.page-about {
  --about-gap: clamp(20px, 4vw, 40px);
  --about-hair: 1px solid rgba(201, 210, 216, .95);
  background: var(--paper);
  color: var(--brown);
  font-family: var(--font-body);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  background: var(--abyss);
  color: var(--cream);
  padding: clamp(22px, 4vw, 44px) 0 clamp(40px, 7vw, 84px);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 3px;
  background: linear-gradient(180deg, var(--cyan), rgba(35, 211, 211, 0));
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan) 0%, rgba(35, 211, 211, .18) 58%, rgba(35, 211, 211, 0) 100%);
}

.page-about .about-hero .breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
  font-size: 13px;
}

.page-about .about-hero .breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  margin-right: 8px;
  color: rgba(245, 240, 230, .45);
}

.page-about .about-hero .breadcrumb-link {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color .2s ease;
}

.page-about .about-hero .breadcrumb-link:hover,
.page-about .about-hero .breadcrumb-link:focus-visible {
  border-bottom-color: var(--cyan);
}

.page-about .about-hero .breadcrumb-current {
  color: rgba(245, 240, 230, .82);
}

.page-about .about-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 5vw, 48px);
  margin-top: clamp(20px, 3.5vw, 34px);
  align-items: end;
}

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

.page-about .about-hero .eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--cyan);
  border: 1px solid rgba(35, 211, 211, .38);
  border-radius: 999px;
  padding: 4px 12px;
  margin: 0 0 18px;
}

.page-about .about-title {
  font-family: var(--font-head);
  font-weight: 800;
  letter-spacing: -.01em;
  line-height: 1.24;
  font-size: clamp(30px, 4.4vw, 50px);
  color: var(--cream);
  margin: 0 0 .55em;
  max-width: 20ch;
}

.page-about .about-lede {
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.85;
  color: rgba(245, 240, 230, .82);
  max-width: 40ch;
  margin: 0 0 22px;
}

.page-about .hero-points {
  list-style: none;
  margin: 0 0 26px;
  padding: 0;
  display: grid;
  gap: 8px;
  font-size: 14px;
  color: rgba(245, 240, 230, .74);
}

.page-about .hero-points li {
  position: relative;
  padding-left: 20px;
}

.page-about .hero-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .62em;
  width: 10px;
  height: 2px;
  background: var(--cyan);
}

.page-about .hero-points .mono {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--cyan);
  letter-spacing: .02em;
}

.page-about .hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-hero .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  border-radius: var(--r-sm);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  transition: transform .18s ease, background-color .18s ease, border-color .18s ease;
}

.page-about .about-hero .btn--gate {
  background: var(--orange);
  color: var(--abyss);
  border: 1px solid var(--orange);
}

.page-about .about-hero .btn--ghost {
  background: transparent;
  color: var(--cream);
  border: 1px solid rgba(245, 240, 230, .38);
}

.page-about .about-hero .btn--gate:hover,
.page-about .about-hero .btn--gate:focus-visible {
  transform: translateY(-2px);
  background: var(--amber);
  border-color: var(--amber);
}

.page-about .about-hero .btn--ghost:hover,
.page-about .about-hero .btn--ghost:focus-visible {
  transform: translateY(-2px);
  border-color: var(--cyan);
  color: var(--cyan);
}

.page-about .about-hero .btn:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 2px;
}

.page-about .about-hero-media {
  margin: 0;
  min-width: 0;
}

.page-about .about-hero-media .figure-media {
  border-radius: var(--r-lg);
  overflow: hidden;
  border: 1px solid rgba(35, 211, 211, .3);
  background: #0e2731;
}

.page-about .about-hero-media .figure-media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .about-hero-media .figure-caption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: rgba(245, 240, 230, .62);
  font-family: var(--font-mono);
  letter-spacing: .01em;
}

/* ---------- 通用章节块 ---------- */
.page-about .section {
  padding: clamp(40px, 7vw, 84px) 0;
}

.page-about .section--tight {
  padding: clamp(24px, 4vw, 44px) 0;
}

.page-about .section--paper {
  background: var(--cream);
}

.page-about .section--cool {
  background: var(--cool);
}

.page-about .section--ink {
  background: var(--abyss);
  color: var(--cream);
}

.page-about .container,
.page-about .container--narrow {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 var(--gutter);
  box-sizing: border-box;
}

