.page-about {
  --about-measure: 62ch;
  background: var(--tt-space);
  color: var(--tt-silver-2);
  font-family: var(--tt-font);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(24px, 5vw, 52px) 0 clamp(34px, 6vw, 76px);
  background:
    radial-gradient(110% 82% at 88% -18%, rgba(255, 90, 31, 0.18), rgba(255, 90, 31, 0) 62%),
    linear-gradient(176deg, var(--tt-space) 0%, var(--tt-carbon) 100%);
  border-bottom: 1px solid var(--tt-line);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(26px, 4vw, 44px);
  margin-top: clamp(20px, 3.5vw, 34px);
}

.page-about .about-hero__title {
  margin: 14px 0 0;
  max-width: 20ch;
  font-size: clamp(30px, 5.4vw, 58px);
  font-weight: 800;
  line-height: 1.12;
  letter-spacing: -0.01em;
  color: var(--tt-silver-2);
}

.page-about .about-hero__lede {
  margin: 18px 0 0;
  max-width: 54ch;
  font-size: clamp(16px, 1.6vw, 18px);
  line-height: 1.85;
  color: rgba(233, 237, 242, 0.82);
}

.page-about .about-hero__signal {
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .about-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
  border-top: 1px solid var(--tt-line);
}

.page-about .about-facts > li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: baseline;
  gap: 16px;
  padding: 14px 2px;
  border-bottom: 1px solid var(--tt-line);
}

.page-about .about-facts .tt-evidence__num {
  font-family: var(--tt-font-num);
  font-size: clamp(26px, 3.4vw, 34px);
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--tt-orange);
}

.page-about .about-facts .tt-evidence__tag {
  display: block;
  font-size: 13px;
  line-height: 1.7;
  letter-spacing: 0.03em;
  color: rgba(233, 237, 242, 0.72);
}

/* ---------- 主体骨架 ---------- */
.page-about .about-body {
  padding: clamp(36px, 6vw, 84px) 0 clamp(56px, 9vw, 120px);
}

.page-about .about-body__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(30px, 4vw, 60px);
}

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

.page-about .about-rail__label {
  margin: 0 0 12px;
  color: rgba(233, 237, 242, 0.42);
}

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

.page-about .tt-rail__item + .tt-rail__item {
  margin-top: 2px;
}

.page-about .tt-rail__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 9px 12px 9px 14px;
  border-left: 1px solid var(--tt-line);
  color: rgba(233, 237, 242, 0.56);
  font-size: 13px;
  letter-spacing: 0.03em;
  text-decoration: none;
  transition: color 0.22s ease-out, background-color 0.22s ease-out, border-color 0.22s ease-out;
}

.page-about .tt-rail__link .tt-num {
  font-family: var(--tt-font-num);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--tt-mist);
}

.page-about .tt-rail__link:hover,
.page-about .tt-rail__link:focus-visible {
  color: var(--tt-silver-2);
  border-left-color: var(--tt-orange);
}

.page-about .tt-rail__item.is-active .tt-rail__link {
  background: var(--tt-cream);
  color: var(--tt-carbon);
  border-left-color: var(--tt-orange);
}

.page-about .tt-rail__item.is-active .tt-rail__link .tt-num {
  color: var(--tt-orange-deep);
}

.page-about .about-flow {
  max-width: 780px;
}

/* ---------- 章节排版 ---------- */
.page-about .about-chapter + .about-chapter {
  margin-top: clamp(56px, 9vw, 124px);
}

.page-about .about-chapter__head {
  margin-bottom: clamp(18px, 3vw, 30px);
}

.page-about .about-chapter__num {
  display: block;
  font-family: var(--tt-font-narrow);
  font-weight: 700;
  font-size: clamp(60px, 12vw, 118px);
  line-height: 0.82;
  letter-spacing: -0.03em;
  color: rgba(198, 205, 214, 0.2);
  -webkit-text-stroke: 1px var(--tt-line-strong);
}

.page-about .about-chapter__title {
  margin: 10px 0 0;
  font-size: clamp(25px, 3.6vw, 40px);
  font-weight: 800;
  line-height: 1.24;
  letter-spacing: -0.01em;
  color: var(--tt-silver-2);
}

.page-about .about-prose {
  max-width: var(--about-measure);
  font-size: 17px;
  line-height: 1.88;
  color: rgba(233, 237, 242, 0.84);
}

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

.page-about .about-prose p + p {
  margin-top: 1.15em;
}

.page-about .about-prose--ink {
  color: rgba(20, 23, 28, 0.78);
}

/* ---------- 图片 ---------- */
.page-about .about-figure {
  margin: 0 0 clamp(24px, 4vw, 40px);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--tt-radius);
  border: 1px solid var(--tt-line);
  background: var(--tt-rock);
  filter: saturate(0.92) contrast(1.04);
}

