:root {
  --ink: #0e1116;
  --ink-2: #141922;
  --paper: #e8e6e1;
  --paper-dim: #9aa3af;
  --accent: #3d5a99;
  --line: #2a3140;
  --line-strong: #3a4356;
  --mono: ui-monospace, "SFMono-Regular", "Menlo", "Consolas", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --wrap: 1080px;
  --gutter: 24px;
  --header-h: 66px;
}

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

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

body.site-body {
  margin: 0;
  background: var(--ink-2);
  color: var(--paper);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.75;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

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

a:hover {
  color: #fff;
}

h1, h2, h3 {
  margin: 0;
  font-weight: 800;
  line-height: 1.3;
  color: var(--paper);
}

p {
  margin: 0;
}

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

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

button {
  font-family: inherit;
  cursor: pointer;
}

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

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

.site-header {
  background: var(--ink);
  border-bottom: 2px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 40;
}

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

.brand {
  display: flex;
  align-items: baseline;
  gap: 10px;
  flex-shrink: 0;
}

.brand-mark {
  font-size: 19px;
  font-weight: 800;
  letter-spacing: 0.04em;
  color: var(--paper);
}

.brand-sub {
  font-size: 12px;
  color: var(--paper-dim);
  font-family: var(--mono);
  letter-spacing: 0.02em;
}

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

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

.nav-item {
  display: block;
}

.nav-link {
  display: block;
  padding: 8px 12px;
  font-size: 14px;
  color: var(--paper-dim);
  border-bottom: 2px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.nav-link:hover {
  color: var(--paper);
}

.nav-link.is-current {
  color: var(--paper);
  border-bottom-color: var(--accent);
}

.nav-toggle {
  display: none;
  margin-left: auto;
  width: 44px;
  height: 44px;
  padding: 0;
  background: transparent;
  border: 2px solid var(--line-strong);
  border-radius: 4px;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--paper);
}

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

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

.site-footer {
  background: var(--ink);
  border-top: 2px solid var(--line);
  margin-top: 56px;
}

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

.footer-brand-name {
  font-size: 16px;
  font-weight: 800;
  letter-spacing: 0.03em;
}

.footer-brand-desc {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--paper-dim);
  max-width: 260px;
}

.footer-col-title {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--paper);
  padding-bottom: 10px;
  border-bottom: 2px solid var(--line);
  margin-bottom: 12px;
}

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

.footer-list a {
  font-size: 13px;
  color: var(--paper-dim);
}

.footer-list a:hover {
  color: var(--paper);
}

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

.footer-copy {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 16px var(--gutter);
  font-size: 12px;
  color: var(--paper-dim);
  font-family: var(--mono);
}

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

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

.fact-bar-text {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 9px var(--gutter);
  font-size: 13px;
  color: var(--paper-dim);
}

.fact-bar-text a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.fact-bar-text a:hover {
  color: #6d87c4;
}

.section-title {
  font-size: 22px;
  font-weight: 800;
  letter-spacing: 0.01em;
}

.section-intro {
  margin-top: 10px;
  font-size: 14px;
  color: var(--paper-dim);
  max-width: 720px;
}

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

.section-intro a:hover {
  color: #6d87c4;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 20px 0 0;
  font-size: 13px;
  color: var(--paper-dim);
}

.breadcrumb a {
  color: var(--paper-dim);
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

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

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

.page-header {
  padding: 22px 0 26px;
  border-bottom: 2px solid var(--line);
  margin-bottom: 32px;
}

.page-title {
  font-size: 28px;
  font-weight: 800;
  letter-spacing: 0.01em;
}

.page-lead,
.page-description {
  margin-top: 12px;
  font-size: 14px;
  color: var(--paper-dim);
  max-width: 720px;
}

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

.page-facts {
  margin-top: 20px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 32px;
}

.fact-row {
  display: flex;
  gap: 10px;
  align-items: baseline;
  font-size: 13px;
}

.fact-label {
  color: var(--paper-dim);
  font-family: var(--mono);
}

.fact-value {
  color: var(--paper);
}

.page-meta {
  margin-top: 18px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 28px;
  font-size: 13px;
}

.page-meta dt {
  color: var(--paper-dim);
  font-family: var(--mono);
}

.page-meta dd {
  color: var(--paper);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 22px;
  font-size: 14px;
  font-weight: 700;
  border: 2px solid var(--line-strong);
  border-radius: 4px;
  transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

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

.btn-primary:hover {
  background: #4d6cae;
  border-color: #4d6cae;
  color: #fff;
}

