:root {
  --paper: #f7f3ec;
  --ink: #2c2622;
  --ink-soft: #5a5148;
  --accent: #8a5a2b;
  --accent-deep: #6d4520;
  --rational: #4a5a4e;
  --line: #d8cec0;
  --card: #fffdf9;
  --radius: 6px;
  --container: 1080px;
  --serif: "Songti SC", "SimSun", "STSong", "Noto Serif SC", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

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

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

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

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

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

a:hover,
a:focus-visible {
  color: var(--accent-deep);
  text-decoration: underline;
}

h1,
h2,
h3 {
  font-family: var(--serif);
  color: var(--ink);
  line-height: 1.35;
  margin: 0 0 12px;
  letter-spacing: normal;
}

p {
  margin: 0 0 16px;
}

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

figure {
  margin: 0;
}

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

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

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

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

.header-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-family: var(--serif);
  font-size: 19px;
  font-weight: 700;
  flex: 0 0 auto;
}

.brand:hover {
  color: var(--accent-deep);
  text-decoration: none;
}

.brand-mark {
  width: 26px;
  height: 26px;
  border: 2px solid var(--accent);
  border-radius: var(--radius);
  display: inline-block;
  position: relative;
  flex: 0 0 auto;
}

.brand-mark::after {
  content: "";
  position: absolute;
  inset: 5px;
  background: var(--rational);
  border-radius: 2px;
}

.brand-name {
  white-space: nowrap;
}

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

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

.nav-link {
  display: block;
  padding: 8px 12px;
  color: var(--ink-soft);
  font-size: 15px;
  border-bottom: 2px solid transparent;
  min-height: 44px;
  line-height: 28px;
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--accent-deep);
  border-bottom-color: var(--line);
  text-decoration: none;
}

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

.nav-toggle {
  display: none;
  margin-left: auto;
  width: 44px;
  height: 44px;
  padding: 10px 8px;
  background: transparent;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  cursor: pointer;
  flex-direction: column;
  justify-content: space-between;
}

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

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

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

.site-footer {
  background: #efe8dd;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 14px;
}

.footer-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 36px 24px 24px;
  display: grid;
  grid-template-columns: 1.4fr repeat(4, 1fr);
  gap: 28px 24px;
}

.footer-brand-name {
  font-family: var(--serif);
  font-size: 17px;
  color: var(--ink);
  margin: 0 0 8px;
  font-weight: 700;
}

.footer-brand-desc {
  margin: 0;
  line-height: 1.7;
}

.footer-group-title {
  font-size: 15px;
  margin: 0 0 10px;
  color: var(--ink);
}

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

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

.footer-bottom {
  border-top: 1px solid var(--line);
  max-width: var(--container);
  margin: 0 auto;
  padding: 16px 24px 28px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-note,
.footer-copy {
  margin: 0;
}

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

.section {
  padding: 40px 0 8px;
  border-top: 1px solid var(--line);
  margin-top: 32px;
}

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

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

.section-lead {
  color: var(--ink-soft);
  margin: 0;
  max-width: 760px;
}

.section-text {
  color: var(--ink-soft);
  max-width: 820px;
}

.section-media {
  margin-top: 20px;
}

.section-media img,
.channel-figure img,
.media-figure img,
.guide-figure img,
.qa-figure img,
.hero-media img,
.special-figure img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: var(--radius);
  object-fit: cover;
  background: #e6ded2;
}

.section-media figcaption,
.channel-figure figcaption,
.media-figure figcaption,
.guide-figure figcaption,
.qa-figure figcaption,
.hero-caption,
.special-caption,
.figure-caption,
.qa-figure-caption {
  font-size: 14px;
  color: var(--ink-soft);
  margin-top: 8px;
}

.btn {
  display: inline-block;
  padding: 11px 20px;
  border-radius: var(--radius);
  font-size: 15px;
  border: 1px solid var(--accent);
  min-height: 44px;
  line-height: 20px;
}

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

.btn-primary:hover,
.btn-primary:focus-visible {
  background: var(--accent-deep);
  border-color: var(--accent-deep);
  color: #fff;
  text-decoration: none;
}

