.page-about {
  --about-rail: 2.5rem;
  --about-gap: clamp(.75rem, 2vw, 1.5rem);
  display: block;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  padding-block: var(--space-s);
}

/* ---------- 首屏拼贴 ---------- */
.page-about .about-hero {
  display: grid;
  gap: var(--space-m);
  padding-block: var(--space-m) var(--space-m);
  border-bottom: var(--line);
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 7.4fr) minmax(0, 4.6fr);
    gap: var(--space-l);
    align-items: end;
  }
}

.page-about .about-hero__kicker {
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--signal-cyan);
  margin: 0;
}

.page-about .about-hero h1 {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -.02em;
  line-height: 1.06;
  font-size: clamp(1.85rem, 5.4vw, 3.35rem);
  color: var(--paper-white);
  margin: .7rem 0 1rem;
  text-wrap: balance;
}

.page-about .about-hero__lede {
  font-size: clamp(.98rem, 1.6vw, 1.08rem);
  line-height: 1.78;
  color: var(--paper-72);
  max-width: 60ch;
  margin: 0;
}

.page-about .about-hero__side {
  display: grid;
  align-content: end;
  border-top: 2px solid var(--brocade-red);
}

.page-about .side-block {
  display: grid;
  grid-template-columns: minmax(0, 6.5rem) minmax(0, 1fr);
  gap: .35rem 1rem;
  align-items: baseline;
  padding: .68rem 0;
  border-bottom: var(--line);
}

.page-about .side-block__key {
  margin: 0;
  font-size: .8rem;
  letter-spacing: .06em;
  color: var(--chalk-grey);
}

.page-about .side-block__val {
  margin: 0;
  font-size: .95rem;
  color: var(--paper-white);
}

/* ---------- 首屏三个关键数字 ---------- */
.page-about .hero-stats {
  display: grid;
  gap: var(--space-m);
  padding-block: var(--space-m);
  border-bottom: var(--line);
}

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

.page-about .hero-stats .stat__value {
  font-size: clamp(2.1rem, 5vw, 3rem);
  line-height: 1;
  letter-spacing: -.02em;
}

.page-about .hero-stats .stat__label {
  margin-top: .5rem;
  font-size: .88rem;
  color: var(--chalk-grey);
}

@media (min-width: 720px) {
  .page-about .hero-stats {
    grid-template-columns: 5fr 4fr 3fr;
    align-items: end;
  }
  .page-about .hero-stats__b,
  .page-about .hero-stats__c {
    padding-left: var(--space-m);
    border-left: var(--line);
  }
  .page-about .hero-stats__b .stat__value {
    font-size: clamp(1.8rem, 3.6vw, 2.3rem);
  }
  .page-about .hero-stats__c .stat__value {
    font-size: clamp(1.5rem, 2.8vw, 1.85rem);
  }
}

/* ---------- 区块通用 ---------- */
.page-about .about-block {
  padding-block: var(--space-l) 0;
}

.page-about .about-block .section-head {
  margin-bottom: var(--space-m);
}

.page-about .about-slant {
  height: 0;
  margin-block: var(--space-l) var(--space-m);
  border-top: 1px solid var(--grid-line);
  transform: rotate(-1.2deg);
  transform-origin: left center;
}

.page-about .about-slant--cyan {
  border-top: 2px solid rgba(70, 227, 196, .55);
  transform: rotate(1deg);
}

.page-about .about-breath {
  height: clamp(3rem, 9vw, 7rem);
}

/* ---------- 品牌自述 ---------- */
.page-about .about-split {
  align-items: start;
  row-gap: var(--space-m);
}

.page-about .about-split__text p {
  margin-top: 0;
}

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

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

.page-about .about-figure__cap {
  margin: .6rem 0 0;
  font-size: .8rem;
  line-height: 1.6;
  color: var(--chalk-grey);
  border-left: 2px solid var(--brocade-red);
  padding-left: .7rem;
}

.page-about .about-figure__cap--top {
  margin: 0 0 var(--space-s);
  max-width: 62ch;
}

.page-about .about-figure--wide,
.page-about .about-figure--full {
  margin-top: var(--space-m);
}

/* ---------- 时间轴 ---------- */
.page-about .about-timeline-wrap {
  row-gap: var(--space-m);
}

.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  min-width: 0;
}

.page-about .timeline__row {
  display: grid;
  grid-template-columns: var(--about-rail) minmax(0, 1fr);
  gap: var(--about-gap);
  padding-bottom: var(--space-m);
}

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

.page-about .timeline__rail {
  position: relative;
  display: flex;
  justify-content: center;
}

.page-about .timeline__row:not(:last-child) .timeline__rail::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 1.9rem;
  bottom: calc(-1 * var(--space-m));
  width: 2px;
  transform: translateX(-50%);
  background: linear-gradient(180deg, var(--signal-cyan), rgba(70, 227, 196, .12));
}

