.page-about {
  --about-rail: 280px;
  --about-flow-gap: clamp(56px, 8vw, 104px);
  background: var(--snow);
  color: var(--text);
  font-family: var(--font-sans);
  overflow-x: clip;
}

.page-about .breadcrumb {
  padding-top: clamp(16px, 3vw, 28px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  border-bottom: 1px solid var(--line);
  padding: clamp(28px, 4vw, 56px) 0 clamp(48px, 7vw, 96px);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(32px, 5vw, 56px);
  align-items: center;
}

.page-about .about-hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--sand);
}

.page-about .about-hero__eyebrow::before {
  content: "";
  width: 26px;
  height: 2px;
  border-radius: var(--r-pill);
  background: var(--copper);
}

.page-about .about-hero__title {
  margin: 0 0 22px;
  font-size: clamp(38px, 6.2vw, 72px);
  font-weight: 900;
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--text);
}

.page-about .about-hero__sub {
  margin: 0 0 16px;
  max-width: 34em;
  font-size: clamp(17px, 1.8vw, 20px);
  line-height: 1.7;
  color: var(--text);
}

.page-about .about-hero__body {
  margin: 0 0 30px;
  max-width: 34em;
  font-size: 17px;
  line-height: 1.75;
  color: var(--sand);
}

.page-about .about-hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 24px;
  padding-top: 26px;
  border-top: 1px solid var(--line);
}

.page-about .about-hero__stats .stat__value {
  display: block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(26px, 3vw, 34px);
  line-height: 1.1;
  letter-spacing: 0.04em;
  color: var(--copper);
}

.page-about .about-hero__stats .stat__label {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--sand);
}

.page-about .about-hero__visual {
  display: flex;
  flex-direction: column;
  gap: 18px;
  padding: clamp(18px, 3vw, 30px);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: radial-gradient(circle at 62% 36%, var(--ink-soft) 0%, var(--ink) 68%);
}

.page-about .about-hero__svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-hero__legend {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  font-size: 12px;
  color: #9FB3BC;
}

/* ---------- 主体两栏 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(36px, 5vw, 56px);
  padding-top: clamp(44px, 6vw, 96px);
  padding-bottom: clamp(56px, 8vw, 120px);
}

.page-about .about-index {
  align-self: start;
  padding: 20px 18px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--snow-mid);
}

.page-about .about-index .index-rail__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--sand);
}

.page-about .about-index .index-rail__list {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .index-link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 12px;
  border-radius: var(--r-pill);
  font-size: 14px;
  line-height: 1.4;
  color: var(--text);
  text-decoration: none;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .index-link__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--copper);
  transition: color var(--dur) var(--ease);
}

.page-about .index-link:is(:hover, :focus-visible) {
  background: var(--copper);
  color: #fff;
}

.page-about .index-link:is(:hover, :focus-visible) .index-link__num {
  color: #fff;
}

/* ---------- 章节节奏 ---------- */
.page-about .about-section {
  scroll-margin-top: calc(var(--bar-h-compact) + 32px);
}

.page-about .about-flow > .about-section + .about-section {
  margin-top: var(--about-flow-gap);
  padding-top: var(--about-flow-gap);
  border-top: 1px solid var(--line);
}

/* ---------- 01 时间轴 ---------- */
.page-about .about-timeline {
  position: relative;
  margin-top: clamp(26px, 4vw, 44px);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--snow-mid);
  overflow: hidden;
}

.page-about .about-timeline__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.13;
  filter: grayscale(1) contrast(1.15);
  pointer-events: none;
}

.page-about .about-timeline__inner {
  position: relative;
  padding: clamp(24px, 3.5vw, 44px) clamp(18px, 3vw, 36px);
}

.page-about .about-timeline__track {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(232px, 1fr);
  gap: clamp(20px, 3vw, 34px);
  padding-bottom: 14px;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
}

.page-about .tl-node {
  position: relative;
  min-width: 0;
  padding-top: 32px;
  scroll-snap-align: start;
}

.page-about .tl-node::after {
  content: "";
  position: absolute;
  top: 8px;
  left: 17px;
  right: -24px;
  height: 1px;
  background: var(--line);
}