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

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

.section-media {
  margin-top: 24px;
  border: 2px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
  background: var(--ink);
}

.section-media img {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.media-caption {
  padding: 10px 14px;
  font-size: 12px;
  color: var(--paper-dim);
  border-top: 1px solid var(--line);
  font-family: var(--mono);
}

.related-bar {
  margin-top: 40px;
  padding-top: 24px;
  border-top: 2px solid var(--line);
}

.related-title {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--paper-dim);
  margin-bottom: 14px;
}

.related-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.related-list li {
  display: block;
}

.related-item a,
.section-related .related-item a {
  display: inline-block;
  padding: 9px 16px;
  font-size: 13px;
  border: 2px solid var(--line-strong);
  border-radius: 4px;
  color: var(--paper);
  transition: border-color 0.15s ease, color 0.15s ease;
}

.related-item a:hover {
  border-color: var(--accent);
  color: #fff;
}

/* ============ pages: index ============ */

.hero-section {
  padding: 48px 0 40px;
  border-bottom: 2px solid var(--line);
}

.hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 44px;
  align-items: center;
}

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

.hero-eyebrow {
  font-size: 12px;
  font-family: var(--mono);
  letter-spacing: 0.12em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 14px;
}

.hero-title {
  font-size: 32px;
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: 0.01em;
}

.hero-lead {
  margin-top: 16px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--paper-dim);
  max-width: 34em;
}

.hero-actions {
  margin-top: 26px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.hero-media {
  border: 2px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
  background: var(--ink);
}

.hero-media img {
  width: 100%;
  height: auto;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.hero-caption {
  padding: 10px 14px;
  font-size: 12px;
  color: var(--paper-dim);
  border-top: 1px solid var(--line);
  font-family: var(--mono);
}

.log-section,
.channel-overview,
.collection-entry,
.order-section,
.boundary-summary,
.site-index {
  padding: 40px 0;
  border-bottom: 2px solid var(--line);
}

.log-list {
  margin-top: 22px;
  border: 2px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
}

.log-item {
  display: grid;
  grid-template-columns: 110px minmax(0, 1fr) 200px;
  gap: 16px;
  padding: 12px 16px;
  font-size: 13px;
  border-bottom: 1px solid var(--line);
  align-items: baseline;
}

.log-item:last-child {
  border-bottom: 0;
}

.log-stage {
  font-family: var(--mono);
  color: var(--accent);
  letter-spacing: 0.04em;
}

.log-action {
  color: var(--paper);
}

.log-field {
  color: var(--paper-dim);
  font-family: var(--mono);
  text-align: right;
}

.channel-rows {
  margin-top: 22px;
  border-top: 2px solid var(--line);
}

.channel-row {
  display: grid;
  grid-template-columns: 64px 180px minmax(0, 1fr) 200px;
  gap: 16px;
  padding: 16px;
  border-bottom: 1px solid var(--line);
  border-left: 2px solid transparent;
  border-right: 2px solid transparent;
  align-items: baseline;
  transition: border-color 0.15s ease, background-color 0.15s ease;
}

.channel-row:hover {
  border-left-color: var(--accent);
  border-right-color: var(--accent);
  background: rgba(61, 90, 153, 0.08);
}

.channel-code {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--accent);
  letter-spacing: 0.04em;
}

.channel-name {
  font-size: 17px;
  font-weight: 700;
  color: var(--paper);
}

.channel-scope {
  font-size: 14px;
  color: var(--paper-dim);
}

.channel-scene {
  font-size: 13px;
  color: var(--paper-dim);
  font-family: var(--mono);
}

.collection-grid {
  margin-top: 22px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.collection-card {
  border: 2px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
  background: var(--ink);
  padding: 0 0 18px;
  transition: border-color 0.15s ease;
}

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

.collection-media {
  border-bottom: 1px solid var(--line);
}

.collection-media img {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.collection-name {
  padding: 16px 18px 0;
  font-size: 17px;
  font-weight: 700;
}

.collection-count {
  padding: 6px 18px 0;
  font-size: 12px;
  font-family: var(--mono);
  color: var(--accent);
  letter-spacing: 0.04em;
}

.collection-desc {
  padding: 10px 18px 0;
  font-size: 14px;
  color: var(--paper-dim);
}

.order-steps {
  margin-top: 22px;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.order-step {
  border: 2px solid var(--line);
  border-radius: 6px;
  padding: 18px 16px 20px;
  display: flex;
  flex-direction: column;
}

