.page-about {
  --about-rule-soft: rgba(36, 46, 99, 0.55);
  --about-cyan-soft: rgba(44, 242, 224, 0.38);
  padding-bottom: 48px;
}

/* ============ 面包屑与首屏 ============ */
.page-about .breadcrumb {
  padding: 26px 0 0;
  font-size: 13px;
}

.page-about .about-head {
  padding: 30px 0 0;
}

.page-about .about-head__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
  padding-bottom: 40px;
  border-bottom: 1px solid var(--line);
}

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

.page-about .about-head h1 {
  margin: 10px 0 18px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 5.4vw, 54px);
  line-height: 1.14;
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-about .about-head__lead {
  margin: 0;
  max-width: 58ch;
  font-size: 16px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .facts-label {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--orange);
}

.page-about .facts-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .facts-list li {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 14px;
  padding: 11px 0;
  border-bottom: 1px solid var(--line-soft);
  font-size: 14px;
}

.page-about .facts-k {
  color: var(--muted);
}

.page-about .facts-v {
  color: var(--white);
  font-weight: 700;
}

@media (min-width: 901px) {
  .page-about .about-head__inner {
    grid-template-columns: minmax(0, 1.6fr) minmax(280px, 0.5fr);
    gap: 56px;
    align-items: start;
  }
}

/* ============ 章节通用 ============ */
.page-about .about-sec {
  padding: 56px 0 0;
}

.page-about .about-sec .section-head {
  margin-bottom: 28px;
}

.page-about .about-sec p a,
.page-about .records__note a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--about-cyan-soft);
}

.page-about .about-sec p a:hover,
.page-about .records__note a:hover {
  border-bottom-color: var(--cyan);
}

/* ============ 版本示意图 ============ */
.page-about .ver-figure {
  margin: 0 0 40px;
  border: 1px solid var(--line);
}

.page-about .ver-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.85);
}

.page-about .ver-figure__cap {
  display: block;
  padding: 9px 14px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  color: var(--muted);
}

/* ============ 时间线 ============ */
.page-about .tl-wrap {
  display: grid;
  grid-template-columns: 1fr;
  gap: 34px;
}

.page-about .tl {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.page-about .tl::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 6px;
  bottom: 12px;
  width: 1px;
  background: var(--line);
}

.page-about .tl__node {
  position: relative;
  padding: 0 0 42px 42px;
}

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

.page-about .tl__node::before {
  content: "";
  position: absolute;
  left: 0;
  top: 1px;
  width: 19px;
  height: 19px;
  box-sizing: border-box;
  border: 1px solid var(--line);
  background: var(--ink);
  z-index: 1;
}

.page-about .tl__node::after {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  width: 5px;
  height: 5px;
  background: var(--muted);
  z-index: 2;
  transition: background 0.35s ease;
}

.page-about .tl__node[data-reveal="in"]::after {
  background: var(--cyan);
}

.page-about .tl__node--current::before {
  border-color: var(--cyan);
}

.page-about .tl__node--current::after {
  background: var(--cyan);
}

.page-about .tl__ver {
  margin: 0 0 6px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--cyan);
}

.page-about .tl__name {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 19px;
  line-height: 1.42;
  color: var(--white);
}

.page-about .tl__text {
  margin: 0;
  max-width: 66ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

/* 版本索引 */
.page-about .tl-index {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 16px 16px 10px;
}

.page-about .tl-index__label {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--orange);
}

.page-about .tl-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .tl-index__list li + li {
  border-top: 1px solid var(--line-soft);
}

.page-about .tl-index__list a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 10px 4px 10px 8px;
  border-left: 2px solid transparent;
  color: var(--white);
  text-decoration: none;
  font-size: 13px;
  line-height: 1.5;
  transition: border-color 0.15s ease, color 0.15s ease;
}

.page-about .tl-index__list a:hover,
.page-about .tl-index__list a:focus-visible {
  border-left-color: var(--cyan);
  color: var(--cyan);
}

.page-about .tl-index__list .mono {
  flex: 0 0 46px;
  color: var(--muted);
}

.page-about .tl-index__list a:hover .mono {
  color: var(--cyan);
}

@media (min-width: 901px) {
  .page-about .tl-wrap {
    grid-template-columns: minmax(0, 1fr) 240px;
    gap: 52px;
    align-items: start;
  }

  .page-about .tl-index {
    position: sticky;
    top: 28px;
  }
}

/* ============ 四个小组 ============ */
.page-about .about-teams {
  row-gap: 36px;
}

.page-about .teams {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .teams__item {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 20px 0 22px 14px;
  border-bottom: 1px solid var(--line);
}

.page-about .teams__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--cyan);
  transform: scaleY(0);
  transform-origin: top center;
  transition: transform 0.2s ease;
}

.page-about .teams__item:hover::before,
.page-about .teams__item:focus-within::before {
  transform: scaleY(1);
}

.page-about .teams__no {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--orange);
}

.page-about .teams__name {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 17px;
  line-height: 1.5;
  color: var(--white);
}

