.page-about {
  position: relative;
  background-color: var(--ink);
  background-image:
    linear-gradient(rgba(198, 207, 202, .05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(198, 207, 202, .05) 1px, transparent 1px);
  background-size: 48px 48px;
  background-position: -1px -1px;
  color: var(--paper);
  overflow-x: clip;
}

.page-about .about-crumbs {
  padding-top: 20px;
  padding-bottom: 20px;
}

/* ---------- 首屏 ---------- */

.page-about .hero {
  position: relative;
  padding: 16px 0 64px;
  isolation: isolate;
}

.page-about .hero::before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 62%;
  height: 300px;
  background: linear-gradient(158deg, var(--green) 0%, rgba(18, 59, 46, 0) 72%);
  clip-path: polygon(14% 0, 100% 0, 100% 100%, 0 100%);
  pointer-events: none;
  z-index: 0;
}

.page-about .hero > .wrap {
  position: relative;
  z-index: 1;
}

.page-about .hero__grid {
  display: grid;
  gap: 32px;
}

.page-about .hero__annot {
  margin: 0 0 20px;
  font-size: var(--t-12);
  letter-spacing: .28em;
  text-transform: uppercase;
  color: var(--ice);
}

.page-about .hero__title {
  margin: 0 0 22px;
  font-family: var(--font-sans);
  font-weight: 900;
  font-size: clamp(40px, 8.4vw, 92px);
  line-height: .94;
  letter-spacing: -.04em;
  color: var(--paper);
}

.page-about .hero__title .hl {
  color: var(--orange);
}

.page-about .hero__text {
  max-width: 56ch;
  margin: 0 0 28px;
  font-size: var(--t-18);
  line-height: 1.75;
  color: var(--silver);
}

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

.page-about .hero__figure {
  margin: 0;
  border: 1px solid var(--line-2);
  background: var(--rock);
}

.page-about .hero__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.page-about .hero__stats {
  list-style: none;
  margin: 48px 0 0;
  padding: 24px 0 0;
  border-top: 1px solid var(--line-2);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px 16px;
}

.page-about .hero__stats .stat {
  display: block;
}

.page-about .hero__stats .stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 5vw, 42px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--paper);
  font-variant-numeric: tabular-nums;
}

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

.page-about .hero__stats .stat__label {
  display: block;
  margin-top: 10px;
  font-size: var(--t-12);
  letter-spacing: .16em;
  color: var(--sunk);
}

@media (min-width: 900px) {
  .page-about .hero {
    padding: 32px 0 96px;
  }

  .page-about .hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 56px;
    align-items: end;
  }

  .page-about .hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    margin-top: 64px;
  }
}

/* ---------- 章节通用 ---------- */

.page-about .section {
  position: relative;
  padding: 64px 0;
}

.page-about .section__head {
  margin-bottom: 36px;
}

.page-about .section__num {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: var(--t-14);
  letter-spacing: .28em;
  color: var(--orange);
}

.page-about .section__title {
  margin: 0;
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: clamp(24px, 4.4vw, 42px);
  line-height: 1.16;
  letter-spacing: -.02em;
  color: var(--paper);
}

.page-about .section__note {
  max-width: 56ch;
  margin: 14px 0 0;
  font-size: var(--t-14);
  line-height: 1.7;
  color: var(--sunk);
}

@media (min-width: 900px) {
  .page-about .section {
    padding: 104px 0;
  }

  .page-about .section__head {
    margin-bottom: 48px;
  }
}

/* ---------- 01 起点 ---------- */

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

.page-about .origin__grid {
  display: grid;
  gap: 32px;
}

.page-about .origin__body p {
  margin: 0 0 18px;
  max-width: 62ch;
  font-size: var(--t-18);
  line-height: 1.78;
  color: var(--silver);
}

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

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

.page-about .origin__item {
  background: var(--rock);
  padding: 24px 20px;
}

.page-about .origin__item-title {
  margin: 0 0 8px;
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: var(--t-24);
  color: var(--paper);
}

.page-about .origin__item p {
  margin: 0;
  font-size: var(--t-14);
  line-height: 1.7;
  color: var(--sunk);
}

@media (min-width: 900px) {
  .page-about .origin__grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 6fr);
    gap: 56px;
    align-items: start;
  }
}

/* ---------- 02 时间线 ---------- */

.page-about .tabs__panel[hidden] {
  display: none;
}

.page-about .tabs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 1px;
  margin-bottom: 40px;
  background: var(--line);
  border: 1px solid var(--line);
  width: max-content;
  max-width: 100%;
}

.page-about .tabs__btn {
  appearance: none;
  border: 0;
  background: var(--ink);
  color: var(--sunk);
  font-family: var(--font-mono);
  font-size: var(--t-14);
  letter-spacing: .14em;
  padding: 12px 22px;
  cursor: pointer;
  transition: color .2s ease, background-color .2s ease;
}

