.page-about {
  --about-panel: rgba(18, 49, 42, 0.5);
  --about-line-soft: rgba(29, 74, 62, 0.75);
  display: block;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumbs {
  padding-top: 22px;
  font-family: var(--font-mono);
  font-size: 12px;
}

/* ---------- 首屏：上重下轻的错位标题区 ---------- */
.page-about .about-hero {
  padding-top: 18px;
  padding-bottom: 24px;
}

.page-about .about-hero__top {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  align-items: end;
}

.page-about .about-hero__media {
  margin: 0;
  position: relative;
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 1px solid var(--line);
  clip-path: polygon(0 5%, 100% 0, 100% 90%, 0 100%);
}

.page-about .about-hero__media figcaption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--faint);
}

.page-about .about-hero__note {
  margin: 0;
  font-family: var(--font-head);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.22em;
  color: var(--faint);
  border-top: 1px solid var(--line);
  padding-top: 10px;
}

.page-about .about-hero__lead {
  margin-top: 30px;
  max-width: 100%;
}

.page-about .about-hero__lead h1 {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(34px, 8.4vw, 76px);
  line-height: 1.02;
  letter-spacing: -0.01em;
  margin: 0.18em 0 0.34em;
  color: var(--text);
}

.page-about .about-hero__dek {
  margin: 0;
  max-width: 60ch;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.75;
}

@media (min-width: 860px) {
  .page-about .about-hero__top {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 0.4fr);
    gap: 32px;
  }

  .page-about .about-hero__note {
    writing-mode: vertical-rl;
    justify-self: end;
    align-self: stretch;
    border-top: 0;
    border-right: 1px solid var(--line);
    padding: 0 10px 0 0;
  }

  .page-about .about-hero__lead {
    max-width: 76%;
  }
}

/* ---------- 主体分栏：内容 + 章节索引 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 36px;
  padding-top: 34px;
  padding-bottom: 48px;
}

.page-about .about-main {
  min-width: 0;
}

.page-about .chapter-index {
  order: -1;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 6px;
  -webkit-overflow-scrolling: touch;
}

.page-about .chapter-index__link {
  flex: none;
  white-space: nowrap;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  padding: 6px 10px;
  border: 1px solid var(--line);
  color: var(--muted);
  text-decoration: none;
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .chapter-index__link:hover {
  color: var(--gold-soft);
  border-color: var(--gold);
}

.page-about .chapter-index__link[aria-current="true"] {
  color: var(--gold);
  border-color: var(--gold);
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: minmax(0, 1fr) 196px;
    gap: 56px;
    padding-top: 46px;
    padding-bottom: 72px;
  }

  .page-about .chapter-index {
    order: 0;
    flex-direction: column;
    gap: 0;
    overflow: visible;
    position: sticky;
    top: 96px;
    padding-bottom: 0;
  }

  .page-about .chapter-index__link {
    white-space: normal;
    border: 0;
    border-left: 1px solid var(--line);
    padding: 9px 0 9px 12px;
    font-size: 12.5px;
  }

  .page-about .chapter-index__link[aria-current="true"] {
    border-left-color: var(--gold);
  }
}

/* ---------- 章节骨架 ---------- */
.page-about .about-section {
  padding: 38px 0;
  border-top: 1px solid var(--line);
}

.page-about .about-section:first-child {
  border-top: 0;
  padding-top: 8px;
}

.page-about .about-section h2 {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(24px, 4.6vw, 36px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin: 10px 0 14px;
  max-width: 22ch;
}

.page-about .about-lead {
  margin: 0 0 6px;
  max-width: 64ch;
  color: var(--muted);
  font-size: 15.5px;
  line-height: 1.75;
}

.page-about .about-hint {
  margin: 22px 0 0;
  padding-left: 12px;
  border-left: 2px solid var(--cyan);
  color: var(--muted);
  font-size: 14px;
  line-height: 1.7;
  max-width: 60ch;
}

