.page-about {
  --about-gap: clamp(56px, 8vw, 92px);
  --about-hairline: 1px solid rgba(127, 178, 196, .3);
  --about-hairline-gold: 1px solid rgba(201, 154, 75, .34);
  --about-drawer-tex:
    repeating-linear-gradient(90deg, rgba(28, 22, 17, .055) 0 1px, transparent 1px 88px),
    repeating-linear-gradient(180deg, rgba(201, 154, 75, .16) 0 1px, transparent 1px 13px);
  display: block;
  padding-bottom: clamp(48px, 7vw, 84px);
}

.page-about .about-section { padding-top: var(--about-gap); }
.page-about .about-section__lede {
  margin: 22px 0 0;
  max-width: 66ch;
  font-size: 16px;
  line-height: 1.9;
  color: var(--ink);
}
.page-about .about-link {
  color: var(--cold);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
.page-about .about-link:hover,
.page-about .about-link:focus-visible { color: var(--orange-paper); }

/* —— 面包屑 —— */
.page-about .breadcrumb { padding-top: 20px; }
.page-about .breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-label);
  font-size: 13px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--muted);
}
.page-about .breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  margin-right: 8px;
  color: var(--cold-light);
}
.page-about .breadcrumb__link { color: var(--muted); text-decoration: none; }
.page-about .breadcrumb__link:hover,
.page-about .breadcrumb__link:focus-visible { color: var(--cold); text-decoration: underline; }

/* —— 封面 —— */
.page-about .about-cover { padding-top: 26px; }
.page-about .about-cover__inner {
  display: grid;
  gap: 18px;
  padding-bottom: clamp(28px, 4vw, 44px);
  border-bottom: 1px solid rgba(28, 22, 17, .22);
}
.page-about .about-cover__eyebrow {
  margin: 0;
  font-family: var(--font-label);
  font-size: 13px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--ochre);
}
.page-about .about-cover__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(34px, 7.4vw, 64px);
  line-height: 1.06;
  letter-spacing: -.01em;
  font-weight: 700;
  color: var(--ink);
}
.page-about .about-cover__lede {
  margin: 0;
  max-width: 60ch;
  font-size: clamp(16px, 2.2vw, 18px);
  line-height: 1.9;
  color: var(--ink);
}
.page-about .about-cover__sub {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}
.page-about .about-cover__meta {
  display: grid;
  gap: 1px;
  margin: 6px 0 0;
  padding: 0;
  list-style: none;
  background: rgba(127, 178, 196, .3);
  border-top: var(--about-hairline);
  border-bottom: var(--about-hairline);
}
.page-about .about-cover__meta > li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 6px;
  background: var(--paper);
  min-width: 0;
}
.page-about .about-meta__k {
  font-family: var(--font-label);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--muted);
}
.page-about .about-meta__v { font-size: 15px; color: var(--cold); }

.page-about .about-cover__index {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 10px;
  margin-top: 6px;
}
.page-about .about-cover__index a {
  display: inline-block;
  padding: 7px 14px;
  border: var(--about-hairline);
  border-radius: var(--radius-pill);
  font-family: var(--font-label);
  font-size: 12px;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--ink);
  text-decoration: none;
}
.page-about .about-cover__index a:hover,
.page-about .about-cover__index a:focus-visible {
  background: var(--cold);
  border-color: var(--cold);
  color: var(--paper);
}

/* —— 分区题头 —— */
.page-about .section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 16px;
  padding-top: 16px;
  border-top: 2px solid var(--ink);
}
.page-about .section-head__index {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--cold);
}
.page-about .section-head__title {
  margin: 0;
  flex: 1 1 auto;
  min-width: 0;
  font-family: var(--font-display);
  font-size: clamp(23px, 4vw, 34px);
  line-height: 1.2;
  font-weight: 700;
  color: var(--ink);
}
.page-about .copy-btn {
  margin-left: auto;
  padding: 6px 12px;
  border: var(--about-hairline);
  border-radius: var(--radius-pill);
  background: transparent;
  font-family: var(--font-label);
  font-size: 11px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--cold);
  cursor: pointer;
}
.page-about .copy-btn:hover,
.page-about .copy-btn:focus-visible { background: var(--cold); color: var(--paper); border-color: var(--cold); }

/* —— 01 口径缘起 —— */
.page-about .about-origin__grid {
  display: grid;
  gap: 26px;
  margin-top: 26px;
}
.page-about .about-origin__text p { margin: 0 0 1.05em; }
.page-about .about-origin__text p:last-child { margin-bottom: 0; }
.page-about .prose p {
  font-size: 16px;
  line-height: 1.9;
  color: var(--ink);
  max-width: 40ch;
}
.page-about .note {
  font-size: 13px;
  line-height: 1.8;
  color: var(--muted);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  max-width: 56ch;
}
.page-about .about-drawer {
  position: relative;
  border-radius: var(--radius-lg);
  border: var(--about-hairline-gold);
  overflow: hidden;
  margin: 0;
  background-image: var(--about-drawer-tex);
}
.page-about .media-frame__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}
.page-about .media-frame__tag {
  position: absolute;
  left: 14px;
  bottom: 14px;
  padding: 5px 11px;
  border-radius: var(--radius-pill);
  background: rgba(28, 22, 17, .72);
  color: var(--sand-light);
  font-size: 11px;
  letter-spacing: .12em;
}
.page-about .about-drawer .media-frame__img { opacity: .88; mix-blend-mode: multiply; }