.page-about .tl-node:last-child::after {
  right: auto;
  width: 38%;
}

.page-about .tl-node__dot {
  position: absolute;
  top: 2px;
  left: 0;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--copper);
  box-shadow: 0 0 0 5px var(--snow-mid);
  transition: background var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .tl-node__year {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(26px, 2.6vw, 34px);
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--copper-deep);
}

.page-about .tl-node__title {
  margin: 0 0 10px;
  font-size: 18px;
  font-weight: 800;
  line-height: 1.4;
  color: var(--text);
}

.page-about .tl-node__body {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.72;
  color: var(--sand);
}

.page-about .tl-node__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
  max-height: 220px;
  opacity: 1;
  overflow: hidden;
  transition: max-height var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

/* ---------- 02 记录方法 ---------- */
.page-about .method-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(26px, 4vw, 44px);
  margin-top: clamp(26px, 4vw, 40px);
  align-items: start;
}

.page-about .method-steps {
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: method-step;
}

.page-about .method-step {
  position: relative;
  margin: 0;
  padding: 20px 22px 20px 76px;
  border: 1px solid transparent;
  border-radius: var(--r-md);
  background: var(--snow-mid);
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .method-step::before {
  counter-increment: method-step;
  content: counter(method-step, decimal-leading-zero);
  position: absolute;
  top: 20px;
  left: 22px;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 20px;
  letter-spacing: 0.06em;
  color: var(--copper);
}

.page-about .method-step:is(:hover, :focus-within) {
  border-color: var(--copper);
  background: #fff;
}

.page-about .method-step__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 800;
  line-height: 1.4;
  color: var(--text);
}

.page-about .method-step__body {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--sand);
}

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

/* ---------- 03 字段定义表 ---------- */
.page-about .field-table-wrap {
  margin-top: clamp(26px, 4vw, 40px);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: #fff;
  overflow: hidden;
}

.page-about .field-table-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .field-table {
  width: 100%;
  min-width: 680px;
  border-collapse: collapse;
  font-size: 15px;
}

.page-about .field-table__caption {
  padding: 16px 20px 0;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--sand);
}

.page-about .field-table th,
.page-about .field-table td {
  padding: 15px 20px;
  text-align: left;
  vertical-align: top;
  line-height: 1.7;
}

.page-about .field-table thead th {
  background: var(--ink);
  color: #fff;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  white-space: nowrap;
}

.page-about .field-table thead th:first-child {
  color: var(--pulse);
}

.page-about .field-table tbody tr {
  border-top: 1px solid var(--line);
  transition: background var(--dur) var(--ease);
}

.page-about .field-table tbody tr:nth-child(odd) {
  background: var(--snow);
}

.page-about .field-table tbody tr:nth-child(even) {
  background: var(--snow-mid);
}

.page-about .field-table tbody tr:hover {
  background: rgba(176, 82, 43, 0.16);
}

.page-about .field-table__name {
  font-weight: 800;
  white-space: nowrap;
  color: var(--copper-deep);
}

/* ---------- 04 版本演进 ---------- */
.page-about .version-rail {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: clamp(26px, 4vw, 40px);
}

.page-about .version-pill {
  display: inline-flex;
  flex-direction: column;
  gap: 3px;
  padding: 11px 20px;
  border: 1px solid var(--line);
  border-radius: var(--r-pill);
  background: #fff;
  color: var(--text);
  text-decoration: none;
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .version-pill__id {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.page-about .version-pill__hint {
  font-size: 12px;
  color: var(--sand);
  transition: color var(--dur) var(--ease);
}

.page-about .version-pill:is(:hover, :focus-visible) {
  border-color: var(--copper);
  background: var(--copper);
  color: #fff;
}

.page-about .version-pill:is(:hover, :focus-visible) .version-pill__hint {
  color: rgba(255, 255, 255, 0.88);
}

.page-about .version-cards {
  display: grid;
  gap: 14px;
  margin-top: 22px;
}

.page-about .version-card {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  padding: 22px 24px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: #fff;
  scroll-margin-top: calc(var(--bar-h-compact) + 32px);
  transition: border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.page-about .version-card:target {
  border-color: var(--copper);
  box-shadow: 0 0 0 3px rgba(176, 82, 43, 0.16);
}