/* ---------- 信息组织三栏 ---------- */
.page-about .org-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  margin-top: 26px;
  border-top: 1px solid var(--line);
}

.page-about .org-item {
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .org-item__no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.1em;
  color: var(--gold);
}

.page-about .org-item__title {
  font-family: var(--font-head);
  font-size: 19px;
  margin: 8px 0 10px;
  color: var(--text);
}

.page-about .org-item p:last-child {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.75;
}

@media (min-width: 760px) {
  .page-about .org-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    column-gap: 28px;
  }

  .page-about .org-item {
    border-bottom: 0;
    padding-bottom: 4px;
  }
}

/* ---------- 三条准则：窄栏 + 右侧纵向注释 ---------- */
.page-about .section-side {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
  margin-top: 8px;
}

.page-about .section-side__main {
  min-width: 0;
}

.page-about .section-side__note {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--faint);
  border-top: 1px solid var(--line);
  padding-top: 10px;
}

@media (min-width: 1024px) {
  .page-about .section-side {
    grid-template-columns: minmax(0, 1fr) 60px;
    gap: 34px;
  }

  .page-about .section-side__note {
    writing-mode: vertical-rl;
    justify-self: end;
    border-top: 0;
    border-right: 1px solid var(--line);
    padding: 0 10px 0 0;
  }
}

.page-about .rules-index {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 4px 0 6px;
}

.page-about .rules-index a {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--cyan);
  text-decoration: none;
  border: 1px solid var(--line);
  padding: 6px 10px;
  transition: color 160ms var(--ease), border-color 160ms var(--ease);
}

.page-about .rules-index a:hover {
  color: var(--gold-soft);
  border-color: var(--gold);
}

.page-about .rule-item {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  gap: 14px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
  scroll-margin-top: 110px;
}

.page-about .rule-item:last-child {
  border-bottom: 0;
}

.page-about .rule-item__num {
  margin: 0;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 22px;
  line-height: 1;
  color: var(--gold);
  letter-spacing: -0.02em;
}

.page-about .rule-item__body {
  min-width: 0;
}

.page-about .rule-item__body h3 {
  font-family: var(--font-head);
  font-size: 19px;
  margin: 0 0 8px;
  color: var(--text);
}

.page-about .rule-item__body p {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.75;
}

.page-about .rule-item__body .rule-item__do {
  margin: 0;
  color: var(--text);
  font-size: 14px;
  border-left: 2px solid var(--gold);
  padding-left: 10px;
}

@media (min-width: 760px) {
  .page-about .rule-item {
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 24px;
  }

  .page-about .rule-item__num {
    font-size: 42px;
  }
}

/* ---------- 版本时间线 ---------- */
.page-about .timeline-figure {
  margin: 24px 0 30px;
}

.page-about .timeline-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 8 / 3;
  object-fit: cover;
  border: 1px solid var(--line);
  background: var(--ink-800);
}

.page-about .timeline-figure figcaption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--faint);
}

.page-about .timeline {
  position: relative;
  padding-left: 0;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  bottom: 18px;
  width: 1px;
  background: linear-gradient(180deg, var(--line) 0%, var(--line) 72%, rgba(29, 74, 62, 0) 100%);
}

.page-about .tl-node {
  position: relative;
  padding-left: 26px;
  padding-bottom: 20px;
}

.page-about .tl-node:last-child {
  padding-bottom: 0;
}

.page-about .tl-node::before {
  content: "";
  position: absolute;
  left: 1px;
  top: 16px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 1px solid var(--gold);
}

.page-about .tl-node:hover::before {
  box-shadow: 0 0 12px rgba(242, 193, 78, 0.25);
}

.page-about .tl-fold {
  background: var(--ink-800);
  border: 1px solid var(--line);
  transition: border-color 160ms var(--ease);
}

.page-about .tl-fold[open],
.page-about .tl-fold:hover {
  border-color: var(--gold);
}