/* —— 02 三级数据骨架 —— */
.page-about .about-tiers {
  display: grid;
  gap: 16px;
  margin-top: 26px;
}
.page-about .about-tier {
  min-width: 0;
  padding: 20px 18px;
  border: var(--about-hairline);
  border-radius: var(--radius-md);
  background: var(--paper);
  transition: background-color 180ms var(--ease), border-color 180ms var(--ease);
}
.page-about .about-tier:hover,
.page-about .about-tier:focus-within,
.page-about .about-tier:focus {
  background: var(--sand-light);
  border-color: rgba(140, 74, 36, .38);
  outline: none;
}
.page-about .about-tier__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding-bottom: 12px;
  border-bottom: var(--about-hairline-gold);
}
.page-about .about-tier__no {
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--orange-paper);
}
.page-about .about-tier__name {
  margin: 0;
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 600;
  color: var(--ink);
}
.page-about .about-tier__fields { margin: 0; }
.page-about .about-tier__row {
  display: grid;
  gap: 4px;
  padding: 11px 0;
  border-bottom: var(--about-hairline);
}
.page-about .about-tier__row:last-child { border-bottom: 0; }
.page-about .about-tier__row dt {
  font-family: var(--font-label);
  font-size: 12px;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--muted);
}
.page-about .about-tier__row dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--ink);
}

/* —— 03 分区归并规则 —— */
.page-about .about-zoning__grid {
  display: grid;
  gap: 28px;
  margin-top: 26px;
}
.page-about .about-rules {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: var(--about-hairline);
}
.page-about .about-rules__item {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 14px;
  padding: 16px 0;
  border-bottom: var(--about-hairline);
}
.page-about .about-rules__no {
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--cold);
}
.page-about .about-rules__item p {
  margin: 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink);
  max-width: 46ch;
}
.page-about .about-sample {
  align-self: start;
  padding: 20px 18px;
  border: var(--about-hairline-gold);
  border-radius: var(--radius-md);
  background: var(--paper-2);
}
.page-about .about-sample__cap {
  margin: 0 0 14px;
  font-family: var(--font-label);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--ochre);
}
.page-about .about-sample .note { margin: 14px 0 0; }

.page-about .data-row {
  display: grid;
  gap: 6px;
  padding: 14px 4px;
  border-top: var(--about-hairline);
  border-bottom: var(--about-hairline);
  min-height: 52px;
  align-items: baseline;
}
.page-about .data-row__index { font-size: 14px; color: var(--cold); letter-spacing: .06em; }
.page-about .data-row__body { font-size: 15px; line-height: 1.7; color: var(--ink); }
.page-about .data-row__range { font-size: 15px; color: var(--orange-paper); }

/* —— 04 版本演进 —— */
.page-about .about-versionmap {
  position: relative;
  margin: 26px 0 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: var(--about-hairline);
}
.page-about .about-timeline {
  position: relative;
  margin: 32px 0 0;
  padding: 0;
  list-style: none;
}
.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: linear-gradient(180deg,
    rgba(201, 154, 75, .2) 0%,
    var(--sand) 10%,
    var(--sand) 86%,
    rgba(201, 154, 75, .2) 100%);
}
.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 20px 30px;
}
.page-about .about-timeline__item:last-child { padding-bottom: 0; }
.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 22px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  border: 1px solid var(--sand);
  background: var(--paper);
}
.page-about .about-timeline__item--current::before {
  background: var(--sand);
  box-shadow: 0 0 0 4px rgba(201, 154, 75, .22);
}
.page-about .about-version {
  border: var(--about-hairline);
  border-radius: var(--radius-md);
  background: var(--paper);
  transition: border-color 200ms var(--ease), background-color 200ms var(--ease);
}
.page-about .about-version[open] {
  border-color: rgba(201, 154, 75, .6);
  background: rgba(235, 211, 163, .3);
}
.page-about .about-version__sum {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 14px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
}
.page-about .about-version__sum::-webkit-details-marker { display: none; }
.page-about .about-version__sum::after {
  content: "展开";
  margin-left: auto;
  font-family: var(--font-label);
  font-size: 11px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--cold);
}
.page-about .about-version[open] .about-version__sum::after { content: "收起"; }
.page-about .about-version__sum:focus-visible {
  outline: 2px solid var(--cold);
  outline-offset: 2px;
}
.page-about .about-version__code {
  font-size: 14px;
  letter-spacing: .08em;
  color: var(--cold);
}
.page-about .about-version__title {
  margin: 0;
  flex: 1 1 190px;
  min-width: 0;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 600;
  line-height: 1.45;
  color: var(--ink);
}
.page-about .about-version__period {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--muted);
}
.page-about .about-version__body {
  padding: 0 18px 20px;
}
.page-about .about-version__body > p {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink);
  max-width: 60ch;
}
.page-about .about-changebar {
  display: flex;
  gap: 1px;
  margin: 0 0 6px;
  border: var(--about-hairline);
  border-radius: var(--radius-pill);
  overflow: hidden;
}
.page-about .about-changebar__seg {
  flex: 1 1 0;
  min-width: 0;
  padding: 7px 8px;
  text-align: center;
  font-family: var(--font-label);
  font-size: 11px;
  letter-spacing: .12em;
  white-space: nowrap;
}
.page-about .about-changebar__seg--add { background: rgba(30, 107, 132, .16); color: var(--cold); }
.page-about .about-changebar__seg--mod { background: rgba(224, 118, 43, .18); color: var(--orange-paper); }
.page-about .about-changebar__seg--dep { background: rgba(107, 96, 85, .14); color: var(--muted); }
.page-about .about-changes {
  margin: 0;
  padding: 0;
  list-style: none;
}
.page-about .about-changes__item {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 12px;
  padding: 10px 0;
  border-bottom: var(--about-hairline);
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink);
}
.page-about .about-changes__item:last-child { border-bottom: 0; }
.page-about .about-changes__tag {
  flex: 0 0 auto;
  padding: 3px 9px;
  border: 1px solid currentColor;
  border-radius: var(--radius-pill);
  font-size: 11px;
  letter-spacing: .1em;
}
.page-about .about-changes__item--add .about-changes__tag { color: var(--cold); }
.page-about .about-changes__item--mod .about-changes__tag { color: var(--orange-paper); }
.page-about .about-changes__item--dep .about-changes__tag { color: var(--muted); }