.btn-ghost {
  background: transparent;
  color: var(--accent-deep);
}

.btn-ghost:hover,
.btn-ghost:focus-visible {
  background: #f0e7da;
  text-decoration: none;
}

.data-table,
.fields-table,
.channel-table,
.criteria-table,
.obstacle-table {
  width: 100%;
  font-size: 15px;
  border: 1px solid var(--line);
  background: var(--card);
}

.data-table caption,
.fields-table caption,
.channel-table caption,
.criteria-table caption,
.obstacle-table caption,
.table-caption {
  caption-side: top;
  text-align: left;
  font-size: 14px;
  color: var(--ink-soft);
  padding: 0 0 8px;
}

.data-table th,
.data-table td,
.fields-table th,
.fields-table td,
.channel-table th,
.channel-table td,
.criteria-table th,
.criteria-table td,
.obstacle-table th,
.obstacle-table td {
  border-bottom: 1px solid var(--line);
  padding: 12px 14px;
  text-align: left;
  vertical-align: top;
}

.data-table thead th,
.fields-table thead th,
.channel-table thead th,
.criteria-table thead th,
.obstacle-table thead th {
  background: #f0e7da;
  font-family: var(--serif);
  font-size: 15px;
  color: var(--ink);
}

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

.step-list {
  counter-reset: none;
}

.step-item {
  display: flex;
  gap: 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.step-no,
.step-index {
  flex: 0 0 auto;
  width: 34px;
  height: 34px;
  border: 1px solid var(--accent);
  border-radius: 50%;
  color: var(--accent-deep);
  font-family: var(--serif);
  font-size: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.step-title,
.step-name {
  font-size: 18px;
  margin-bottom: 4px;
}

.step-text {
  margin: 0;
  color: var(--ink-soft);
}

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

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

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

.faq-list .faq-item {
  margin-bottom: 0;
}

.faq-question {
  cursor: pointer;
  padding: 14px 18px;
  font-family: var(--serif);
  font-size: 17px;
  color: var(--ink);
  list-style: none;
  position: relative;
  padding-right: 44px;
}

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

.faq-question::after {
  content: "+";
  position: absolute;
  right: 18px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--accent);
  font-size: 20px;
}

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

.faq-answer {
  padding: 0 18px 16px;
  color: var(--ink-soft);
}

.faq-answer p {
  margin: 0;
}

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

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

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

.page-header {
  padding-bottom: 20px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 8px;
}

.page-title {
  font-size: 32px;
  margin-bottom: 10px;
}

.page-description {
  color: var(--ink-soft);
  margin: 0;
  max-width: 820px;
}

/* ============ index ============ */

.hero-section {
  display: grid;
  grid-template-columns: minmax(0, 1.9fr) minmax(0, 1fr);
  gap: 32px;
  padding: 36px 0 8px;
}

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

.hero-kicker {
  font-size: 14px;
  color: var(--rational);
  text-transform: none;
  margin: 0 0 10px;
}

.hero-title {
  font-size: 34px;
  margin-bottom: 14px;
}

.hero-text {
  color: var(--ink-soft);
  max-width: 640px;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin: 20px 0 24px;
}

.hero-media img {
  aspect-ratio: 16 / 9;
}

.hero-side {
  display: grid;
  gap: 16px;
  align-content: start;
  min-width: 0;
}

.side-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 16px 18px;
}

.side-card-index {
  font-size: 13px;
  color: var(--rational);
  margin: 0 0 6px;
  font-family: var(--serif);
}

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

.side-card-text {
  margin: 0;
  color: var(--ink-soft);
  font-size: 15px;
}

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

.channel-row {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr) minmax(0, 1.4fr);
  gap: 16px;
  align-items: baseline;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.channel-no,
.channel-index {
  font-family: var(--serif);
  color: var(--accent);
  font-size: 15px;
}

.channel-name {
  font-size: 18px;
  margin: 0;
}

.channel-trend,
.channel-orientation {
  margin: 0;
  color: var(--ink-soft);
  font-size: 15px;
}

.channel-scope {
  margin: 0;
  color: var(--ink-soft);
  font-size: 15px;
}

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

.special-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  min-width: 0;
}

.special-card-no {
  font-family: var(--serif);
  color: var(--accent);
  font-size: 14px;
  margin: 0 0 8px;
}