.step-num {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--accent);
  letter-spacing: 0.08em;
  margin-bottom: 10px;
}

.order-step .step-name {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 10px;
}

.order-step .step-action {
  font-size: 14px;
  color: var(--paper-dim);
  flex: 1 0 auto;
}

.order-step .step-check {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  color: var(--paper-dim);
  font-family: var(--mono);
}

.boundary-columns {
  margin-top: 22px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
}

.boundary-col {
  border: 2px solid var(--line);
  border-radius: 6px;
  padding: 20px;
}

.boundary-col-title {
  font-size: 16px;
  font-weight: 700;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 14px;
}

.boundary-item {
  display: flex;
  gap: 12px;
  padding: 8px 0;
  font-size: 14px;
  color: var(--paper-dim);
  align-items: baseline;
}

.boundary-key {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--accent);
  flex-shrink: 0;
}

.index-grid {
  margin-top: 22px;
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 14px;
}

.index-cell {
  border: 2px solid var(--line);
  border-radius: 6px;
  padding: 16px 14px;
  transition: border-color 0.15s ease;
}

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

.index-link {
  display: block;
  font-size: 15px;
  font-weight: 700;
  color: var(--paper);
}

.index-desc {
  margin-top: 8px;
  font-size: 12px;
  color: var(--paper-dim);
  line-height: 1.6;
}

/* ============ pages: inner ============ */

.page-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 40px;
  align-items: start;
}

.page-main,
.layout-main,
.content-main {
  min-width: 0;
}

.content-aside,
.page-aside,
.layout-aside {
  min-width: 0;
  position: sticky;
  top: calc(var(--header-h) + 20px);
}

.aside-block {
  border: 2px solid var(--line);
  border-radius: 6px;
  padding: 18px;
  margin-bottom: 20px;
  background: var(--ink);
}

.aside-title {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--paper);
  padding-bottom: 10px;
  border-bottom: 2px solid var(--line);
  margin-bottom: 12px;
}

.aside-sub {
  font-size: 13px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 8px;
}

.aside-group {
  margin-bottom: 14px;
}

.aside-group:last-child {
  margin-bottom: 0;
}

.aside-list li,
.aside-link-list li,
.aside-links li {
  margin-bottom: 8px;
}

.aside-list li {
  font-size: 13px;
  color: var(--paper-dim);
}

.aside-link-list a,
.aside-links a {
  display: block;
  padding: 8px 0;
  font-size: 13px;
  color: var(--paper-dim);
  border-bottom: 1px solid var(--line);
  transition: color 0.15s ease;
}

.aside-link-list li:last-child a,
.aside-links li:last-child a {
  border-bottom: 0;
}

.aside-link-list a:hover,
.aside-links a:hover {
  color: var(--paper);
}

.aside-note,
.aside-text {
  margin-top: 12px;
  font-size: 12px;
  color: var(--paper-dim);
  line-height: 1.65;
}

.field-list .field-row {
  display: flex;
  gap: 10px;
  padding: 8px 0;
  border-bottom: 1px solid var(--line);
  font-size: 13px;
  align-items: baseline;
}

.field-list .field-row:last-child {
  border-bottom: 0;
}

.field-name {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--accent);
  flex-shrink: 0;
  min-width: 68px;
}

.field-def {
  color: var(--paper-dim);
}

.section {
  padding: 0 0 32px;
  margin-bottom: 32px;
  border-bottom: 2px solid var(--line);
}

.section:last-of-type {
  border-bottom: 0;
  margin-bottom: 0;
}

.section-footnote {
  margin-top: 18px;
  font-size: 13px;
  color: var(--paper-dim);
}

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

.section-footnote a:hover {
  color: #6d87c4;
}

/* channels */

.channel-list {
  margin-top: 22px;
  border-top: 2px solid var(--line);
}

.channel-list .channel-row {
  grid-template-columns: 64px 180px minmax(0, 1fr);
  grid-template-areas:
    "code name scope"
    "code scene scene";
  row-gap: 6px;
}

.channel-list .channel-code {
  grid-area: code;
}

.channel-list .channel-name {
  grid-area: name;
}

.channel-list .channel-scope {
  grid-area: scope;
}

.channel-list .channel-scene {
  grid-area: scene;
}

.division-list {
  margin-top: 20px;
}

.division-item {
  border-left: 2px solid var(--line);
  padding: 4px 0 4px 18px;
  margin-bottom: 18px;
}

