.page-about {
  --about-gap: clamp(26px, 4vw, 56px);
  --about-tonenum: clamp(1.6rem, 3vw, 2.4rem);
  background: var(--paper-cream);
  color: var(--ink-charcoal);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-block: clamp(18px, 3vw, 34px) clamp(34px, 5vw, 68px);
  border-bottom: var(--rule);
}

.page-about .about-hero-grid {
  display: grid;
  gap: clamp(30px, 5vw, 60px);
  margin-block-start: clamp(22px, 4vw, 42px);
}

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1fr) minmax(220px, 264px);
    align-items: end;
  }
}

.page-about .about-hero-title {
  margin: 0.3em 0 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(2.15rem, 6.6vw, 4.6rem);
  line-height: 1.02;
  letter-spacing: -0.02em;
  max-width: 17ch;
}

.page-about .about-hero-lede {
  margin: 0;
  font-size: clamp(1rem, 1.5vw, 1.1rem);
  line-height: 1.8;
  color: var(--ink-soft);
  max-width: 46ch;
}

.page-about .about-hero-lede {
  margin-block-start: clamp(18px, 3vw, 28px);
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-block-start: clamp(20px, 3vw, 32px);
}

.page-about .about-hero-facts {
  margin: 0;
  padding-block-start: 18px;
  border-top: 2px solid var(--ink-charcoal);
}

.page-about .about-fact {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  padding-block: 9px;
  border-bottom: var(--rule);
}

.page-about .about-fact dt {
  font-size: 12.5px;
  color: var(--neutral-moss);
  letter-spacing: 0.02em;
}

.page-about .about-fact dd {
  margin: 0;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13.5px;
  color: var(--ink-charcoal);
  white-space: nowrap;
}

/* ---------- 索引 + 内容骨架 ---------- */
.page-about .about-index-layout {
  display: grid;
  gap: clamp(28px, 4vw, 48px);
  padding-block: clamp(34px, 6vw, 76px);
}

@media (min-width: 1000px) {
  .page-about .about-index-layout {
    grid-template-columns: 186px minmax(0, 1fr);
    align-items: start;
    gap: clamp(40px, 6vw, 84px);
  }
}

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

.page-about .about-rail-title {
  margin: 0 0 12px;
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--neutral-moss);
  text-transform: uppercase;
}

.page-about .about-rail-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.page-about .about-rail-link {
  display: flex;
  align-items: baseline;
  gap: 9px;
  padding: 6px 9px;
  border-radius: var(--radius);
  font-size: 13px;
  color: var(--ink-soft);
  text-decoration: none;
  transition: background var(--t-fast), color var(--t-fast), border-color var(--t-fast);
}

.page-about .about-rail-link .rail-index {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 11.5px;
  color: var(--neutral-moss);
}

.page-about .about-rail-link:hover {
  background: var(--paper-deep);
  color: var(--ink-charcoal);
}

.page-about .about-rail-link[aria-current="true"] {
  background: var(--card-ivory);
  color: var(--ink-charcoal);
  box-shadow: inset 2px 0 0 var(--grass-primary);
}

.page-about .about-rail-link[aria-current="true"] .rail-index {
  color: var(--grass-primary);
}

.page-about .about-rail-foot {
  margin: 16px 0 0;
  padding-block-start: 14px;
  border-top: var(--rule);
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--neutral-moss);
  max-width: 28ch;
}

@media (min-width: 1000px) {
  .page-about .about-rail {
    position: sticky;
    top: 88px;
  }
  .page-about .about-rail-nav {
    display: grid;
    gap: 2px;
  }
}

.page-about .about-flow {
  display: grid;
  gap: clamp(48px, 7vw, 92px);
  min-width: 0;
}

.page-about .about-block {
  scroll-margin-top: 96px;
  min-width: 0;
}

.page-about .about-block-head {
  max-width: 60ch;
  margin-block-end: clamp(22px, 3.4vw, 40px);
}

.page-about .about-lines-lede {
  margin: 0;
  font-size: clamp(0.98rem, 1.4vw, 1.06rem);
  line-height: 1.8;
  color: var(--ink-soft);
}

