.page-about {
  --about-line: rgba(40, 64, 58, 0.85);
  --about-panel: rgba(22, 48, 42, 0.68);
  --about-panel-deep: rgba(11, 31, 26, 0.9);
  --sec-accent: var(--flare-orange);
  background: var(--ink-green-900);
  color: var(--bone-85);
  padding-bottom: 72px;
}

.page-about .about-crumbs {
  padding-top: 20px;
}

.page-about .about-rail {
  letter-spacing: 0.04em;
}

/* ---------- 栅格基座 ---------- */

.page-about .grid-12 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.page-about .span-4,
.page-about .span-5,
.page-about .span-7,
.page-about .span-8 {
  grid-column: 1 / -1;
  min-width: 0;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding: 26px 0 0;
}

.page-about .about-hero__grid {
  align-items: start;
}

.page-about .about-hero__title {
  margin: 12px 0 16px;
  font-size: clamp(30px, 7.6vw, 54px);
  line-height: 1.08;
  letter-spacing: -0.015em;
  color: var(--bone-050);
}

.page-about .about-hero__lead {
  max-width: 34em;
  color: var(--bone-70);
}

.page-about .about-hero__facts {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--about-line);
  border: 1px solid var(--about-line);
}

.page-about .about-hero__facts li {
  background: var(--moss-800);
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-hero__num {
  font-size: 28px;
  line-height: 1;
  font-weight: 700;
  color: var(--flare-orange);
  letter-spacing: -0.02em;
}

.page-about .about-hero__facts li:nth-child(2) .about-hero__num {
  color: var(--volt-blue);
}

.page-about .about-hero__facts li:nth-child(3) .about-hero__num {
  color: var(--verdict-yellow);
}

.page-about .about-hero__facts li:nth-child(4) .about-hero__num {
  color: var(--bone-050);
}

.page-about .about-hero__label {
  font-size: 13px;
  color: var(--bone-45);
  letter-spacing: 0.04em;
}

.page-about .about-hero__toc {
  border: 1px solid var(--about-line);
  background: linear-gradient(180deg, var(--about-panel) 0%, var(--about-panel-deep) 100%);
  padding: 18px 18px 20px;
}

.page-about .about-hero__toc-kicker {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--volt-blue);
}

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

.page-about .about-hero__toc-list li {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 7px 0;
  border-bottom: 1px dashed var(--grid-line);
  font-size: 15px;
  color: var(--bone-85);
}

.page-about .about-hero__toc-list li:last-child {
  border-bottom: 0;
}

.page-about .about-hero__toc-list .num {
  font-size: 12px;
  color: var(--bone-45);
}

.page-about .about-hero__toc-note {
  margin: 14px 0 0;
  font-size: 13px;
  line-height: 1.6;
  color: var(--bone-45);
}

.page-about .about-hero__media {
  margin: 30px 0 0;
}

/* ---------- 章节通用 ---------- */

.page-about .about-sec {
  position: relative;
  padding: 46px 0 6px;
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.page-about .about-sec .wrap {
  position: relative;
  z-index: 1;
}

.page-about .section-band {
  margin-bottom: 22px;
}

.page-about .section-head {
  display: grid;
  gap: 10px;
  margin: 0 0 26px;
  max-width: 60ch;
}

.page-about .section-head__index {
  margin: 0;
  font-size: clamp(30px, 5.4vw, 44px);
  line-height: 1;
  font-weight: 700;
  color: var(--sec-accent);
  letter-spacing: -0.02em;
}

.page-about .section-head__title {
  margin: 0;
  color: var(--bone-050);
  font-size: clamp(23px, 4.6vw, 36px);
  line-height: 1.16;
}

.page-about .section-head__note {
  margin: 0;
  font-size: 15px;
  line-height: 1.6;
  color: var(--bone-45);
  max-width: 40em;
}

.page-about .about-sec--origin { --sec-accent: var(--flare-orange); }
.page-about .about-sec--timeline { --sec-accent: var(--volt-blue); }
.page-about .about-sec--method { --sec-accent: var(--clay-600); }
.page-about .about-sec--archive { --sec-accent: var(--verdict-yellow); }
.page-about .about-sec--team { --sec-accent: var(--volt-blue); }
.page-about .about-sec--upkeep { --sec-accent: var(--flare-orange); }