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

.division-name {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 6px;
}

.division-text {
  font-size: 14px;
  color: var(--paper-dim);
}

.relation-columns {
  margin-top: 20px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.relation-col {
  border: 2px solid var(--line);
  border-radius: 6px;
  padding: 18px;
}

.relation-col-title {
  font-size: 15px;
  font-weight: 700;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 12px;
}

.relation-points li {
  position: relative;
  padding-left: 16px;
  margin-bottom: 8px;
  font-size: 14px;
  color: var(--paper-dim);
}

.relation-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 2px;
  background: var(--accent);
}

/* collections */

.collection-item {
  border: 2px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
  background: var(--ink);
  transition: border-color 0.15s ease;
}

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

.collection-body {
  padding: 16px 18px 18px;
}

.collection-item .collection-name {
  padding: 0;
  font-size: 17px;
  font-weight: 700;
}

.collection-item .collection-count {
  padding: 6px 0 0;
}

.collection-item .collection-desc {
  padding: 10px 0 0;
}

.logic-list {
  margin-top: 20px;
  counter-reset: logic;
}

.logic-item {
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.logic-item:last-child {
  border-bottom: 0;
}

.logic-name {
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 6px;
}

.logic-text {
  font-size: 14px;
  color: var(--paper-dim);
}

.mapping-grid {
  margin-top: 20px;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.mapping-col {
  border: 2px solid var(--line);
  border-radius: 6px;
  padding: 18px;
}

.mapping-head {
  font-size: 15px;
  font-weight: 700;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 12px;
}

.mapping-list li {
  padding: 6px 0;
  font-size: 14px;
  color: var(--paper-dim);
  font-family: var(--mono);
}

.mapping-note {
  margin-top: 16px;
  font-size: 13px;
  color: var(--paper-dim);
}

.mapping-note a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* guide */

.page-header-text {
  min-width: 0;
}

.page-header-meta {
  margin-top: 20px;
  border: 2px solid var(--line);
  border-radius: 6px;
  padding: 16px 18px;
  background: var(--ink);
}

.meta-list {
  display: grid;
  gap: 8px;
}

.page-header-meta .meta-list {
  grid-template-columns: auto 1fr;
  column-gap: 16px;
}

.page-header-meta .meta-list dt {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--paper-dim);
}

.page-header-meta .meta-list dd {
  font-size: 13px;
  color: var(--paper);
}

.content-section {
  padding: 0 0 32px;
  margin-bottom: 32px;
  border-bottom: 2px solid var(--line);
  scroll-margin-top: calc(var(--header-h) + 20px);
}

.content-section:last-of-type {
  border-bottom: 0;
  margin-bottom: 0;
}

.step-list {
  margin-top: 22px;
}

.step-item {
  border: 2px solid var(--line);
  border-radius: 6px;
  padding: 18px 20px;
  margin-bottom: 14px;
}

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

.step-index {
  display: inline-block;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: 8px;
}

.step-item .step-name {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 8px;
}

.step-item .step-action {
  font-size: 14px;
  color: var(--paper-dim);
}

.step-result,
.step-pre {
  margin-top: 10px;
  font-size: 13px;
  color: var(--paper-dim);
  padding-left: 14px;
  border-left: 2px solid var(--line);
}

.field-read-list {
  margin-top: 20px;
}

.field-read-item {
  display: grid;
  grid-template-columns: 120px minmax(0, 1fr);
  gap: 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  align-items: baseline;
}

.field-read-item:last-child {
  border-bottom: 0;
}

.field-read-name {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--accent);
}

.field-read-tip {
  font-size: 14px;
  color: var(--paper-dim);
}

.faq-list {
  margin-top: 20px;
}

.faq-item {
  border: 2px solid var(--line);
  border-radius: 6px;
  margin-bottom: 10px;
  background: var(--ink);
}

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

.faq-question {
  padding: 14px 18px;
  font-size: 15px;
  font-weight: 700;
  color: var(--paper);
  cursor: pointer;
  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%);
  font-family: var(--mono);
  font-size: 18px;
  color: var(--accent);
}

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

.faq-answer {
  padding: 0 18px 16px;
  font-size: 14px;
  color: var(--paper-dim);
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

/* boundary */

.layout-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 40px;
  align-items: start;
}

.section-fields,
.section-boundary,
.section-log {
  scroll-margin-top: calc(var(--header-h) + 20px);
}

.field-table {
  margin-top: 20px;
  border-top: 2px solid var(--line);
}

.field-row {
  display: grid;
  grid-template-columns: 140px minmax(0, 1fr);
  gap: 18px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  align-items: baseline;
}

