.page-about {
  --about-rail-w: 190px;
  --about-gap: 1px;
}

.page-about .about-top {
  padding-top: clamp(18px, 3vw, 30px);
}

/* 首屏 */
.page-about .about-hero__inner {
  display: grid;
  gap: clamp(26px, 4vw, 44px);
  padding: clamp(24px, 4vw, 44px) 0 clamp(36px, 5vw, 60px);
}

.page-about .about-hero__title,
.page-about .about-hero__copy h1 {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(32px, 8vw, 66px);
  line-height: 1.06;
  letter-spacing: 0.02em;
  margin: 14px 0 20px;
  color: var(--chalk);
}

.page-about .about-hero__lead {
  max-width: 48ch;
  margin: 0;
  font-size: clamp(15px, 2.6vw, 17px);
  line-height: 1.9;
  color: var(--concrete);
}

.page-about .about-hero__meta {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--about-gap);
  background: var(--line);
  border: 1px solid var(--line);
  margin-top: clamp(24px, 4vw, 34px);
}

.page-about .about-meta {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 16px;
  background: var(--ink);
}

.page-about .about-meta__label {
  font-size: 12px;
  line-height: 1.5;
  color: var(--mist);
  letter-spacing: 0.02em;
}

.page-about .about-hero__visual {
  margin: 0;
  border: 1px solid var(--line-mid);
  background: var(--ink-deep);
}

.page-about .about-hero__visual .media {
  border: 0;
}

.page-about .about-hero__visual img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.85) contrast(1.05);
}

.page-about .about-hero__caption {
  padding: 12px 14px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

/* 左侧台阶索引 + 正文 */
.page-about .about-body {
  display: grid;
  gap: 0;
  padding-bottom: clamp(48px, 7vw, 84px);
}

.page-about .about-rail {
  display: none;
}

.page-about .about-rail__note {
  margin: 0 0 18px;
  writing-mode: vertical-rl;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.3em;
  color: var(--mist);
  border-left: 1px solid var(--line-mid);
  padding-left: 8px;
  height: 132px;
}

/* 章节 */
.page-about .about-sec {
  padding: clamp(34px, 5vw, 56px) 0;
  border-top: 1px solid var(--line);
}

.page-about .about-sec:first-child {
  border-top: 0;
  padding-top: clamp(10px, 2vw, 18px);
}

.page-about .about-sec__head {
  display: flex;
  align-items: flex-start;
  gap: clamp(12px, 2.4vw, 22px);
  margin-bottom: clamp(20px, 3vw, 30px);
}

.page-about .about-sec__num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: clamp(38px, 9vw, 62px);
  line-height: 0.85;
  letter-spacing: -0.02em;
  color: transparent;
  -webkit-text-stroke: 1px var(--line-strong);
  padding-top: 2px;
}

.page-about .about-sec__title {
  margin: 6px 0 0;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(21px, 4.6vw, 34px);
  line-height: 1.24;
  letter-spacing: 0.01em;
  color: var(--chalk);
}

.page-about .about-sec__lead {
  margin: 0 0 clamp(20px, 3vw, 28px);
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--concrete);
}

/* 双栏文字块 */
.page-about .about-split {
  display: grid;
  gap: clamp(20px, 3vw, 32px);
}

.page-about .about-split__text p {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.9;
  color: var(--concrete);
}

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

.page-about .about-split__text a {
  color: var(--signal);
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 107, 26, 0.45);
}

.page-about .about-split__text a:hover,
.page-about .about-split__text a:focus-visible {
  color: var(--lemon);
  border-bottom-color: var(--lemon);
}

/* 观赛动线 */
.page-about .about-route {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  align-content: start;
}

.page-about .about-route__item {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 14px 16px;
  background: var(--ink);
  font-size: 14px;
  line-height: 1.5;
  color: var(--chalk);
}

.page-about .about-route__idx {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--signal);
}

/* 内容体系 */
.page-about .about-system {
  display: grid;
  gap: clamp(20px, 3vw, 28px);
}

.page-about .about-system__figure {
  margin: 0;
  border: 1px solid var(--line-mid);
  background: var(--ink-deep);
}

.page-about .about-system__figure .media {
  border: 0;
}

.page-about .about-system__figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(0.7) brightness(0.9);
}

.page-about .about-system__caption {
  padding: 10px 12px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--mist);
}

.page-about .about-flow {
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-flow__item {
  background: var(--ink);
  padding: 18px 18px 20px;
  border-left: 2px solid transparent;
  transition: border-color 0.25s var(--ease), background 0.25s var(--ease);
}