.page-about .teams__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .teams-figure {
  margin: 0;
}

@media (min-width: 721px) {
  .page-about .teams__item {
    grid-template-columns: 46px 176px minmax(0, 1fr);
    gap: 0 20px;
    align-items: baseline;
    padding: 20px 0 22px 18px;
  }
}

@media (min-width: 901px) {
  .page-about .teams-figure {
    position: sticky;
    top: 28px;
  }
}

/* ============ 口径机制 ============ */
.page-about .protocol {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  border-top: 1px solid var(--line);
}

.page-about .protocol__item {
  padding: 22px 0 24px;
  border-bottom: 1px solid var(--line);
}

.page-about .protocol__no {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--orange);
}

.page-about .protocol__name {
  margin: 0 0 10px;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 17px;
  line-height: 1.55;
  color: var(--white);
}

.page-about .protocol__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .protocol__foot {
  margin: 22px 0 0;
  max-width: 78ch;
  font-size: 14px;
  line-height: 1.85;
  color: var(--muted);
}

@media (min-width: 861px) {
  .page-about .protocol {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .protocol__item {
    padding: 24px 24px 26px;
  }

  .page-about .protocol__item + .protocol__item {
    border-left: 1px solid var(--line);
  }
}

/* ============ 时效边界 ============ */
.page-about .boundary {
  border: 1px solid var(--line);
  border-left: 3px solid var(--orange);
  background: var(--panel);
  padding: 26px 22px 24px;
}

.page-about .boundary__label {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--orange);
}

.page-about .boundary .section-title {
  margin: 0 0 16px;
  padding-bottom: 0;
  border-bottom: 0;
  font-size: clamp(22px, 3vw, 30px);
}

.page-about .boundary__text {
  margin: 0 0 12px;
  max-width: 74ch;
  font-size: 15px;
  line-height: 1.9;
  color: var(--muted);
}

.page-about .boundary__text:last-child {
  margin-bottom: 0;
}

@media (min-width: 861px) {
  .page-about .boundary {
    padding: 32px 34px 30px;
  }
}

/* ============ 本地化与备案 ============ */
.page-about .local__text {
  margin: 0 0 16px;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.9;
  color: var(--muted);
}

.page-about .local-contacts {
  margin: 0;
  border-top: 1px solid var(--line);
}

.page-about .local-contacts .contact-item {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .local-contacts .contact-label {
  margin: 0;
  font-size: 13px;
  color: var(--muted);
}

.page-about .local-contacts .contact-value {
  margin: 0;
  font-size: 14.5px;
  color: var(--white);
  word-break: break-word;
}

.page-about .copy-inline {
  appearance: none;
  -webkit-appearance: none;
  background: none;
  border: 0;
  padding: 0;
  font: inherit;
  color: inherit;
  text-align: left;
  cursor: pointer;
  border-bottom: 1px dashed var(--about-rule-soft);
}

.page-about .copy-inline:hover,
.page-about .copy-inline:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.page-about .copy-inline.is-copied {
  color: var(--pos);
  border-bottom-color: var(--pos);
}

.page-about .local-figure {
  margin: 32px 0 0;
  border: 1px solid var(--line);
}

.page-about .local-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.85);
}

.page-about .local-figure__cap {
  display: block;
  padding: 9px 14px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  color: var(--muted);
}

.page-about .local__foot {
  margin: 18px 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--muted);
}

@media (min-width: 561px) {
  .page-about .local-contacts .contact-item {
    grid-template-columns: 148px minmax(0, 1fr);
    gap: 12px;
    align-items: baseline;
  }
}

/* ============ 外部记录 ============ */
.page-about .records {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .records__item {
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .records__mark {
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--cyan);
}

.page-about .records__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .records__note {
  margin: 20px 0 0;
  max-width: 78ch;
  font-size: 13.5px;
  line-height: 1.85;
  color: var(--muted);
}

@media (min-width: 721px) {
  .page-about .records__item {
    grid-template-columns: 150px minmax(0, 1fr);
    gap: 24px;
    align-items: baseline;
  }
}

/* ============ 继续查阅 ============ */
.page-about .about-next {
  padding: 56px 0 8px;
}

.page-about .next-title {
  margin: 0 0 18px;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 20px;
  line-height: 1.5;
  color: var(--white);
}

.page-about .about-next__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  border-top: 1px solid var(--line);
}

.page-about .about-next__list .index-list__item {
  padding: 15px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-next__list a {
  display: block;
  color: var(--white);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  line-height: 1.6;
  transition: color 0.15s ease;
}

.page-about .about-next__list a:hover,
.page-about .about-next__list a:focus-visible {
  color: var(--cyan);
}

@media (min-width: 721px) {
  .page-about .about-next__list {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }

  .page-about .about-next__list .index-list__item {
    padding: 18px 16px;
    border-bottom: 0;
  }

  .page-about .about-next__list .index-list__item + .index-list__item {
    border-left: 1px solid var(--line);
  }

  .page-about .about-next__list .index-list__item:first-child {
    padding-left: 0;
  }
}