.special-card-title {
  font-size: 19px;
  margin-bottom: 8px;
}

.special-card-scope,
.special-card-criteria {
  margin: 0 0 8px;
  color: var(--ink-soft);
  font-size: 15px;
}

.special-card-criteria {
  margin-bottom: 0;
}

.fields-summary .fields-table {
  display: table;
}

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

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

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

.log-item {
  display: grid;
  grid-template-columns: 140px minmax(0, 1fr);
  gap: 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.log-date {
  font-family: var(--serif);
  color: var(--accent);
  font-size: 15px;
}

.log-text {
  margin: 0;
  color: var(--ink-soft);
}

.faq-section .faq-list {
  margin-top: 4px;
}

/* ============ channel page ============ */

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

.channel-rows .channel-row {
  grid-template-columns: 56px minmax(0, 1fr);
  align-items: start;
}

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

.channel-rows .channel-name {
  font-size: 18px;
  margin: 0 0 4px;
}

.channel-rows .channel-orientation {
  margin: 0 0 4px;
}

.channel-rows .channel-scope {
  margin: 0;
}

.channel-compare .channel-table {
  margin-top: 4px;
}

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

.audience-column {
  border-left: 3px solid var(--rational);
  padding: 4px 0 4px 16px;
  min-width: 0;
}

.audience-name {
  font-size: 18px;
  margin-bottom: 6px;
}

.audience-text {
  margin: 0;
  color: var(--ink-soft);
}

.channel-entry .entry-back {
  margin-top: 18px;
}

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

/* ============ special page ============ */

.special-list-section .special-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 22px;
}

.special-list .special-card {
  padding: 0;
  overflow: hidden;
}

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

.special-figure figcaption {
  padding: 0 20px;
}

.special-list .special-name,
.special-list .special-scope,
.special-list .special-criteria {
  padding: 0 20px;
}

.special-list .special-name {
  font-size: 19px;
  margin: 12px 0 8px;
}

.special-scope,
.special-criteria {
  margin: 0 0 10px;
  color: var(--ink-soft);
  font-size: 15px;
}

.special-list .special-criteria {
  padding-bottom: 20px;
  margin-bottom: 0;
}

.scope-section .scope-list {
  display: grid;
  gap: 18px;
}

.scope-item {
  border-left: 3px solid var(--accent);
  padding-left: 16px;
}

.scope-heading {
  font-size: 18px;
  margin-bottom: 6px;
}

.scope-item p {
  margin: 0 0 8px;
  color: var(--ink-soft);
}

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

.criteria-section .criteria-table {
  margin-top: 4px;
}

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

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

.advice-heading {
  font-size: 18px;
  margin-bottom: 6px;
}

.advice-item p {
  margin: 0;
  color: var(--ink-soft);
}

/* ============ fields page ============ */

.media-figure img {
  aspect-ratio: 21 / 9;
}

.section-boundary-note .note-list {
  display: grid;
  gap: 18px;
}

.note-item {
  border-left: 3px solid var(--rational);
  padding-left: 16px;
}

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

.note-item p {
  margin: 0;
  color: var(--ink-soft);
}

.section-relation-note .relation-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
}

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

.relation-title {
  font-size: 18px;
  margin-bottom: 10px;
}

.relation-list li {
  padding: 8px 0;
  border-bottom: 1px solid var(--line);
  color: var(--ink-soft);
}

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

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

.related-item {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
  flex-wrap: wrap;
}

.related-desc {
  color: var(--ink-soft);
  font-size: 15px;
}

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

.guide-visual .guide-visual-body {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  gap: 24px;
  align-items: start;
}

.guide-figure img {
  aspect-ratio: 16 / 10;
}

.guide-visual-note {
  color: var(--ink-soft);
}

.guide-visual-note p:last-child {
  margin-bottom: 0;
}

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

.verify-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-top: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 18px;
  min-width: 0;
}

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

.verify-card p {
  margin: 0;
  color: var(--ink-soft);
}

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

.checklist-item {
  display: flex;
  gap: 14px;
  align-items: baseline;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.checklist-index {
  font-family: var(--serif);
  color: var(--accent);
  flex: 0 0 auto;
}