.page-about .timeline__node {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 1.5rem;
  background: var(--brocade-red);
  color: var(--paper-white);
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .02em;
  border-radius: 1px;
  position: relative;
  z-index: 1;
}

.page-about .timeline__card {
  position: relative;
  padding: var(--space-m);
}

.page-about .timeline__stage {
  margin: 0 0 .5rem;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .08em;
  color: var(--signal-cyan);
}

.page-about .timeline__title {
  font-family: var(--font-display);
  font-size: clamp(1.15rem, 2.4vw, 1.45rem);
  font-weight: 700;
  letter-spacing: -.01em;
  line-height: 1.25;
  color: var(--paper-white);
  margin: 0 0 .6rem;
}

.page-about .timeline__text {
  margin: 0;
  font-size: .95rem;
  line-height: 1.8;
  color: var(--paper-72);
}

/* 版本索引 */
.page-about .about-rail {
  min-width: 0;
}

.page-about .ver-index {
  border-top: 2px solid var(--signal-cyan);
  padding-top: .9rem;
}

@media (min-width: 900px) {
  .page-about .ver-index {
    position: sticky;
    top: 6rem;
  }
}

.page-about .ver-index__title {
  margin: 0 0 .8rem;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--chalk-grey);
}

.page-about .ver-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: .1rem;
}

.page-about .ver-index__list a {
  display: block;
  padding: .5rem .1rem;
  font-size: .88rem;
  line-height: 1.5;
  color: var(--paper-72);
  text-decoration: none;
  border-bottom: var(--line);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

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

.page-about .ver-index__list a[aria-current="true"] {
  color: var(--signal-cyan);
  border-color: var(--signal-cyan);
}

/* ---------- 团队树 ---------- */
.page-about .tree {
  display: grid;
  gap: 0;
}

.page-about .tree__root {
  border: var(--line);
  border-left: 3px solid var(--brocade-red);
  background: var(--pitch-deep);
  padding: .9rem 1.1rem;
}

.page-about .tree__root-kicker {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--chalk-grey);
}

.page-about .tree__root-title {
  margin: .3rem 0 0;
  font-family: var(--font-display);
  font-size: clamp(1rem, 2.2vw, 1.25rem);
  font-weight: 700;
  color: var(--paper-white);
}

.page-about .tree__wires {
  display: none;
  width: 100%;
  height: 2.2rem;
  fill: none;
  stroke: rgba(70, 227, 196, .5);
  stroke-width: .5;
  vector-effect: non-scaling-stroke;
}

.page-about .tree__branches {
  display: grid;
  gap: var(--space-s);
}

@media (min-width: 820px) {
  .page-about .tree__wires {
    display: block;
  }
  .page-about .tree__branches {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: var(--space-m);
  }
}

.page-about .tree__branch {
  border: var(--line);
  border-top: 2px solid var(--grid-line);
  background: linear-gradient(180deg, rgba(16, 35, 28, .9), rgba(11, 14, 13, .6));
  padding: 1rem 1rem 1.2rem;
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.page-about .tree__branch:hover,
.page-about .tree__branch:focus-within {
  border-top-color: var(--signal-cyan);
  transform: translateY(-2px);
}

.page-about .tree__branch:nth-child(2):hover {
  border-top-color: var(--alert-orange);
}

.page-about .tree__count {
  margin: .6rem 0 .4rem;
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--paper-white);
}

.page-about .tree__title {
  margin: 0 0 .5rem;
  font-size: 1rem;
  font-weight: 600;
  color: var(--paper-white);
}

.page-about .tree__text {
  margin: 0;
  font-size: .88rem;
  line-height: 1.75;
  color: var(--paper-72);
}

.page-about .tree__volunteer {
  margin-top: var(--space-m);
  padding: 1rem 1.1rem;
  background: var(--jewel-indigo);
  border-left: 3px solid var(--alert-orange);
}

.page-about .tree__volunteer-count {
  margin: 0 0 .4rem;
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--alert-orange);
}

.page-about .tree__volunteer-text {
  margin: 0;
  font-size: .9rem;
  line-height: 1.78;
  color: var(--paper-88);
  max-width: 72ch;
}

/* ---------- 五步流程 ---------- */
.page-about .steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--space-s);
}

@media (min-width: 640px) {
  .page-about .steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1000px) {
  .page-about .steps {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: var(--about-gap);
  }
}

.page-about .steps__item {
  border-top: 2px solid var(--signal-cyan);
  padding-top: .8rem;
}

.page-about .steps__item:nth-child(2n) {
  border-top-color: var(--alert-orange);
}

.page-about .steps__num {
  display: block;
  font-family: var(--font-mono);
  font-size: .78rem;
  letter-spacing: .1em;
  color: var(--brocade-red-lite);
}