.field-table .field-name {
  font-size: 13px;
}

.boundary-list {
  margin-top: 20px;
}

.boundary-item {
  border-left: 2px solid var(--line);
  padding: 4px 0 4px 18px;
  margin-bottom: 16px;
}

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

.boundary-item.is-in {
  border-left-color: var(--accent);
}

.boundary-item.is-out {
  border-left-color: var(--line-strong);
}

.boundary-title {
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 6px;
}

.boundary-text {
  font-size: 14px;
  color: var(--paper-dim);
}

.section-log {
  padding-top: 32px;
  border-top: 2px solid var(--line);
}

.log-group {
  margin-top: 20px;
  border: 2px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
}

.log-stage {
  font-size: 14px;
  font-weight: 700;
  padding: 12px 16px;
  background: var(--ink);
  border-bottom: 1px solid var(--line);
  color: var(--paper);
}

.log-group .log-list .log-item {
  grid-template-columns: minmax(0, 1fr) 200px;
}

.log-group .log-action {
  font-size: 14px;
}

.section-related {
  margin-top: 40px;
  padding-top: 28px;
  border-top: 2px solid var(--line);
}

.section-related .related-list {
  margin-top: 16px;
}

/* 404 */

.error-main {
  padding-top: 60px;
  padding-bottom: 60px;
}

.error-block {
  border: 2px solid var(--line);
  border-radius: 6px;
  padding: 40px 32px;
  background: var(--ink);
}

.error-code {
  font-family: var(--mono);
  font-size: 14px;
  letter-spacing: 0.16em;
  color: var(--accent);
  margin-bottom: 14px;
}

.error-title {
  font-size: 28px;
  font-weight: 800;
}

.error-desc {
  margin-top: 14px;
  font-size: 14px;
  color: var(--paper-dim);
  max-width: 560px;
}

.error-home-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  margin-top: 24px;
  padding: 0 22px;
  font-size: 14px;
  font-weight: 700;
  border: 2px solid var(--accent);
  border-radius: 4px;
  color: #fff;
  background: var(--accent);
}

.error-home-link:hover {
  background: #4d6cae;
  border-color: #4d6cae;
  color: #fff;
}

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

.error-paths-title {
  font-size: 18px;
  font-weight: 800;
}

.error-path-list {
  margin-top: 18px;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.error-path-item a {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: 10px 16px;
  font-size: 14px;
  border: 2px solid var(--line-strong);
  border-radius: 4px;
  color: var(--paper);
  transition: border-color 0.15s ease;
}

.error-path-item a:hover {
  border-color: var(--accent);
  color: #fff;
}

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

@media (max-width: 960px) {
  :root {
    --gutter: 20px;
  }

  .header-inner {
    gap: 16px;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    background: var(--ink);
    border-bottom: 2px solid var(--line);
    padding: 0 var(--gutter);
  }

  .nav-list {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 0;
  }

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

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

  .nav-item:last-child {
    border-bottom: 0;
  }

  .nav-link {
    display: flex;
    align-items: center;
    min-height: 44px;
    padding: 0 4px;
    border-bottom: 0;
    border-left: 2px solid transparent;
    padding-left: 12px;
  }

  .nav-link.is-current {
    border-bottom-color: transparent;
    border-left-color: var(--accent);
    color: var(--paper);
  }

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

  .hero-title {
    font-size: 28px;
  }

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

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

  .content-aside,
  .page-aside,
  .layout-aside {
    position: static;
  }

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

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

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

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

@media (max-width: 640px) {
  body.site-body {
    font-size: 14px;
  }

  .brand-sub {
    display: none;
  }

  .hero-section {
    padding: 32px 0 28px;
  }

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

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

  .section-title {
    font-size: 19px;
  }

  .log-section,
  .channel-overview,
  .collection-entry,
  .order-section,
  .boundary-summary,
  .site-index {
    padding: 28px 0;
  }

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

  .log-field {
    text-align: left;
  }

  .channel-row,
  .channel-list .channel-row {
    grid-template-columns: 56px minmax(0, 1fr);
    grid-template-areas:
      "code name"
      "scope scope"
      "scene scene";
    gap: 6px 12px;
    padding: 14px 12px;
  }

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

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

  .boundary-columns {
    grid-template-columns: minmax(0, 1fr);
    gap: 16px;
  }

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

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

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

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

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

  .footer-brand-desc {
    max-width: none;
  }
}