.page-about .about-subhead {
  margin: 0 0 12px;
  font-size: 12.5px;
  letter-spacing: 0.1em;
  color: var(--grass-primary);
}

/* ---------- 01 缘起 ---------- */
.page-about .about-origin {
  display: grid;
  gap: clamp(24px, 3.4vw, 44px);
}

@media (min-width: 900px) {
  .page-about .about-origin {
    grid-template-columns: minmax(0, 7fr) minmax(0, 4fr);
    align-items: start;
  }
}

.page-about .about-origin-prose p {
  margin: 0 0 1.15em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink-soft);
  max-width: 62ch;
}

.page-about .about-origin-prose p:last-child {
  margin-block-end: 0;
}

.page-about .about-origin-note {
  padding: 20px 22px;
  background: var(--card-ivory);
  border: var(--rule);
  border-left: 3px solid var(--grass-primary);
  box-shadow: var(--shadow-1);
}

.page-about .about-quote {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(1.05rem, 1.8vw, 1.32rem);
  line-height: 1.6;
  color: var(--ink-charcoal);
}

.page-about .about-quote-note {
  margin: 12px 0 0;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--neutral-moss);
}

/* ---------- 02 三条主线 ---------- */
.page-about .about-block--lines {
  position: relative;
  isolation: isolate;
}

.page-about .about-lines-bg {
  position: absolute;
  inset: -8px -10px;
  z-index: -1;
  overflow: hidden;
  opacity: 0.09;
  -webkit-mask-image: linear-gradient(180deg, transparent, #000 22%, #000 74%, transparent);
  mask-image: linear-gradient(180deg, transparent, #000 22%, #000 74%, transparent);
}

.page-about .about-lines-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.page-about .about-lines {
  display: grid;
  gap: clamp(24px, 3.4vw, 40px);
}

@media (min-width: 1040px) {
  .page-about .about-lines {
    grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
    align-items: start;
  }
}

.page-about .about-lines-claim {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.35rem, 2.4vw, 1.85rem);
  line-height: 1.28;
  letter-spacing: -0.01em;
  max-width: 9em;
}

.page-about .about-line-grid {
  display: grid;
  gap: clamp(22px, 3vw, 34px);
}

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

@media (min-width: 1180px) {
  .page-about .about-line-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.page-about .about-line {
  padding-block-start: 16px;
  border-top: 2px solid var(--ink-charcoal);
}

.page-about .about-line-tag {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--neutral-moss);
}

.page-about .about-line-title {
  margin: 0 0 8px;
  font-size: clamp(1.2rem, 2vw, 1.45rem);
  font-weight: 700;
  line-height: 1.2;
}

.page-about .about-line-ask {
  margin: 0 0 14px;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--grass-primary);
}

.page-about .about-line-points {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 9px;
}

.page-about .about-line-points li {
  position: relative;
  padding-inline-start: 16px;
  font-size: 14.5px;
  line-height: 1.72;
  color: var(--ink-soft);
}

.page-about .about-line-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.68em;
  width: 6px;
  height: 1px;
  background: var(--grass-light);
}

/* ---------- 03 数据口径 ---------- */
.page-about .about-spec-list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: var(--rule);
}

.page-about .about-spec-row {
  display: grid;
  gap: 5px 28px;
  padding: 16px 12px;
  border-bottom: var(--rule);
  transition: background var(--t-fast);
}

.page-about .about-spec-row:hover {
  background: rgba(53, 166, 91, 0.09);
}

@media (min-width: 760px) {
  .page-about .about-spec-row {
    grid-template-columns: 178px minmax(0, 1fr);
    padding-inline: 14px;
  }
}

.page-about .about-spec-name {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: var(--grass-primary);
}

.page-about .about-spec-text {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.76;
  color: var(--ink-soft);
  max-width: 66ch;
}

.page-about .about-spec-foot {
  margin: 20px 0 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--neutral-moss);
  max-width: 62ch;
}