.checklist-item p {
  margin: 0;
  color: var(--ink-soft);
}

.checklist-more {
  margin-top: 18px;
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

/* ============ faq page ============ */

.qa-figure img {
  aspect-ratio: 21 / 9;
}

.qa-group {
  padding-top: 36px;
  margin-top: 28px;
  border-top: 1px solid var(--line);
}

.section-intro {
  color: var(--ink-soft);
  margin: 0 0 18px;
  max-width: 820px;
}

.adjustment-note {
  padding-top: 36px;
  margin-top: 28px;
  border-top: 1px solid var(--line);
}

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

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

.subsection-title {
  font-size: 18px;
  margin-bottom: 8px;
}

.feedback-column p {
  margin: 0 0 10px;
  color: var(--ink-soft);
}

.feedback-column p:last-child {
  margin-bottom: 0;
}

.feedback-links {
  margin-top: 18px;
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
}

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

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

.error-panel {
  max-width: 640px;
  margin: 0 auto;
  text-align: left;
}

.error-code {
  font-family: var(--serif);
  font-size: 56px;
  color: var(--accent);
  margin: 0 0 8px;
  line-height: 1;
}

.error-text {
  color: var(--ink-soft);
}

.error-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 20px;
  margin: 20px 0 24px;
}

.error-home-btn {
  display: inline-block;
  padding: 11px 22px;
  background: var(--accent);
  color: #fff;
  border-radius: var(--radius);
  min-height: 44px;
  line-height: 20px;
}

.error-home-btn:hover,
.error-home-btn:focus-visible {
  background: var(--accent-deep);
  color: #fff;
  text-decoration: none;
}

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

@media (max-width: 900px) {
  .footer-inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

  .special-cards,
  .audience-columns,
  .advice-list,
  .verify-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (max-width: 768px) {
  .header-inner {
    padding: 12px 16px;
    gap: 12px;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    flex: 0 0 100%;
    margin-left: 0;
    order: 3;
  }

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

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

  .nav-link {
    padding: 12px 4px;
    border-bottom: 1px solid var(--line);
    border-left: 2px solid transparent;
  }

  .nav-link:hover,
  .nav-link:focus-visible,
  .nav-link.is-current {
    border-bottom-color: var(--line);
    border-left-color: var(--accent);
  }

  .site-main {
    padding: 0 16px 44px;
  }

  .hero-title {
    font-size: 27px;
  }

  .page-title {
    font-size: 25px;
  }

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

  .special-cards,
  .audience-columns,
  .advice-list,
  .verify-grid,
  .relation-grid,
  .feedback-columns,
  .guide-visual-body,
  .special-list-section .special-list,
  .channel-audience .audience-columns,
  .advice-section .advice-list,
  .verify-note .verify-grid,
  .section-relation-note .relation-grid,
  .guide-visual .guide-visual-body {
    grid-template-columns: minmax(0, 1fr);
  }

  .channel-row {
    grid-template-columns: 40px minmax(0, 1fr);
    gap: 12px;
  }

  .channel-row .channel-scope {
    grid-column: 2;
  }

  .channel-rows .channel-row {
    grid-template-columns: 40px minmax(0, 1fr);
  }

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

  .data-table th,
  .data-table td,
  .fields-table th,
  .fields-table td,
  .channel-table th,
  .channel-table td,
  .criteria-table th,
  .criteria-table td,
  .obstacle-table th,
  .obstacle-table td {
    padding: 10px 10px;
    font-size: 14px;
  }
}

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

  .header-inner {
    padding: 10px 14px;
  }

  .brand {
    font-size: 17px;
  }

  .site-main {
    padding: 0 14px 40px;
  }

  .footer-inner {
    grid-template-columns: minmax(0, 1fr);
    padding: 28px 14px 20px;
    gap: 22px;
  }

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

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

  .page-title {
    font-size: 22px;
  }

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

  .btn {
    text-align: center;
  }

  .step-item {
    gap: 12px;
  }

  .special-card {
    padding: 16px;
  }

  .special-list .special-name,
  .special-list .special-scope,
  .special-list .special-criteria,
  .special-figure figcaption {
    padding-left: 16px;
    padding-right: 16px;
  }
}