.page-about {
  --about-cut: 18px;
}

/* ---------- 封面层 ---------- */
.page-about .about-cover {
  position: relative;
  padding: clamp(40px, 6vw, 92px) 0 clamp(36px, 5vw, 68px);
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(1100px 460px at 10% -12%, rgba(56, 232, 212, 0.12), transparent 62%),
    radial-gradient(760px 380px at 96% 8%, rgba(255, 90, 43, 0.09), transparent 60%),
    linear-gradient(180deg, var(--ink-900), var(--ink-950));
  overflow: hidden;
}

.page-about .about-cover::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    repeating-linear-gradient(90deg, rgba(43, 58, 85, 0.42) 0 1px, transparent 1px 96px),
    repeating-linear-gradient(0deg, rgba(43, 58, 85, 0.28) 0 1px, transparent 1px 96px);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.7), transparent 88%);
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.7), transparent 88%);
  pointer-events: none;
}

.page-about .about-cover__inner {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 5vw, 48px);
}

.page-about .about-cover__title {
  margin: 14px 0 18px;
  font-size: clamp(30px, 7.2vw, 52px);
  line-height: 1.15;
  font-weight: 900;
  letter-spacing: 0.04em;
  color: var(--text);
}

.page-about .about-cover__text {
  max-width: 60ch;
  margin: 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-cover__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-figures {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, calc(100% - 22px) 0, 100% 22px, 100% 100%, 0 100%);
}

.page-about .about-figures li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  padding: 15px 18px;
  background: var(--ink-900);
}

.page-about .about-figures__num {
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.page-about .about-figures li:nth-child(2) .about-figures__num,
.page-about .about-figures li:nth-child(4) .about-figures__num {
  color: var(--orange);
}

.page-about .about-figures__label {
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
  text-align: right;
}

/* ---------- 长卷主体 ---------- */
.page-about .about-body {
  padding-top: clamp(32px, 5vw, 56px);
  padding-bottom: clamp(48px, 7vw, 96px);
  row-gap: 32px;
}

.page-about .about-rail__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .about-toc {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 8px;
  scrollbar-width: thin;
}

.page-about .about-toc .toc__link {
  flex: 0 0 auto;
  white-space: nowrap;
  padding: 8px 12px;
  border: 1px solid var(--line);
  font-size: 14px;
  color: var(--muted);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-toc .toc__link:hover {
  color: var(--text);
  border-color: var(--cyan-deep);
}

.page-about .about-toc .toc__link.is-active {
  color: var(--ink-950);
  background: var(--cyan);
  border-color: var(--cyan);
  font-weight: 700;
}

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

.page-about .about-sec {
  padding: clamp(28px, 4vw, 44px) 0;
}

.page-about .about-sec + .about-sec {
  border-top: 1px solid var(--line);
  margin-top: clamp(24px, 4vw, 48px);
  padding-top: clamp(36px, 5vw, 64px);
}

.page-about .about-sec__head {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.page-about .about-sec__head .chapter-no {
  flex: 0 0 auto;
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--cyan);
  padding-top: 6px;
}

.page-about .about-sec__head h2 {
  margin: 6px 0 0;
  font-size: clamp(22px, 3.6vw, 32px);
  line-height: 1.32;
  font-weight: 900;
  letter-spacing: 0.05em;
  color: var(--text);
}

.page-about .about-sec .band {
  display: block;
  width: 96px;
  height: 3px;
  margin: 20px 0 0;
  background: linear-gradient(90deg, var(--cyan), var(--orange));
}

.page-about .about-lead {
  max-width: 68ch;
  margin: 22px 0 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  margin-top: 22px;
}

.page-about .about-split .prose p {
  margin: 0 0 16px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--text);
}

.page-about .about-split .prose p:last-child {
  margin-bottom: 0;
}

/* 关键数字切角面板 */
.page-about .about-key {
  align-self: start;
  padding: 20px 22px;
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan);
  clip-path: polygon(0 0, calc(100% - var(--about-cut)) 0, 100% var(--about-cut), 100% 100%, 0 100%);
}

.page-about .about-key__label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}

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

.page-about .about-key__list li {
  display: flex;
  gap: 10px;
  padding: 9px 0;
  border-top: 1px solid var(--line);
  font-size: 14px;
  line-height: 1.7;
  color: var(--text);
}

.page-about .about-key__list li:first-child {
  border-top: 0;
}

.page-about .about-key__list .mono {
  flex: 0 0 auto;
  color: var(--cyan);
  font-size: 12px;
  letter-spacing: 0.1em;
  padding-top: 3px;
}

/* 橘红竖线说明块 */
.page-about .about-note {
  align-self: start;
  padding: 18px 20px;
  background: var(--ink-900);
  border-left: 3px solid var(--orange);
}

.page-about .about-note p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

/* 规模统计 */
.page-about .about-scale {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin-top: 24px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-scale .stat {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 18px 20px;
  background: var(--ink-900);
}

.page-about .about-scale .stat__num {
  font-size: clamp(26px, 4.4vw, 34px);
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--cyan);
  line-height: 1.1;
}

.page-about .about-scale .stat__num--orange {
  color: var(--orange);
}

.page-about .about-scale .stat__label {
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .about-note-line {
  margin: 22px 0 0;
  padding-left: 16px;
  border-left: 2px solid var(--line);
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