/* ---------- 04 团队与流程 ---------- */
.page-about .about-team {
  display: grid;
  gap: clamp(26px, 4vw, 52px);
}

@media (min-width: 940px) {
  .page-about .about-team {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
  }
}

.page-about .about-team-stats {
  margin: 0 0 20px;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--rule-line);
  border: var(--rule);
}

.page-about .about-team-stat {
  display: grid;
  gap: 4px;
  padding: 18px 16px;
  background: var(--card-ivory);
}

.page-about .about-team-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--about-tonenum);
  font-weight: 500;
  line-height: 1;
  color: var(--grass-primary);
}

.page-about .about-team-label {
  font-size: 13px;
  color: var(--ink-soft);
}

.page-about .about-team-total {
  margin: 0 0 clamp(24px, 3.4vw, 40px);
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-soft);
  max-width: 56ch;
}

.page-about .about-inline-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--ink-charcoal);
  font-weight: 500;
}

.page-about .about-flow-diagram {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px;
  background: var(--card-ivory);
  border: var(--rule);
}

@media (min-width: 760px) {
  .page-about .about-flow-diagram {
    flex-direction: row;
    align-items: center;
    gap: 14px;
  }
  .page-about .about-flow-step {
    flex: 1 1 0;
  }
  .page-about .about-flow-arrow {
    flex: 0 0 34px;
  }
}

.page-about .about-flow-step {
  min-width: 0;
}

.page-about .about-flow-index {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--grass-primary);
}

.page-about .about-flow-name {
  margin: 0 0 6px;
  font-size: 15.5px;
  font-weight: 700;
}

.page-about .about-flow-text {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--ink-soft);
}

.page-about .about-flow-arrow {
  display: flex;
  justify-content: center;
  color: var(--grass-light);
}

.page-about .about-flow-arrow svg {
  transform: rotate(90deg);
}

@media (min-width: 760px) {
  .page-about .about-flow-arrow svg {
    transform: none;
  }
}

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

.page-about .about-team-figure .media-frame {
  overflow: hidden;
  border: var(--rule);
  box-shadow: var(--shadow-1);
}

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

.page-about .about-team-figure .media-frame-caption {
  margin-block-start: 12px;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--neutral-moss);
}

/* ---------- 05 阶段演进 ---------- */
.page-about .about-timeline {
  background: var(--pitch-night);
  color: var(--paper-cream);
  padding: clamp(24px, 4vw, 46px) clamp(18px, 3.4vw, 44px) clamp(26px, 4vw, 44px);
  border-radius: var(--radius);
}

.page-about .about-timeline-banner {
  overflow: hidden;
  border-radius: var(--radius);
  margin-block-end: clamp(22px, 3.2vw, 34px);
}

.page-about .about-timeline-banner img {
  display: block;
  width: 100%;
  height: clamp(110px, 19vw, 220px);
  max-width: 100%;
  object-fit: cover;
}

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

.page-about .about-timeline .eyebrow {
  color: var(--volt-highlight);
}

.page-about .about-timeline .about-lines-lede {
  color: rgba(247, 243, 232, 0.74);
}

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

.page-about .about-stage-list::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 18px;
  bottom: 18px;
  border-left: 1px dashed rgba(201, 242, 77, 0.34);
}

.page-about .about-stage-list > li {
  position: relative;
  padding-block: 3px;
}

.page-about .about-stage-list > li::before {
  content: "";
  position: absolute;
  left: -29px;
  top: 24px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--volt-highlight);
  box-shadow: 0 0 0 3px rgba(201, 242, 77, 0.14);
}

.page-about .about-stage-summary {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 10px 12px;
  border-radius: var(--radius);
  cursor: pointer;
  list-style: none;
  transition: background var(--t-fast);
}

.page-about .about-stage-summary::-webkit-details-marker {
  display: none;
}

.page-about .about-stage-summary:hover {
  background: rgba(247, 243, 232, 0.06);
}

.page-about .about-stage-summary:focus-visible {
  outline: 2px solid var(--volt-highlight);
  outline-offset: 2px;
}

