: var(--muted);
  font-size: 0.9375rem;
  line-height: 1.7;
  margin: 0;
}

.usage-content p {
  color: var(--muted);
  line-height: 1.8;
  max-width: 780px;
}

/* 合作通道页 */
.content-section {
  padding: 24px 0 48px;
}

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

.method-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 16px;
}

.method-item {
  background-color: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
  transition: background-color var(--transition), box-shadow var(--transition);
}

.method-item:hover {
  background-color: #fdfbf7;
  box-shadow: var(--shadow-sm);
}

.method-index {
  font-size: 1.5rem;
  display: block;
  margin-bottom: 12px;
}

.method-item h3 {
  font-size: 1.0625rem;
  margin-bottom: 8px;
}

.method-item p {
  font-size: 0.875rem;
  color: var(--muted);
  line-height: 1.7;
  margin: 0;
}

.join-process .process-layout {
  margin-top: 16px;
}

.step-list {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: join-step-counter;
}

.step-list li {
  counter-increment: join-step-counter;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
  position: relative;
  padding-left: 56px;
}

.step-list li::before {
  content: counter(join-step-counter);
  position: absolute;
  left: 0;
  top: 16px;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--blue);
  color: var(--white);
  border-radius: 50%;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1rem;
}

.step-list h3 {
  font-size: 1rem;
  margin-bottom: 4px;
}

.step-list p {
  font-size: 0.875rem;
  color: var(--muted);
  line-height: 1.7;
  margin: 0;
}

.process-figure img {
  width: 100%;
  height: 320px;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

.check-list {
  list-style: none;
  padding: 0;
  margin: 16px 0 0;
}

.check-list li {
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.9375rem;
  color: var(--muted);
  position: relative;
  padding-left: 32px;
}

.check-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
}

.feedback-guide p {
  color: var(--muted);
  line-height: 1.8;
  max-width: 780px;
}

/* 404 页 */
.error-main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 80px 24px;
  flex: 1 0 auto;
}

.error-panel {
  max-width: 640px;
  margin: 0 auto;
  text-align: center;
  background-color: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 56px 40px;
  box-shadow: var(--shadow-sm);
}

.error-panel h1 {
  font-size: 4rem;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 16px;
}

.error-lead {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.error-desc {
  font-size: 0.9375rem;
  color: var(--muted);
  margin-bottom: 32px;
}

.error-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 16px;
  margin-bottom: 24px;
}

.error-footnote {
  font-size: 0.8125rem;
  color: var(--muted);
  font-style: italic;
  margin: 0;
}

/* ==========================================================================
   responsive — 响应式
   ========================================================================== */

@media (max-width: 960px) {
  .hero-split {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .hero-intro {
    padding-right: 0;
  }

  .digest-items {
    grid-template-columns: 1fr;
  }

  .process-example {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .resource-columns {
    grid-template-columns: 1fr;
  }

  .about-intro {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .service-meta {
    grid-template-columns: 1fr;
  }

  .process-layout {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .resources-layout {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .method-list {
    grid-template-columns: 1fr;
  }

  .footer-shell {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }

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

@media (max-width: 720px) {
  :root {
    --header-h: 64px;
    --header-h-scrolled: 56px;
  }

  .header-shell {
    padding: 0 16px;
    gap: 16px;
  }

  .brand-tagline {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    top: var(--header-h);
    left: 0;
    width: 100%;
    background-color: var(--paper);
    border-bottom: 1px solid var(--line);
    box-shadow: var(--shadow-md);
    display: block;
    visibility: visible;
    opacity: 1;
  }

  .site-header.is-scrolled .site-nav {
    top: var(--header-h-scrolled);
  }

  .nav-list {
    display: none;
    flex-direction: column;
    padding: 16px;
    gap: 0;
  }

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

  .nav-list li {
    width: 100%;
  }

  .nav-list a {
    display: block;
    padding: 14px 8px;
    font-size: 1rem;
    border-bottom: 1px solid var(--line);
    white-space: normal;
  }

  .nav-list a::after {
    display: none;
  }

  .nav-list a.is-current {
    background-color: rgba(138, 43, 43, 0.06);
  }

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

  .page-header {
    padding: 24px 16px 32px;
  }

  .breadcrumb {
    padding: 16px 16px 0;
  }

  h1 {
    font-size: 1.75rem;
  }

  #hero-title {
    font-size: 2rem;
  }

  .hero-split {
    padding: 32px 0 40px;
  }

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

  .hero-actions .btn-primary,
  .hero-actions .btn-secondary {
    text-align: center;
  }

  .hero-figure img {
    max-height: 240px;
  }

  .hero-quicklinks {
    padding: 20px;
  }

  .service-digest,
  .principles-excerpt,
  .process-example,
  .resources-entry,
  .contact-entry {
    padding: 32px 0;
  }

  .digest-box {
    padding: 20px;
  }

  .principle-item {
    padding: 16px;
  }

  .process-text p {
    font-size: 0.9375rem;
  }

  .process-figure img {
    height: 220px;
  }

  .resource-col {
    padding: 20px;
  }

  .contact-entry .btn-primary {
    width: 100%;
    text-align: center;
  }

  .footer-shell {
    grid-template-columns: 1fr;
    gap: 24px;
    padding: 32px 16px 16px;
  }

  .footer-brand {
    grid-column: auto;
  }

  .footer-bottom {
    padding: 12px 16px;
  }

  .about-intro {
    padding: 16px 0 32px;
  }

  .intro-media img {
    height: 220px;
  }

  .boundary-section,
  .principles-section {
    padding: 32px 0;
  }

  .boundary-item,
  .principles-list .principle-item {
    padding: 16px;
  }

  .service-item {
    grid-template-columns: 40px 1fr;
    gap: 16px;
    padding: 24px 0;
  }

  .service-number {
    font-size: 1.5rem;
  }

  .service-figure {
    grid-column: 1 / -1;
  }

  .excluded-services,
  .service-example,
  .cooperation-guide {
    padding: 32px 0;
  }

  .criteria-section,
  .delivery-section,
  .faq-section {
    padding: 32px 0;
  }

  .criteria-item {
    padding: 16px;
  }

  .process-step {
    grid-template-columns: 36px 1fr;
    gap: 12px;
  }

  .process-step .step-number {
    font-size: 1.25rem;
  }

  .glossary-item {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .step-list li {
    padding-left: 48px;
  }

  .step-list li::before {
    width: 32px;
    height: 32px;
    font-size: 0.875rem;
    top: 14px;
  }

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

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

  .error-panel h1 {
    font-size: 3rem;
  }

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

  .error-actions .btn-primary,
  .error-actions .btn-secondary {
    text-align: center;
  }
}

@media (max-width: 480px) {
  html {
    font-size: 15px;
  }

  .brand-name {
    font-size: 1.25rem;
  }

  .site-header.is-scrolled .brand-name {
    font-size: 1.125rem;
  }

  .nav-list a {
    font-size: 0.9375rem;
    padding: 12px 8px;
  }

  .digest-item,
  .method-item,
  .resource-col,
  .resource-item {
    padding: 16px;
  }

  .service-meta {
    grid-template-columns: 1fr;
  }

  .faq-item summary {
    font-size: 0.9375rem;
    padding: 14px 4px;
  }

  .faq-item p {
    padding: 0 4px 12px;
  }

  .footer-nav a {
    font-size: 0.875rem;
  }
}