.page-about .tabs__btn:hover {
  color: var(--paper);
}

.page-about .tabs__btn[aria-selected="true"] {
  background: var(--green);
  color: var(--orange);
  box-shadow: inset 0 -3px 0 0 var(--orange);
}

.page-about .tabs__btn:focus-visible {
  outline: 2px solid var(--ice);
  outline-offset: -2px;
}

.page-about .tl {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 30px;
}

.page-about .tl__item {
  display: grid;
  gap: 10px;
}

.page-about .tl__year {
  display: flex;
  align-items: center;
  gap: 12px;
}

.page-about .tl__yr {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(40px, 10vw, 68px);
  line-height: .9;
  letter-spacing: -.035em;
  color: var(--ember);
  font-variant-numeric: tabular-nums;
  transition: color .45s ease;
}

@supports (-webkit-text-stroke: 1px red) {
  .page-about .tl__yr {
    color: transparent;
    -webkit-text-stroke: 1px rgba(255, 106, 19, .78);
  }

  .page-about .tl__item:hover .tl__yr,
  .page-about .tl__item:focus-within .tl__yr,
  .page-about .tl__item.is-in .tl__yr {
    color: var(--orange);
  }
}

.page-about .tl__badge {
  font-size: var(--t-12);
  letter-spacing: .16em;
}

.page-about .tl__body {
  position: relative;
  padding-left: 26px;
}

.page-about .tl__body::before {
  content: "";
  position: absolute;
  left: 0;
  top: 9px;
  width: 9px;
  height: 9px;
  background: var(--orange);
}

.page-about .tl__body::after {
  content: "";
  position: absolute;
  left: 4px;
  top: 24px;
  bottom: -32px;
  width: 1px;
  background: var(--line-2);
}

.page-about .tl__item:last-child .tl__body::after {
  display: none;
}

.page-about .tl__title {
  margin: 0 0 8px;
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: var(--t-24);
  line-height: 1.3;
  color: var(--paper);
}

.page-about .tl__body p {
  margin: 0;
  max-width: 60ch;
  font-size: var(--t-18);
  line-height: 1.72;
  color: var(--silver);
}

@media (min-width: 860px) {
  .page-about .tl {
    gap: 44px;
  }

  .page-about .tl__item {
    grid-template-columns: 240px minmax(0, 1fr);
    gap: 40px;
    align-items: start;
  }

  .page-about .tl__year {
    justify-content: flex-start;
  }
}

/* ---------- 03 团队 ---------- */

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

.page-about .crew__top {
  display: grid;
  gap: 28px;
  margin-bottom: 40px;
}

.page-about .crew__figure {
  margin: 0;
  border: 1px solid var(--line-2);
  background: var(--rock);
}

.page-about .crew__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

.page-about .crew__bars-title {
  margin: 0 0 18px;
  font-size: var(--t-14);
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--sunk);
}

.page-about .crew__bars {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .bar {
  display: grid;
  grid-template-columns: 92px minmax(0, 1fr) 34px;
  align-items: center;
  gap: 12px;
}

.page-about .bar__label {
  font-size: var(--t-14);
  color: var(--silver);
}

.page-about .bar__track {
  display: block;
  position: relative;
  height: 8px;
  background: rgba(198, 207, 202, .12);
}

.page-about .bar__fill {
  display: block;
  height: 100%;
  background: var(--orange);
}

.page-about .bar--1 .bar__fill { width: 100%; }
.page-about .bar--2 .bar__fill { width: 88.8%; background: var(--ember); }
.page-about .bar--3 .bar__fill { width: 66.6%; background: var(--ice); }
.page-about .bar--4 .bar__fill { width: 33.3%; background: var(--moss); }

.page-about .bar__num {
  font-family: var(--font-mono);
  font-size: var(--t-18);
  text-align: right;
  color: var(--paper);
  font-variant-numeric: tabular-nums;
}

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

.page-about .crew__card {
  background: var(--rock);
  padding: 24px 20px;
  outline: none;
  border-left: 3px solid transparent;
  transition: border-color .25s ease, background-color .25s ease;
}

.page-about .crew__card:hover,
.page-about .crew__card:focus-within,
.page-about .crew__card:focus-visible {
  border-left-color: var(--orange);
  background: var(--green);
}

.page-about .crew__name {
  margin: 0 0 10px;
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-family: var(--font-sans);
  font-weight: 800;
  font-size: var(--t-24);
  line-height: 1.25;
  color: var(--paper);
}

.page-about .crew__count {
  font-family: var(--font-mono);
  font-size: var(--t-14);
  color: var(--orange);
  letter-spacing: .06em;
}

.page-about .crew__lead {
  margin: 0;
  font-size: var(--t-14);
  line-height: 1.7;
  color: var(--silver);
}

.page-about .crew__more {
  max-height: 0;
  overflow: hidden;
  transition: max-height .4s ease;
}