.page-about .about-figure figcaption {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  letter-spacing: 0.03em;
  color: rgba(233, 237, 242, 0.54);
}

/* ---------- 岗位节点 ---------- */
.page-about .about-crew {
  list-style: none;
  margin: clamp(22px, 3.5vw, 34px) 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-crew__node {
  position: relative;
  padding: clamp(16px, 2.4vw, 22px) clamp(16px, 2.4vw, 24px);
  background: var(--tt-rock);
  border: 1px solid var(--tt-line);
  border-radius: var(--tt-radius-soft);
  transition: border-color 0.24s ease-out, transform 0.24s ease-out, background-color 0.24s ease-out;
}

.page-about .about-crew__node::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 18px;
  width: 3px;
  height: 26px;
  background: var(--tt-mist);
  transition: background-color 0.24s ease-out;
}

.page-about .about-crew__node:hover,
.page-about .about-crew__node:focus-within {
  transform: translateX(4px);
  border-color: var(--tt-line-strong);
}

.page-about .about-crew__node:hover::before,
.page-about .about-crew__node:focus-within::before {
  background: var(--tt-orange);
}

.page-about .about-crew__code {
  display: block;
  font-family: var(--tt-font-num);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--tt-orange);
}

.page-about .about-crew__role {
  margin: 8px 0 0;
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--tt-silver-2);
}

.page-about .about-crew__duty {
  margin: 8px 0 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.82;
  color: rgba(233, 237, 242, 0.72);
}

.page-about .about-crew__note {
  margin: clamp(20px, 3vw, 30px) 0 0;
  max-width: var(--about-measure);
  padding-left: 18px;
  border-left: 1px solid var(--tt-line-strong);
  font-size: 15px;
  line-height: 1.88;
  color: rgba(233, 237, 242, 0.68);
}

/* ---------- 流程步骤 ---------- */
.page-about .about-flowlist {
  list-style: none;
  margin: clamp(24px, 4vw, 38px) 0 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .about-flowlist__step {
  position: relative;
  padding: 0 0 clamp(20px, 3vw, 30px) 42px;
}

.page-about .about-flowlist__step::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 6px;
  bottom: 0;
  width: 1px;
  background-image: linear-gradient(180deg, var(--tt-line-strong) 0 5px, transparent 5px 11px);
  background-size: 1px 11px;
}

.page-about .about-flowlist__step:last-child::before {
  background-image: linear-gradient(180deg, var(--tt-line-strong) 0 5px, transparent 5px 11px);
  bottom: 40%;
  opacity: 0.5;
}

.page-about .about-flowlist__idx {
  position: absolute;
  left: 0;
  top: 0;
  width: 20px;
  font-family: var(--tt-font-num);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--tt-orange);
}

.page-about .about-flowlist__name {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  color: var(--tt-silver-2);
}

.page-about .about-flowlist__desc {
  margin: 7px 0 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.84;
  color: rgba(233, 237, 242, 0.72);
}

/* ---------- 米白色时间轴面板 ---------- */
.page-about .about-panel--cream {
  background: var(--tt-cream);
  color: var(--tt-carbon);
  border-radius: var(--tt-radius-soft);
  padding: clamp(24px, 4.4vw, 52px);
  margin-left: calc(-1 * clamp(0px, 1vw, 8px));
}

.page-about .about-panel--cream .about-chapter__num {
  color: rgba(20, 23, 28, 0.12);
  -webkit-text-stroke-color: rgba(20, 23, 28, 0.24);
}

.page-about .about-panel--cream .about-chapter__title {
  color: var(--tt-carbon);
}

.page-about .about-timeline {
  list-style: none;
  margin: clamp(26px, 4vw, 40px) 0 0;
  padding: 0 0 0 32px;
  position: relative;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 12px;
  width: 1px;
  background: linear-gradient(180deg, var(--tt-orange-deep) 0%, rgba(20, 23, 28, 0.22) 100%);
}

.page-about .about-timeline__item {
  position: relative;
  padding-bottom: clamp(24px, 4vw, 40px);
  transition: transform 0.26s ease-out;
}

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

.page-about .about-timeline__item::before {
  content: "";
  position: absolute;
  left: -32px;
  top: 7px;
  width: 9px;
  height: 9px;
  background: var(--tt-orange-deep);
  transform: rotate(45deg);
}