.page-about .about-flow__item:hover,
.page-about .about-flow__item:focus-within {
  border-left-color: var(--signal);
  background: var(--steel);
}

.page-about .about-flow__item h3 {
  margin: 10px 0 8px;
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--chalk);
}

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

/* 团队 */
.page-about .about-team {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--line-mid);
}

.page-about .about-team__row {
  display: grid;
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-team__name {
  font-family: var(--font-head);
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--signal);
}

.page-about .about-team__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--concrete);
}

.page-about .about-team__tag {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--mist);
}

.page-about .about-facts {
  list-style: none;
  margin: clamp(20px, 3vw, 28px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(1, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-facts li {
  background: var(--ink-deep);
  padding: 14px 16px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--mist);
}

.page-about .about-facts strong {
  display: block;
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--lemon);
  margin-bottom: 2px;
}

/* 时间线 */
.page-about .about-timeline {
  position: relative;
  padding: clamp(14px, 3vw, 26px) 0 clamp(6px, 2vw, 14px);
  isolation: isolate;
}

.page-about .about-tl-bg {
  position: absolute;
  inset: 0;
  margin: 0;
  z-index: -1;
  overflow: hidden;
  border: 1px solid var(--line);
}

.page-about .about-tl-bg img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.16;
  filter: grayscale(0.3);
}

.page-about .tl-item {
  border-left: 2px solid var(--steel);
  padding: 0 0 0 clamp(14px, 2.4vw, 20px);
  margin-bottom: 14px;
  background: rgba(14, 27, 22, 0.72);
  transition: border-color 0.25s var(--ease);
}

.page-about .tl-item[open] {
  border-left-color: var(--signal);
}

.page-about .tl-item__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 16px;
  padding: 12px 14px 12px 0;
  cursor: pointer;
  list-style: none;
}

.page-about .tl-item__head::-webkit-details-marker {
  display: none;
}

.page-about .tl-item__head::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--mist);
}

.page-about .tl-item[open] .tl-item__head::after {
  content: "−";
  color: var(--signal);
}

.page-about .tl-item__year {
  font-size: clamp(24px, 5vw, 34px);
  line-height: 1;
}

.page-about .tl-item__label {
  font-size: 14px;
  letter-spacing: 0.04em;
  color: var(--chalk);
}

.page-about .tl-item__body {
  padding: 0 16px 16px 0;
}

.page-about .tl-item__body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--concrete);
}

/* 合作 */
.page-about .about-support {
  border: 1px solid var(--line-mid);
  padding: 18px;
  background: var(--ink-deep);
}

.page-about .about-support__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--moss);
}

.page-about .about-support__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-support__list li {
  position: relative;
  padding-left: 16px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--concrete);
}

.page-about .about-support__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 7px;
  height: 1px;
  background: var(--signal);
}

/* 结尾 */
.page-about .about-cta {
  margin-top: clamp(26px, 4vw, 40px);
  display: grid;
  gap: 18px;
  padding: clamp(20px, 3.4vw, 30px);
  border: 1px solid var(--line-mid);
  background: linear-gradient(115deg, rgba(255, 107, 26, 0.14), rgba(14, 27, 22, 0) 62%);
}

.page-about .about-cta__kicker {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  color: var(--signal);
}

.page-about .about-cta__text {
  margin: 0;
  max-width: 44ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--chalk);
}

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

/* 平板 */
@media (min-width: 42em) {
  .page-about .about-hero__meta {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

  .page-about .about-team__row {
    grid-template-columns: 140px minmax(0, 1fr);
    align-items: start;
    gap: 6px 20px;
  }

  .page-about .about-team__tag {
    grid-column: 2;
  }

  .page-about .about-cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
  }
}

/* 桌面 */
@media (min-width: 64em) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
    align-items: end;
  }

  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    column-gap: clamp(28px, 4vw, 56px);
  }

  .page-about .about-rail {
    display: block;
    position: sticky;
    top: 104px;
    align-self: start;
    padding-top: clamp(18px, 2vw, 26px);
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-split--partner {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  }

  .page-about .about-system {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    align-items: start;
  }

  .page-about .about-sec__num {
    font-size: clamp(54px, 5vw, 72px);
  }

  .page-about .tl-item__body p {
    max-width: 62ch;
  }
}

/* 减少动态偏好 */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-flow__item,
  .page-about .tl-item {
    transition: none;
  }
}
<<<END>>>