.page-about .container--narrow {
  max-width: 820px;
}

.page-about .section-head {
  margin-bottom: clamp(22px, 3.5vw, 38px);
  max-width: 62ch;
}

.page-about .section-title {
  font-family: var(--font-head);
  font-weight: 800;
  letter-spacing: -.01em;
  line-height: 1.28;
  font-size: clamp(22px, 2.8vw, 32px);
  color: var(--abyss);
  margin: 10px 0 0;
}

.page-about .section--ink .section-title {
  color: var(--cream);
}

.page-about .section-note {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: rgba(74, 63, 56, .78);
}

.page-about .section--ink .section-note {
  color: rgba(245, 240, 230, .72);
}

.page-about .archive-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--teal);
  color: var(--cream);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .07em;
  padding: 5px 11px;
  border-radius: 4px;
  border-left: 3px solid var(--cyan);
}

.page-about .archive-chip--light {
  background: rgba(20, 84, 92, .85);
  color: var(--cream);
  border-left-color: var(--amber);
}

.page-about .section p {
  font-size: 16px;
  line-height: 1.85;
  color: var(--brown);
  margin: 0 0 1.2em;
  max-width: 42ch;
}

.page-about .container--narrow p {
  max-width: none;
}

.page-about .section--ink p {
  color: rgba(245, 240, 230, .8);
}

.page-about .about-hero p,
.page-about .about-hero .about-lede {
  max-width: 40ch;
}

/* ---------- 定位区块 ---------- */
.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 44px);
  align-items: start;
}

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

.page-about .about-split-side {
  min-width: 0;
  background: var(--cool);
  border: var(--about-hair);
  border-radius: var(--r-md);
  padding: clamp(18px, 3vw, 26px);
  border-top: 4px solid var(--teal);
}

.page-about .side-title {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17px;
  color: var(--abyss);
  margin: 0 0 16px;
}

.page-about .side-list {
  list-style: none;
  margin: 0 0 14px;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .side-list li {
  display: grid;
  grid-template-columns: minmax(0, 92px) minmax(0, 1fr);
  gap: 12px;
  padding: 11px 0;
  border-bottom: var(--about-hair);
  font-size: 14px;
  line-height: 1.7;
}

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

.page-about .side-key {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--teal);
  letter-spacing: .02em;
}

.page-about .side-val {
  color: var(--brown);
}

.page-about .note {
  font-size: 13px;
  line-height: 1.75;
  color: rgba(74, 63, 56, .72);
  margin: 0;
}

/* ---------- 目录树 ---------- */
.page-about .tree-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
}

.page-about .tree-branch {
  background: var(--cream);
  border: var(--about-hair);
  border-left: 4px solid var(--teal);
  border-radius: var(--r-sm);
  padding: 18px 18px 14px;
  transition: transform .2s ease, box-shadow .2s ease, border-left-color .2s ease;
}

.page-about .tree-branch:hover,
.page-about .tree-branch:focus-within {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lift);
  border-left-color: var(--cyan);
}

.page-about .branch-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 10px;
  padding-bottom: 10px;
  margin-bottom: 10px;
  border-bottom: 1px dashed var(--slate);
}

.page-about .branch-num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--cream);
  background: var(--abyss);
  border-radius: 3px;
  padding: 2px 6px;
}

.page-about .branch-title {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 18px;
  letter-spacing: -.005em;
  color: var(--abyss);
  margin: 0;
  flex: 1 1 auto;
}

.page-about .branch-count {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--teal);
  white-space: nowrap;
}

.page-about .branch-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 7px;
}

.page-about .branch-list li {
  position: relative;
  padding-left: 18px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--brown);
}

.page-about .branch-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .68em;
  width: 11px;
  height: 1px;
  background: var(--cyan);
}

/* ---------- 数字条 ---------- */
.page-about .about-strip {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.page-about .strip-item {
  background: var(--cool);
  border: var(--about-hair);
  border-radius: var(--r-sm);
  padding: 16px 16px 14px;
  display: grid;
  gap: 2px;
  min-width: 0;
}

.page-about .strip-label {
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--teal);
  font-family: var(--font-mono);
}

.page-about .strip-value {
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.4vw, 36px);
  line-height: 1.1;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--abyss);
}

.page-about .strip-unit {
  font-size: 12px;
  color: rgba(74, 63, 56, .7);
}

/* ---------- 查询口径 ---------- */
.page-about .pathway {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 4px 0 26px;
}