.page-about .about-timeline__item:hover {
  transform: translateX(5px);
}

.page-about .about-timeline__year {
  display: block;
  font-family: var(--tt-font-num);
  font-size: 13px;
  letter-spacing: 0.14em;
  color: var(--tt-moss);
}

.page-about .about-timeline__name {
  margin: 5px 0 0;
  font-size: clamp(18px, 2.2vw, 22px);
  font-weight: 700;
  color: var(--tt-carbon);
}

.page-about .about-timeline__desc {
  margin: 8px 0 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.86;
  color: rgba(20, 23, 28, 0.74);
}

/* ---------- 合作网络 ---------- */
.page-about .about-network__stats {
  display: grid;
  gap: 1px;
  margin: clamp(24px, 3.6vw, 36px) 0 clamp(24px, 3.6vw, 36px);
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  background: var(--tt-line);
  border-top: 1px solid var(--tt-line);
  border-bottom: 1px solid var(--tt-line);
}

.page-about .about-network__stat {
  background: var(--tt-space);
  padding: 18px 4px;
}

.page-about .about-network__num {
  display: block;
  font-family: var(--tt-font-num);
  font-size: clamp(34px, 5vw, 48px);
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--tt-sun);
}

.page-about .about-network__cap {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: rgba(233, 237, 242, 0.66);
}

.page-about .about-network__ways {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-network__ways li {
  padding: 18px 20px;
  border: 1px solid var(--tt-line);
  border-left: 2px solid var(--tt-mist);
  border-radius: var(--tt-radius-soft);
  background: linear-gradient(120deg, rgba(110, 139, 122, 0.1), rgba(110, 139, 122, 0) 62%);
}

.page-about .about-network__ways h3 {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  color: var(--tt-silver-2);
}

.page-about .about-network__ways p {
  margin: 8px 0 0;
  max-width: 58ch;
  font-size: 15px;
  line-height: 1.82;
  color: rgba(233, 237, 242, 0.72);
}

/* ---------- 资料库字段 ---------- */
.page-about .about-archive__fields {
  list-style: none;
  margin: clamp(22px, 3.4vw, 34px) 0;
  padding: 0;
  display: grid;
  gap: 10px;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
}

.page-about .about-archive__fields li {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 14px 16px;
  background: var(--tt-carbon);
  border: 1px solid var(--tt-line);
  border-radius: var(--tt-radius);
  font-size: 15px;
  color: rgba(233, 237, 242, 0.86);
}

.page-about .about-archive__fields .tt-num {
  font-family: var(--tt-font-num);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--tt-orange);
}

.page-about .about-inline {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(22px, 3.4vw, 32px);
}

/* ---------- 结尾引导 ---------- */
.page-about .about-cta {
  position: relative;
  padding: clamp(38px, 6vw, 76px) 0 clamp(44px, 7vw, 92px);
  background: linear-gradient(150deg, var(--tt-carbon) 0%, var(--tt-space) 62%, var(--tt-carbon) 100%);
  border-top: 1px solid var(--tt-line);
}

.page-about .about-cta__inner {
  display: grid;
  gap: clamp(22px, 3.4vw, 36px);
}

.page-about .about-cta__title {
  margin: 0;
  font-size: clamp(23px, 3.4vw, 36px);
  font-weight: 800;
  line-height: 1.26;
  letter-spacing: -0.01em;
  color: var(--tt-silver-2);
  max-width: 22ch;
}

.page-about .about-cta__text p {
  margin: 14px 0 0;
  max-width: 52ch;
  font-size: 16px;
  line-height: 1.84;
  color: rgba(233, 237, 242, 0.74);
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-self: end;
}

/* ---------- 响应式 ---------- */
@media (min-width: 960px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.45fr) minmax(240px, 0.75fr);
    align-items: end;
    gap: clamp(36px, 5vw, 76px);
  }

  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 1.2fr) auto;
    align-items: end;
  }
}

@media (min-width: 1000px) {
  .page-about .about-body__grid {
    grid-template-columns: 176px minmax(0, 1fr);
    gap: clamp(40px, 5vw, 84px);
    align-items: start;
  }

  .page-about .about-rail {
    display: block;
    position: sticky;
    top: 104px;
  }
}

@media (min-width: 1200px) {
  .page-about .about-flow {
    max-width: 820px;
  }
}

@media (max-width: 560px) {
  .page-about .about-facts > li {
    grid-template-columns: minmax(0, 1fr);
    gap: 4px;
  }

  .page-about .about-panel--cream {
    margin-left: 0;
    border-radius: var(--tt-radius);
  }

  .page-about .about-network__ways li {
    padding: 16px 16px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-crew__node,
  .page-about .about-timeline__item,
  .page-about .tt-rail__link {
    transition: none;
  }

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