/* ---------- 01 缘起 ---------- */

.page-about .origin-text p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.62;
  color: var(--bone-85);
  max-width: 40em;
}

.page-about .origin-text p:last-child {
  margin-bottom: 0;
}

.page-about .origin-aside__box {
  border: 1px solid var(--about-line);
  border-left: 3px solid var(--flare-orange);
  background: var(--about-panel);
  padding: 16px 18px 18px;
}

.page-about .origin-spec {
  margin: 12px 0 0;
}

.page-about .origin-spec dt {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--volt-blue);
  padding-top: 12px;
  border-top: 1px solid var(--grid-line);
}

.page-about .origin-spec dt:first-of-type {
  border-top: 0;
  padding-top: 0;
}

.page-about .origin-spec dd {
  margin: 6px 0 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--bone-70);
}

.page-about .origin-aside__note {
  margin: 16px 0 0;
  padding-top: 12px;
  border-top: 1px dashed var(--grid-line);
  font-size: 13px;
  line-height: 1.6;
  color: var(--bone-45);
}

/* ---------- 02 横向时间轴 ---------- */

.page-about .about-sec--timeline::before {
  content: "2014—2025";
  position: absolute;
  right: 0;
  bottom: -6px;
  z-index: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(54px, 12vw, 96px);
  line-height: 0.82;
  letter-spacing: -0.03em;
  color: var(--bone-050);
  opacity: 0.07;
  white-space: nowrap;
  pointer-events: none;
}

.page-about .tl-strip {
  overflow-x: auto;
  overflow-y: hidden;
  padding: 4px 0 22px;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
  outline-offset: 6px;
}

.page-about .tl-strip:focus-visible {
  outline: 2px solid var(--volt-blue);
}

.page-about .tl-list {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 40px 0 0;
  display: flex;
  gap: 16px;
  min-width: max-content;
}

.page-about .tl-list::before {
  content: "";
  position: absolute;
  top: 20px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--about-line);
}

.page-about .tl-item {
  position: relative;
  flex: 0 0 246px;
  scroll-snap-align: start;
  background: var(--moss-800);
  border: 1px solid var(--about-line);
  border-top: 3px solid var(--flare-orange);
  padding: 18px 16px 20px;
  min-height: 208px;
  transition: background 180ms linear, border-color 180ms linear;
}

.page-about .tl-item--clay {
  border-top-color: var(--clay-600);
}

.page-about .tl-item::before {
  content: "";
  position: absolute;
  top: -26px;
  left: 16px;
  width: 11px;
  height: 11px;
  background: var(--flare-orange);
}

.page-about .tl-item--clay::before {
  background: var(--clay-600);
}

.page-about .tl-item:hover,
.page-about .tl-item:focus-within {
  background: #1B3A32;
  border-color: var(--sec-accent);
}

.page-about .tl-item__year {
  display: block;
  font-size: 30px;
  line-height: 1;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--bone-050);
}

.page-about .tl-item__kind {
  display: block;
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--bone-45);
}

.page-about .tl-item__title {
  margin: 12px 0 8px;
  font-size: 17px;
  line-height: 1.34;
  color: var(--bone-050);
  font-weight: 700;
}

.page-about .tl-item__desc {
  margin: 0;
  font-size: 13px;
  line-height: 1.62;
  color: var(--bone-70);
}

.page-about .about-legend {
  margin-top: 6px;
}

/* ---------- 03 数据方法 ---------- */

.page-about .method-grid {
  align-items: start;
}

.page-about .method-figure {
  margin: 0 0 18px;
}

.page-about .method-card {
  border: 1px solid var(--about-line);
  border-left: 3px solid var(--sec-accent);
  background: var(--about-panel);
  padding: 16px 18px 18px;
  margin-bottom: 12px;
}

.page-about .method-card:last-of-type {
  margin-bottom: 0;
}

.page-about .method-card__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.page-about .method-card__title {
  margin: 0;
  font-size: 19px;
  line-height: 1.3;
  color: var(--bone-050);
  font-weight: 800;
}