.page-about .steps__title {
  margin: .35rem 0 .45rem;
  font-family: var(--font-display);
  font-size: 1.02rem;
  font-weight: 700;
  letter-spacing: 0;
  color: var(--paper-white);
}

.page-about .steps__text {
  margin: 0;
  font-size: .85rem;
  line-height: 1.72;
  color: var(--paper-72);
}

/* ---------- 方法与口径小卡 ---------- */
.page-about .about-method-grid {
  margin-top: var(--space-l);
  row-gap: var(--space-m);
}

.page-about .about-method-grid .prose p {
  margin-top: 0;
}

.page-about .about-note-col {
  display: grid;
  gap: var(--space-s);
  align-content: start;
  min-width: 0;
}

.page-about .note-card {
  position: relative;
  padding: var(--space-m);
}

.page-about .note-card__key {
  margin: 0 0 .45rem;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--signal-cyan);
}

.page-about .note-card__val {
  margin: 0 0 .5rem;
  font-size: .95rem;
  line-height: 1.7;
  color: var(--paper-white);
}

.page-about .note-card__foot {
  margin: 0;
  font-size: .8rem;
  line-height: 1.6;
  color: var(--chalk-grey);
}

/* ---------- 更新节奏表 ---------- */
.page-about .table-wrap {
  width: 100%;
  overflow-x: auto;
  border: var(--line);
  background: rgba(16, 35, 28, .45);
}

.page-about .about-table__caption {
  text-align: left;
  padding: .8rem 1rem .2rem;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--chalk-grey);
}

.page-about .about-table {
  width: 100%;
  min-width: 560px;
  border-collapse: collapse;
}

.page-about .about-table th,
.page-about .about-table td {
  padding: .85rem 1rem;
  text-align: left;
  vertical-align: top;
  font-size: .88rem;
  line-height: 1.65;
  border-bottom: var(--line);
}

.page-about .about-table thead th {
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--chalk-grey);
}

.page-about .about-table tbody td:first-child {
  color: var(--signal-cyan);
  white-space: nowrap;
}

.page-about .about-table tbody tr {
  transition: background-color var(--dur) var(--ease);
}

.page-about .about-table tbody tr:hover {
  background: rgba(70, 227, 196, .06);
}

/* ---------- 对外协作 ---------- */
.page-about .collab {
  display: grid;
  gap: var(--space-m);
}

@media (min-width: 860px) {
  .page-about .collab {
    grid-template-columns: minmax(0, 5fr) minmax(0, 3.5fr) minmax(0, 3.5fr);
  }
}

.page-about .collab__item {
  border-left: var(--line);
  padding-left: var(--space-s);
}

.page-about .collab__item:first-child {
  border-left: 3px solid var(--brocade-red);
}

.page-about .collab__num {
  margin: 0 0 .4rem;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .12em;
  color: var(--chalk-grey);
}

.page-about .collab__title {
  margin: 0 0 .5rem;
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--paper-white);
}

.page-about .collab__text {
  margin: 0;
  font-size: .9rem;
  line-height: 1.78;
  color: var(--paper-72);
}

/* ---------- 纠错与反馈 ---------- */
.page-about .fix-grid {
  row-gap: var(--space-m);
}

.page-about .fix-grid__title {
  font-family: var(--font-display);
  font-size: clamp(1.3rem, 3vw, 1.85rem);
  font-weight: 700;
  letter-spacing: -.02em;
  color: var(--paper-white);
  margin: 0 0 .8rem;
}

.page-about .fix-grid__text {
  margin: 0 0 var(--space-s);
  font-size: .95rem;
  line-height: 1.8;
  color: var(--paper-72);
}

.page-about .fix-steps {
  margin: 0;
  padding-left: 1.2rem;
  display: grid;
  gap: .4rem;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--paper-88);
}

.page-about .fix-card {
  position: relative;
  padding: var(--space-m);
  display: grid;
  gap: .4rem;
}

.page-about .fix-card__key {
  margin: 0;
  font-family: var(--font-mono);
  font-size: .74rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--chalk-grey);
}

.page-about .fix-card__val {
  margin: 0;
  font-size: 1rem;
  color: var(--signal-cyan);
  word-break: break-all;
}

.page-about .fix-card__foot {
  margin: .3rem 0 .8rem;
  font-size: .82rem;
  line-height: 1.7;
  color: var(--paper-72);
}

.page-about .fix-card .btn {
  justify-self: start;
}

/* ---------- 延伸入口 ---------- */
.page-about .next-links {
  margin-top: var(--space-l);
  padding-bottom: var(--space-l);
}

@media (max-width: 719px) {
  .page-about .timeline__row {
    grid-template-columns: 1.9rem minmax(0, 1fr);
    gap: .7rem;
  }

  .page-about .timeline__node {
    width: 1.9rem;
    height: 1.3rem;
    font-size: .62rem;
  }

  .page-about .hero-stats .stat__value {
    font-size: 2rem;
  }
}