.page-about .pathway-step {
  position: relative;
  background: var(--cream);
  border: var(--about-hair);
  border-radius: var(--r-sm);
  padding: 20px 20px 16px;
  padding-left: 56px;
  transition: transform .2s ease, box-shadow .2s ease;
}

.page-about .pathway-step:hover,
.page-about .pathway-step:focus-within {
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
}

.page-about .pathway-index {
  position: absolute;
  left: 18px;
  top: 20px;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  color: var(--cyan);
  border-right: 1px solid var(--slate);
  padding-right: 12px;
  line-height: 1;
}

.page-about .pathway-title {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17px;
  color: var(--abyss);
  margin: 0 0 6px;
}

.page-about .pathway-step p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--brown);
  max-width: none;
}

.page-about .about-callout {
  border-left: 4px solid var(--orange);
  background: var(--cool);
  border-radius: 0 var(--r-sm) var(--r-sm) 0;
  padding: 18px 20px;
}

.page-about .about-callout p {
  margin: 0 0 10px;
  font-size: 15px;
  line-height: 1.8;
  max-width: none;
}

.page-about .about-callout strong {
  color: var(--abyss);
}

.page-about .link-inline {
  display: inline-block;
  color: var(--teal);
  font-size: 14px;
  text-decoration: none;
  border-bottom: 1px solid var(--cyan);
  padding-bottom: 1px;
  transition: color .18s ease, border-color .18s ease;
}

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

.page-about .link-inline--light {
  color: var(--cyan);
  border-bottom-color: rgba(35, 211, 211, .6);
}

.page-about .link-inline--light:hover,
.page-about .link-inline--light:focus-visible {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

/* ---------- 维护机制 ---------- */
.page-about .maintain-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 4vw, 40px);
  align-items: start;
}

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

.page-about .maintain-media .figure-media {
  border-radius: var(--r-md);
  overflow: hidden;
  border: var(--about-hair);
  background: var(--cream);
}

.page-about .maintain-media .figure-media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .maintain-media .figure-caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .02em;
  line-height: 1.7;
  color: rgba(74, 63, 56, .68);
}

.page-about .maintain-body p {
  max-width: 46ch;
}

.page-about .group-list {
  list-style: none;
  margin: 4px 0 22px;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .group-item {
  padding: 14px 0 14px 18px;
  border-bottom: var(--about-hair);
  border-left: 2px solid transparent;
  transition: border-left-color .2s ease, background-color .2s ease;
}

.page-about .group-item:hover,
.page-about .group-item:focus-within {
  border-left-color: var(--cyan);
  background: rgba(35, 211, 211, .06);
}

.page-about .group-name {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 17px;
  color: var(--abyss);
  margin: 0 0 5px;
}

.page-about .group-desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--brown);
  max-width: 46ch;
}

.page-about .cadence {
  border: var(--about-hair);
  border-radius: var(--r-sm);
  background: var(--cream);
  overflow: hidden;
}

.page-about .cadence-row {
  display: grid;
  grid-template-columns: minmax(0, 84px) minmax(0, 1fr);
  gap: 12px;
  align-items: baseline;
  padding: 12px 16px;
  border-bottom: var(--about-hair);
  font-size: 14px;
  line-height: 1.7;
}

.page-about .cadence-row:last-child {
  border-bottom: 0;
}

.page-about .cadence-key {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--cream);
  background: var(--teal);
  border-radius: 3px;
  padding: 2px 7px;
  text-align: center;
  white-space: nowrap;
}

.page-about .cadence-val {
  color: var(--brown);
}

/* ---------- 版本演进 ---------- */
.page-about .version-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 44px);
  align-items: start;
}

.page-about .timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 6px 0 0 30px;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 12px;
  bottom: 12px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan), rgba(35, 211, 211, .12));
}

.page-about .timeline-item {
  position: relative;
  padding: 0 0 24px;
}

.page-about .timeline-item::before {
  content: "";
  position: absolute;
  left: -30px;
  top: 6px;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  background: var(--abyss);
  border: 2px solid var(--cyan);
  box-sizing: border-box;
  transition: border-color .2s ease, background-color .2s ease;
}

.page-about .timeline-item:hover::before,
.page-about .timeline-item:focus-within::before {
  border-color: var(--amber);
}

.page-about .timeline-item.is-current::before {
  border-color: var(--orange);
  background: var(--orange);
  box-shadow: 0 0 0 4px rgba(255, 122, 60, .2);
}