.page-about .about-stage-ver {
  flex: 0 0 auto;
  min-width: 46px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--volt-highlight);
}

.page-about .about-stage-name {
  font-size: clamp(1rem, 1.6vw, 1.12rem);
  font-weight: 500;
  color: var(--paper-cream);
}

.page-about .about-stage-toggle {
  position: relative;
  margin-inline-start: auto;
  flex: 0 0 auto;
  width: 14px;
  height: 14px;
  align-self: center;
}

.page-about .about-stage-toggle::before,
.page-about .about-stage-toggle::after {
  content: "";
  position: absolute;
  inset: 0;
  margin: auto;
  background: rgba(247, 243, 232, 0.68);
  transition: transform var(--t-fast), opacity var(--t-fast);
}

.page-about .about-stage-toggle::before {
  width: 12px;
  height: 1px;
}

.page-about .about-stage-toggle::after {
  width: 1px;
  height: 12px;
}

.page-about .about-stage[open] .about-stage-toggle::after {
  transform: scaleY(0);
  opacity: 0;
}

.page-about .about-stage-body {
  padding: 2px 12px 16px;
  max-width: 64ch;
}

.page-about .about-stage-body p {
  margin: 0 0 10px;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(247, 243, 232, 0.76);
}

.page-about .about-stage-body ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 6px;
}

.page-about .about-stage-body li {
  position: relative;
  padding-inline-start: 15px;
  font-size: 13.5px;
  line-height: 1.7;
  color: rgba(201, 242, 77, 0.86);
}

.page-about .about-stage-body li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 6px;
  height: 1px;
  background: rgba(201, 242, 77, 0.7);
}

/* ---------- 06 协作与肯定 ---------- */
.page-about .about-network {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
}

@media (min-width: 820px) {
  .page-about .about-network {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    align-items: start;
  }
}

.page-about .about-network-panel {
  padding: 22px 22px 20px;
  border: var(--rule);
  border-top: 2px solid var(--ink-charcoal);
  background: var(--card-ivory);
}

.page-about .about-network-panel--volt {
  border-top-color: var(--grass-primary);
}

.page-about .about-network-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 11px;
}

.page-about .about-network-list li {
  position: relative;
  padding-inline-start: 16px;
  font-size: 14.5px;
  line-height: 1.76;
  color: var(--ink-soft);
}

.page-about .about-network-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 7px;
  height: 1px;
  background: var(--grass-light);
}

.page-about .about-network-note {
  margin: 16px 0 0;
  padding-block-start: 14px;
  border-top: var(--rule);
  font-size: 12.5px;
  line-height: 1.72;
  color: var(--neutral-moss);
}

/* ---------- 07 服务边界 ---------- */
.page-about .about-boundary-list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 2px solid var(--ink-charcoal);
}

.page-about .about-boundary-item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 14px;
  padding: 16px 2px;
  border-bottom: var(--rule);
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--ink-soft);
}

.page-about .about-boundary-item a {
  color: var(--grass-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .about-boundary-item a:hover {
  color: var(--grass-light);
}

.page-about .about-boundary-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 12.5px;
  color: var(--grass-primary);
  padding-block-start: 3px;
}

.page-about .about-next {
  margin-block-start: clamp(28px, 4vw, 44px);
  padding: clamp(20px, 3vw, 30px);
  background: var(--paper-deep);
  border: var(--rule);
}

.page-about .about-next-text {
  margin: 0 0 18px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-soft);
  max-width: 58ch;
}

.page-about .about-next-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .about-closing {
  margin: clamp(32px, 5vw, 56px) 0 0;
  padding-block-start: 18px;
  border-top: var(--rule);
  font-size: 12.5px;
  line-height: 1.8;
  letter-spacing: 0.01em;
  color: var(--neutral-moss);
  max-width: 64ch;
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail-link,
  .page-about .about-spec-row,
  .page-about .about-stage-summary,
  .page-about .about-stage-toggle::before,
  .page-about .about-stage-toggle::after {
    transition: none;
  }
}