.page-about .method-card__specs {
  margin: 0;
}

.page-about .method-card__specs dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--sec-accent);
  margin-top: 12px;
}

.page-about .method-card__specs dt:first-of-type {
  margin-top: 0;
}

.page-about .method-card__specs dd {
  margin: 5px 0 0;
  font-size: 14px;
  line-height: 1.62;
  color: var(--bone-70);
}

.page-about .method-note {
  margin-top: 12px;
  border: 1px dashed var(--about-line);
  background: var(--about-panel-deep);
  padding: 16px 18px;
}

.page-about .method-note p {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.62;
  color: var(--bone-70);
}

/* ---------- 04 档案索引 ---------- */

.page-about .archive-node {
  border: 1px solid var(--about-line);
  background: var(--about-panel);
  margin-bottom: 8px;
}

.page-about .archive-node--l2 {
  margin-left: 16px;
}

.page-about .archive-node--l3 {
  margin-left: 32px;
}

.page-about .archive-node__sum {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 13px 16px;
  cursor: pointer;
  list-style: none;
  font-size: 15px;
  color: var(--bone-050);
}

.page-about .archive-node__sum::-webkit-details-marker {
  display: none;
}

.page-about .archive-node__sum::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--sec-accent);
}

.page-about .archive-node[open] > .archive-node__sum::after {
  content: "−";
}

.page-about .archive-node__sum:focus-visible {
  outline: 2px solid var(--volt-blue);
  outline-offset: 2px;
}

.page-about .archive-node__lv {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--sec-accent);
}

.page-about .archive-node__name {
  font-weight: 700;
}

.page-about .archive-node__count {
  margin-left: auto;
  font-size: 13px;
  color: var(--bone-45);
}

.page-about .archive-node[open] > .archive-node__sum::after {
  margin-left: 0;
}

.page-about .archive-node__sum::after {
  order: 9;
}

.page-about .archive-node__body {
  padding: 0 16px 16px;
  border-top: 1px solid var(--grid-line);
}

.page-about .archive-node__body p {
  margin: 14px 0 0;
  font-size: 14px;
  line-height: 1.62;
  color: var(--bone-70);
  max-width: 42em;
}

.page-about .archive-seasons {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.page-about .archive-seasons li {
  font-family: var(--font-mono);
  font-size: 13px;
  padding: 4px 9px;
  border: 1px solid var(--about-line);
  color: var(--bone-70);
  font-variant-numeric: tabular-nums;
}

.page-about .archive-facets {
  margin-top: 16px;
  padding-top: 14px;
  border-top: 1px dashed var(--grid-line);
}

.page-about .archive-chips {
  margin-top: 8px;
}

.page-about .archive-chips .chip {
  cursor: default;
}

/* ---------- 05 团队分工 ---------- */

.page-about .team-grid {
  align-items: start;
}

.page-about .team-figure {
  margin: 0 0 18px;
}

.page-about .team-detail__lead {
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.62;
  color: var(--bone-70);
  max-width: 38em;
}

.page-about .team-bar {
  display: flex;
  height: 14px;
  border: 1px solid var(--about-line);
  margin-bottom: 20px;
}

.page-about .team-bar__seg {
  display: block;
  height: 100%;
}

.page-about .team-bar__seg--a { width: 58.34%; background: var(--flare-orange); }
.page-about .team-bar__seg--b { width: 25%; background: var(--volt-blue); }
.page-about .team-bar__seg--c { width: 16.66%; background: var(--clay-600); }

.page-about .team-roles {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .team-roles__item {
  display: flex;
  gap: 16px;
  padding: 16px 0;
  border-top: 1px solid var(--grid-line);
}

.page-about .team-roles__item:last-child {
  border-bottom: 1px solid var(--grid-line);
}

.page-about .team-roles__n {
  flex: 0 0 auto;
  min-width: 2.6ch;
  font-size: 30px;
  line-height: 1;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.page-about .team-roles__item--a .team-roles__n { color: var(--flare-orange); }
.page-about .team-roles__item--b .team-roles__n { color: var(--volt-blue); }
.page-about .team-roles__item--c .team-roles__n { color: var(--clay-600); }