.page-about .tl-stage {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--cyan);
  margin-bottom: 4px;
}

.page-about .timeline-item.is-current .tl-stage {
  color: var(--orange);
}

.page-about .tl-title {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 18px;
  letter-spacing: -.005em;
  color: var(--cream);
  margin: 0 0 6px;
}

.page-about .tl-desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: rgba(245, 240, 230, .74);
  max-width: 42ch;
}

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

.page-about .version-media .figure-media {
  border-radius: var(--r-md);
  overflow: hidden;
  border: 1px solid rgba(35, 211, 211, .28);
  background: #0e2731;
}

.page-about .version-media .figure-media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .version-media .figure-caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .02em;
  line-height: 1.7;
  color: rgba(245, 240, 230, .6);
}

.page-about .version-foot {
  margin: clamp(22px, 3vw, 34px) 0 0;
  font-size: 14px;
  line-height: 1.85;
  color: rgba(245, 240, 230, .78);
  max-width: 56ch;
}

/* ---------- 季度清单 ---------- */
.page-about .quarter-steps {
  list-style: none;
  margin: 0 0 22px;
  padding: 0;
  display: grid;
  gap: 12px;
  counter-reset: none;
}

.page-about .quarter-steps li {
  display: grid;
  grid-template-columns: minmax(0, 40px) minmax(0, 1fr);
  gap: 14px;
  align-items: start;
  padding: 16px 18px;
  background: var(--cool);
  border: var(--about-hair);
  border-radius: var(--r-sm);
  transition: transform .2s ease, box-shadow .2s ease;
}

.page-about .quarter-steps li:hover,
.page-about .quarter-steps li:focus-within {
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
}

.page-about .qs-index {
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  line-height: 1.2;
  color: var(--cyan);
  border-right: 1px solid var(--slate);
  padding-right: 10px;
}

.page-about .qs-title {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 16px;
  color: var(--abyss);
  margin: 0 0 5px;
}

.page-about .quarter-steps p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--brown);
  max-width: none;
}

/* ---------- 相关页面卡片 ---------- */
.page-about .card {
  display: block;
  text-decoration: none;
  background: var(--cream);
  border: var(--about-hair);
  border-radius: var(--r-sm);
  padding: 20px 20px 16px;
  transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}

.page-about .card--archive {
  border-left: 4px solid var(--teal);
}

.page-about .card:hover,
.page-about .card:focus-visible {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lift);
  border-color: var(--cyan);
  outline: none;
}

.page-about .card:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 2px;
}

.page-about .card-title {
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 18px;
  letter-spacing: -.005em;
  color: var(--abyss);
  margin: 0 0 8px;
}

.page-about .card-text {
  font-size: 14px;
  line-height: 1.75;
  color: var(--brown);
  margin: 0 0 12px;
  max-width: none;
}

.page-about .card-meta {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--teal);
  border-top: 1px solid var(--slate);
  padding-top: 8px;
  width: 100%;
}

/* ---------- 视口渐显 ---------- */
.page-about [data-reveal] {
  opacity: 1;
}

@media (prefers-reduced-motion: no-preference) {
  .page-about [data-reveal]:not(.is-visible) {
    opacity: 0;
  }
  .page-about [data-reveal] {
    transition: opacity .26s ease;
  }
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-strip {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .tree-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 880px) {
  .page-about .about-strip {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }
  .page-about .tree-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .pathway {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
  }
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
  }
  .page-about .maintain-grid {
    grid-template-columns: minmax(0, .9fr) minmax(0, 1.1fr);
  }
  .page-about .version-wrap {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
  }
}

@media (min-width: 1024px) {
  .page-about .container--narrow {
    padding: 0 var(--gutter);
  }
  .page-about .about-title {
    max-width: 22ch;
  }
}

@media (max-width: 479px) {
  .page-about .cadence-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 6px;
  }
  .page-about .cadence-key {
    justify-self: start;
  }
  .page-about .side-list li {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
  }
  .page-about .quarter-steps li {
    grid-template-columns: minmax(0, 32px) minmax(0, 1fr);
    gap: 10px;
  }
  .page-about .pathway-step {
    padding-left: 20px;
    padding-top: 44px;
  }
  .page-about .pathway-index {
    left: 20px;
    top: 16px;
    border-right: 0;
    padding-right: 0;
  }
}

.page-about a:focus-visible,
.page-about button:focus-visible,
.page-about [tabindex]:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 2px;
}
<<<END>>>