.page-about .tl-fold > summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  padding: 14px 16px;
}

.page-about .tl-fold > summary::-webkit-details-marker {
  display: none;
}

.page-about .tl-fold > summary::after {
  content: "＋";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--faint);
}

.page-about .tl-fold[open] > summary::after {
  content: "－";
  color: var(--gold);
}

.page-about .tl-fold__ver {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.05em;
  color: var(--gold);
}

.page-about .tl-fold__title {
  font-family: var(--font-head);
  font-size: 17px;
  color: var(--text);
}

.page-about .tl-fold .fold__body {
  padding: 0 16px 16px;
  color: var(--muted);
  font-size: 14.5px;
  line-height: 1.75;
}

.page-about .tl-fold .fold__body ul {
  margin: 0;
  padding-left: 18px;
}

.page-about .tl-fold .fold__body li + li {
  margin-top: 6px;
}

@media (min-width: 1024px) {
  .page-about .tl-node {
    max-width: 74%;
  }

  .page-about .tl-node:nth-child(even) {
    margin-left: 44px;
  }

  .page-about .tl-node:nth-child(even)::before {
    left: -43px;
  }
}

/* ---------- 三审校验 ---------- */
.page-about .grid--7-5 {
  margin-top: 8px;
}

.page-about .review-steps {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  min-width: 0;
}

.page-about .review-step {
  display: grid;
  grid-template-columns: 38px minmax(0, 1fr);
  gap: 14px;
  padding: 18px 0;
  border-top: 1px solid var(--line);
}

.page-about .review-step:first-child {
  border-top: 0;
}

.page-about .review-step__no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  color: var(--gold);
  letter-spacing: 0.06em;
}

.page-about .review-step h3 {
  font-family: var(--font-head);
  font-size: 18px;
  margin: 0 0 6px;
  color: var(--text);
}

.page-about .review-step p {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.75;
}

.page-about .review-aside {
  margin-top: 26px;
  min-width: 0;
}

.page-about .review-media {
  margin: 0;
}

.page-about .review-media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 1px solid var(--line);
  background: var(--ink-700);
}

.page-about .review-media figcaption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--faint);
}

.page-about .review-aside__note {
  margin: 16px 0 0;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
  line-height: 1.7;
}

@media (min-width: 1000px) {
  .page-about .review-aside {
    margin-top: 18px;
  }
}

/* ---------- 误解澄清 ---------- */
.page-about .clarify-list {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
}

.page-about .clarify-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  padding: 20px 0;
  border-top: 1px solid var(--line);
}

.page-about .clarify-item__q {
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-family: var(--font-head);
  font-size: 17px;
  color: var(--text);
}

.page-about .clarify-item__q::before {
  content: "误解";
  flex: none;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--amber);
  border: 1px solid rgba(255, 138, 61, 0.45);
  padding: 2px 6px;
}

.page-about .clarify-item__a {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.75;
}

@media (min-width: 760px) {
  .page-about .clarify-item {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    gap: 30px;
    align-items: start;
  }
}

/* ---------- 继续查阅 ---------- */
.page-about .more-links {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
}

.page-about .more-links li {
  border-top: 1px solid var(--line);
}

.page-about .more-links li:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .more-links a {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 0;
  color: var(--text);
  font-size: 16px;
  text-decoration: none;
  transition: color 160ms var(--ease);
}

.page-about .more-links a::after {
  content: "→";
  margin-left: auto;
  font-family: var(--font-mono);
  color: var(--cyan);
}

.page-about .more-links a:hover {
  color: var(--gold);
}

.page-about .more-links a:hover::after {
  color: var(--gold);
}

@media (prefers-reduced-motion: reduce) {
  .page-about .chapter-index__link,
  .page-about .rules-index a,
  .page-about .tl-fold,
  .page-about .more-links a {
    transition: none;
  }
}