.page-about .team-roles__k {
  margin: 0 0 6px;
  font-size: 16px;
  color: var(--bone-050);
  font-weight: 700;
}

.page-about .team-roles__item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.62;
  color: var(--bone-70);
  max-width: 34em;
}

/* ---------- 06 维护与纠错 ---------- */

.page-about .upkeep-grid {
  display: grid;
  gap: 26px;
}

.page-about .upkeep-col__title {
  margin: 0 0 14px;
  font-size: 16px;
  letter-spacing: 0.04em;
  color: var(--bone-050);
  padding-bottom: 10px;
  border-bottom: 2px solid var(--sec-accent);
}

.page-about .upkeep-steps {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .upkeep-steps li {
  padding: 14px 0;
  border-bottom: 1px dashed var(--grid-line);
}

.page-about .upkeep-steps li:last-child {
  border-bottom: 0;
}

.page-about .upkeep-steps__time {
  display: block;
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--volt-blue);
}

.page-about .upkeep-steps li p {
  margin: 6px 0 0;
  font-size: 14px;
  line-height: 1.62;
  color: var(--bone-70);
  max-width: 34em;
}

.page-about .upkeep-flow {
  list-style: none;
  counter-reset: flow;
  margin: 0;
  padding: 0;
  position: relative;
}

.page-about .upkeep-flow li {
  counter-increment: flow;
  position: relative;
  padding: 0 0 18px 46px;
}

.page-about .upkeep-flow li::before {
  content: counter(flow, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 2px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--flare-orange);
}

.page-about .upkeep-flow li::after {
  content: "";
  position: absolute;
  left: 8px;
  top: 20px;
  bottom: 2px;
  width: 1px;
  background: var(--grid-line);
}

.page-about .upkeep-flow li:last-child {
  padding-bottom: 0;
}

.page-about .upkeep-flow li:last-child::after {
  display: none;
}

.page-about .upkeep-flow__k {
  display: block;
  margin-bottom: 4px;
  font-size: 15px;
  font-weight: 700;
  color: var(--bone-050);
}

.page-about .upkeep-flow li p {
  margin: 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--bone-70);
  max-width: 32em;
}

.page-about .upkeep-related {
  margin-top: 34px;
  padding-top: 22px;
  border-top: 1px solid var(--grid-line);
}

.page-about .upkeep-related__note {
  margin: 0 0 14px;
  font-size: 14px;
  color: var(--bone-45);
}

.page-about .upkeep-related__links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 响应式 ---------- */

@media (min-width: 620px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .upkeep-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (min-width: 860px) {
  .page-about {
    padding-bottom: 96px;
  }

  .page-about .about-crumbs {
    padding-top: 26px;
  }

  .page-about .grid-12 {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    gap: var(--col-gap);
  }

  .page-about .span-4 { grid-column: span 4; }
  .page-about .span-5 { grid-column: span 5; }
  .page-about .span-7 { grid-column: span 7; }
  .page-about .span-8 { grid-column: span 8; }

  .page-about .about-hero__media {
    margin-top: 40px;
  }

  .page-about .about-sec {
    padding: 68px 0 10px;
  }

  .page-about .section-head {
    gap: 12px;
    margin-bottom: 34px;
  }

  .page-about .origin-grid {
    align-items: start;
  }

  .page-about .origin-aside {
    padding-top: 4px;
  }

  .page-about .method-figure {
    margin-bottom: 0;
    position: sticky;
    top: calc(var(--header-h) + 28px);
  }

  .page-about .team-figure {
    margin-bottom: 0;
  }

  .page-about .tl-item {
    flex: 0 0 268px;
    min-height: 226px;
  }

  .page-about .upkeep-grid {
    gap: 40px;
  }
}

@media (min-width: 1180px) {
  .page-about .about-hero__grid {
    column-gap: 40px;
  }

  .page-about .about-sec--timeline::before {
    bottom: 0;
  }

  .page-about .method-list {
    padding-left: 12px;
  }
}
<<<END>>>