/* 团队分工 */
.page-about .about-team {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin-top: 24px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-team__item {
  padding: 20px;
  background: var(--ink-900);
  transition: background var(--dur) var(--ease);
}

.page-about .about-team__item:hover {
  background: var(--ink-800);
}

.page-about .about-team__no {
  display: block;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .about-team__item h3 {
  margin: 10px 0 8px;
  font-size: 18px;
  letter-spacing: 0.04em;
  color: var(--text);
}

.page-about .about-team__item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

/* 发展历程时间轴 */
.page-about .about-timeline {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  position: relative;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 17px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--cyan), var(--orange));
  opacity: 0.5;
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 20px 56px;
}

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

.page-about .about-timeline__no {
  position: absolute;
  left: 0;
  top: 2px;
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--ink-950);
  background: var(--cyan);
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 10px, 100% 100%, 0 100%);
}

.page-about .about-timeline__item:nth-child(5) .about-timeline__no {
  background: var(--orange);
}

.page-about .about-timeline__card {
  padding: 16px 18px;
  background: var(--ink-900);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, calc(100% - var(--about-cut)) 0, 100% var(--about-cut), 100% 100%, 0 100%);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-timeline__item:hover .about-timeline__card,
.page-about .about-timeline__item:focus-within .about-timeline__card {
  transform: translateX(4px);
  border-color: var(--cyan-deep);
  background: var(--ink-800);
}

.page-about .about-timeline__card h3 {
  margin: 0 0 8px;
  font-size: 17px;
  letter-spacing: 0.04em;
  color: var(--text);
}

.page-about .about-timeline__card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

/* 奶油纸白区块 */
.page-about .about-paper {
  align-self: start;
  padding: clamp(20px, 3vw, 28px);
  background: var(--paper);
  border: 1px solid var(--paper-line);
  color: var(--paper-ink);
  clip-path: polygon(0 0, calc(100% - 20px) 0, 100% 20px, 100% 100%, 0 100%);
}

.page-about .about-paper h3 {
  margin: 0 0 12px;
  font-size: 17px;
  letter-spacing: 0.04em;
  color: var(--paper-ink);
}

.page-about .about-paper ul {
  margin: 0;
  padding-left: 18px;
}

.page-about .about-paper li {
  margin-bottom: 8px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--paper-soft);
}

.page-about .about-paper li:last-child {
  margin-bottom: 0;
}

/* 图片 */
.page-about .about-figure {
  margin: 26px 0 0;
}

.page-about .about-figure .media__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
}

.page-about .about-figure .media__caption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

/* 联系方式行 */
.page-about .about-contact {
  margin-top: 24px;
  border: 1px solid var(--line);
  background: var(--ink-900);
}

.page-about .about-contact__row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 14px;
  padding: 14px 18px;
}

.page-about .about-contact__row + .about-contact__row {
  border-top: 1px solid var(--line);
}

.page-about .about-contact__key {
  flex: 0 0 auto;
  min-width: 62px;
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--muted);
}

.page-about .about-contact__val {
  flex: 1 1 200px;
  min-width: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--text);
  word-break: break-word;
}

/* 结尾入口 */
.page-about .about-cta {
  margin-top: clamp(32px, 5vw, 64px);
  padding: clamp(24px, 4vw, 40px);
  background: linear-gradient(125deg, var(--ink-800), var(--ink-900) 70%);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, calc(100% - 26px) 0, 100% 26px, 100% 100%, 0 100%);
}

.page-about .about-cta h2 {
  margin: 8px 0 10px;
  font-size: clamp(20px, 3.2vw, 28px);
  letter-spacing: 0.05em;
  color: var(--text);
}

.page-about .about-cta p {
  max-width: 62ch;
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
}

/* 折叠面板微调 */
.page-about .about-split .fold {
  margin-top: 20px;
}

.page-about .about-split .fold__head {
  font-size: 15px;
  letter-spacing: 0.03em;
}

.page-about .about-split .fold__body ul {
  margin: 0;
  padding-left: 18px;
}

.page-about .about-split .fold__body li {
  margin-bottom: 6px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

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

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

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

@media (min-width: 960px) {
  .page-about .about-cover__inner {
    grid-template-columns: minmax(0, 1.62fr) minmax(0, 0.88fr);
    align-items: end;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--head-h) + 24px);
    align-self: start;
  }

  .page-about .about-toc {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-bottom: 0;
    border-left: 1px solid var(--line);
  }

  .page-about .about-toc .toc__link {
    white-space: normal;
    border: 0;
    border-left: 2px solid transparent;
    padding: 10px 12px;
    font-size: 14px;
  }

  .page-about .about-toc .toc__link.is-active {
    background: transparent;
    color: var(--cyan);
    border-left-color: var(--cyan);
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 0.92fr);
    gap: 36px;
  }

  .page-about .about-scale {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

@media (min-width: 1200px) {
  .page-about .about-team {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-cta {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 36px;
  }

  .page-about .about-cta__links {
    margin-top: 0;
    flex: 0 0 auto;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-timeline__card,
  .page-about .about-team__item,
  .page-about .about-toc .toc__link {
    transition: none;
  }

  .page-about .about-timeline__item:hover .about-timeline__card {
    transform: none;
  }
}