/* —— 05 维护分工 —— */
.page-about .about-maintain__grid {
  display: grid;
  gap: 28px;
  margin-top: 26px;
}
.page-about .about-maintain__total {
  margin: 0 0 20px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink);
  max-width: 46ch;
}
.page-about .about-maintain__total .mono { color: var(--cold); font-size: 1.05em; }
.page-about .about-teams {
  display: grid;
  gap: 14px;
  margin-bottom: 26px;
}
.page-about .about-team {
  min-width: 0;
  padding: 16px 16px 18px;
  border: var(--about-hairline);
  border-left: 3px solid var(--sand);
  border-radius: var(--radius-md);
  background: var(--paper);
}
.page-about .about-team__no {
  margin: 0 0 6px;
  font-size: 13px;
  letter-spacing: .1em;
  color: var(--ochre);
}
.page-about .about-team__name {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 600;
  color: var(--ink);
}
.page-about .about-team p:last-child {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink);
}
.page-about .about-subhead {
  margin: 0 0 12px;
  font-family: var(--font-label);
  font-size: 14px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--ochre);
}
.page-about .about-review {
  margin: 0 0 18px;
  padding: 0;
  list-style: none;
  counter-reset: none;
}
.page-about .about-review li {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 12px;
  align-items: baseline;
  min-height: 44px;
  padding: 11px 0;
  border-bottom: var(--about-hairline);
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink);
}
.page-about .about-review li:first-child { border-top: var(--about-hairline); }
.page-about .about-review__no { font-size: 13px; color: var(--cold); }
.page-about .about-maintain__text > p {
  margin: 0 0 1em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink);
  max-width: 46ch;
}
.page-about .about-teamnap {
  position: relative;
  align-self: start;
  margin: 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: var(--about-hairline);
}

/* —— 页脚法务条 —— */
.page-about .about-legal {
  margin-top: var(--about-gap);
  padding-top: 22px;
  border-top: var(--about-hairline-gold);
  display: grid;
  gap: 10px;
}
.page-about .about-legal .note { max-width: 70ch; }
.page-about .about-legal__row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 20px;
  margin: 4px 0 0;
  font-size: 13px;
  color: var(--muted);
}

/* —— 平板与桌面 —— */
@media (min-width: 700px) {
  .page-about .about-cover__meta { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .page-about .about-tiers { gap: 1px; background: rgba(127, 178, 196, .3); border: var(--about-hairline); border-radius: var(--radius-md); overflow: hidden; }
  .page-about .about-tier { border: 0; border-radius: 0; }
  .page-about .about-teams { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1px; background: rgba(127, 178, 196, .3); }
  .page-about .about-team { border-radius: 0; border-left: 0; border-top: 3px solid var(--sand); }
}

@media (min-width: 1000px) {
  .page-about .about-cover__meta { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .page-about .about-origin__grid { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); gap: 40px; align-items: start; }
  .page-about .about-zoning__grid { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); gap: 44px; }
  .page-about .about-maintain__grid { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); gap: 44px; }
  .page-about .about-timeline { padding-left: 8px; }
  .page-about .about-timeline__item { padding-left: 40px; padding-bottom: 26px; }
  .page-about .about-timeline__item::before { top: 24px; left: 0; width: 12px; height: 12px; }
  .page-about .about-version__body { padding-left: 24px; padding-right: 24px; }
  .page-about .about-version__sum { padding: 18px 24px; }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-tier,
  .page-about .about-version { transition: none; }
}
</style>