.page-about .version-card__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .version-card__id {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--copper);
}

.page-about .version-card__year {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--sand);
}

.page-about .version-card__body {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--text);
}

/* ---------- 05 团队与轮值 ---------- */
.page-about .team-media {
  margin: clamp(26px, 4vw, 40px) 0 0;
}

.page-about .team-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin-top: 22px;
}

.page-about .team-card {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--snow-mid);
}

.page-about .team-card__name {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 800;
  line-height: 1.4;
  color: var(--text);
}

.page-about .team-card__body {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--sand);
}

.page-about .team-note {
  margin: 22px 0 0;
  padding: 20px 24px;
  border-radius: var(--r-md);
  background: var(--ink);
  color: #D7E2E7;
  font-size: 15px;
  line-height: 1.75;
}

.page-about .team-note strong {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--pulse);
}

/* ---------- 06 节奏与纠错 ---------- */
.page-about .cadence-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin-top: clamp(26px, 4vw, 40px);
}

.page-about .cadence-card {
  padding: 20px 22px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: #fff;
}

.page-about .cadence-card__key {
  display: inline-block;
  margin-bottom: 10px;
  padding: 6px 14px;
  border-radius: var(--r-pill);
  background: var(--ink);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--pulse);
}

.page-about .cadence-card__body {
  margin: 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--sand);
}

.page-about .faq-folds {
  display: grid;
  gap: 12px;
  margin-top: clamp(26px, 4vw, 40px);
}

.page-about .fold {
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--snow-mid);
  overflow: hidden;
}

.page-about .fold-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  padding: 18px 22px;
  border: 0;
  background: transparent;
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 700;
  line-height: 1.5;
  text-align: left;
  color: var(--text);
  cursor: pointer;
}

.page-about .fold-head__arrow {
  flex: 0 0 auto;
  font-size: 20px;
  line-height: 1;
  color: var(--copper);
  transition: transform var(--dur) var(--ease);
}

.page-about .fold-panel__inner {
  padding: 0 22px 20px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--sand);
}

.page-about .fold-panel__inner p {
  margin: 0;
}

.page-about .fold-panel__inner a {
  color: var(--copper-deep);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 结尾索引 ---------- */
.page-about .about-next__title {
  margin: 0 0 18px;
  font-size: clamp(22px, 2.6vw, 30px);
  font-weight: 900;
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .about-next__list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-next__link {
  display: block;
  padding: 16px 20px;
  border: 1px solid var(--line);
  border-radius: var(--r-pill);
  background: var(--snow-mid);
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  text-decoration: none;
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-next__link:is(:hover, :focus-visible) {
  border-color: var(--copper);
  background: var(--copper);
  color: #fff;
}

/* ---------- 断点 ---------- */
@media (min-width: 560px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 720px) {
  .page-about .team-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .cadence-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-next__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .version-card {
    grid-template-columns: 176px minmax(0, 1fr);
    align-items: baseline;
    gap: 8px 24px;
  }
}

@media (min-width: 960px) {
  .page-about .about-hero__grid {
    grid-template-columns: 5fr 6fr;
    gap: clamp(40px, 5vw, 72px);
  }
}

@media (min-width: 1000px) {
  .page-about .method-grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
  }
}

@media (min-width: 1020px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(40px, 6vw, 88px);
  }

  .page-about .about-index {
    position: sticky;
    top: calc(var(--bar-h-compact) + 28px);
  }
}

/* 桌面指针设备：时间轴胶囊随悬停展开 */
@media (hover: hover) and (pointer: fine) and (min-width: 900px) {
  .page-about .tl-node__tags {
    max-height: 0;
    opacity: 0;
  }

  .page-about .tl-node:is(:hover, :focus-within) .tl-node__tags {
    max-height: 220px;
    opacity: 1;
  }

  .page-about .tl-node:is(:hover, :focus-within) .tl-node__dot {
    background: var(--signal);
    box-shadow: 0 0 0 5px rgba(255, 122, 24, 0.18);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .tl-node__tags,
  .page-about .tl-node__dot,
  .page-about .fold-head__arrow,
  .page-about .index-link,
  .page-about .version-pill,
  .page-about .about-next__link {
    transition: none;
  }
}