.page-about .crew__card:hover .crew__more,
.page-about .crew__card:focus-within .crew__more,
.page-about .crew__card:focus-visible .crew__more {
  max-height: 260px;
}

.page-about .crew__more p {
  margin: 14px 0 0;
  padding-top: 14px;
  border-top: 1px solid var(--line-2);
  font-size: var(--t-14);
  line-height: 1.7;
  color: var(--sunk);
}

@media (min-width: 900px) {
  .page-about .crew__top {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 48px;
    align-items: center;
  }

  .page-about .crew {
    grid-template-columns: repeat(12, minmax(0, 1fr));
  }

  .page-about .crew__card:nth-child(1) { grid-column: span 5; }
  .page-about .crew__card:nth-child(2) { grid-column: span 7; }
  .page-about .crew__card:nth-child(3) { grid-column: span 7; }
  .page-about .crew__card:nth-child(4) { grid-column: span 5; }

  .page-about .crew__card {
    padding: 32px 28px;
  }
}

/* 移动端：没有悬停，展开内容直接可见 */
@media (hover: none) {
  .page-about .crew__more {
    max-height: none;
  }
}

/* ---------- 04 数据 ---------- */

.page-about .data-sec {
  background: var(--green);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .data-sec .section__title {
  color: var(--paper);
}

.page-about .data__grid {
  display: grid;
  gap: 32px;
}

.page-about .data__big {
  display: flex;
  flex-direction: column;
  padding: 28px 24px;
  background: var(--ink);
  border: 1px solid var(--line-2);
}

.page-about .data__big-num {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(48px, 12vw, 96px);
  line-height: .92;
  letter-spacing: -.04em;
  color: var(--orange);
  font-variant-numeric: tabular-nums;
}

.page-about .data__big-unit {
  margin-top: 10px;
  font-size: var(--t-14);
  letter-spacing: .24em;
  color: var(--sunk);
}

.page-about .data__big-text {
  margin: 22px 0 0;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: var(--t-18);
  line-height: 1.72;
  color: var(--silver);
}

.page-about .data__side {
  display: grid;
  gap: 1px;
  background: var(--line-2);
  border: 1px solid var(--line-2);
}

.page-about .data__row {
  display: grid;
  grid-template-columns: 78px minmax(0, 1fr);
  gap: 16px;
  align-items: start;
  padding: 22px 20px;
  background: var(--rock);
}

.page-about .data__row-num {
  font-family: var(--font-mono);
  font-size: var(--t-34);
  font-weight: 700;
  line-height: 1;
  color: var(--ice);
  font-variant-numeric: tabular-nums;
}

.page-about .data__row-text {
  margin: 0;
  font-size: var(--t-14);
  line-height: 1.7;
  color: var(--silver);
}

@media (min-width: 900px) {
  .page-about .data__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: 1px;
    background: var(--line-2);
    border: 1px solid var(--line-2);
  }

  .page-about .data__big {
    border: 0;
    padding: 40px 32px;
  }

  .page-about .data__side {
    border: 0;
  }
}

/* ---------- 05 长期跟队 ---------- */

.page-about .follow__grid {
  display: grid;
  gap: 36px;
}

.page-about .follow__body p {
  max-width: 58ch;
  margin: 18px 0 22px;
  font-size: var(--t-18);
  line-height: 1.76;
  color: var(--silver);
}

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

.page-about .follow__item {
  background: var(--rock);
  padding: 22px 20px;
}

.page-about .follow__num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--t-34);
  font-weight: 700;
  line-height: 1;
  color: var(--orange);
  font-variant-numeric: tabular-nums;
}

.page-about .follow__item-title {
  margin: 10px 0 6px;
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: var(--t-18);
  color: var(--paper);
}

.page-about .follow__item p {
  margin: 0;
  font-size: var(--t-14);
  line-height: 1.7;
  color: var(--sunk);
}

@media (min-width: 900px) {
  .page-about .follow__grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 6fr);
    gap: 64px;
    align-items: start;
  }

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

/* ---------- 06 吉林基地 ---------- */

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

.page-about .geo__grid {
  display: grid;
  gap: 32px;
}

.page-about .geo__figure {
  margin: 0;
  border: 1px solid var(--line-2);
  background: var(--rock);
}

.page-about .geo__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.page-about .geo__body p {
  max-width: 58ch;
  margin: 0 0 18px;
  font-size: var(--t-18);
  line-height: 1.76;
  color: var(--silver);
}

.page-about .geo__facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin: 28px 0 0;
  padding-top: 24px;
  border-top: 1px solid var(--line-2);
}

.page-about .geo__fact dt {
  font-size: var(--t-12);
  letter-spacing: .18em;
  color: var(--sunk);
}

.page-about .geo__fact dd {
  margin: 8px 0 0;
  font-size: var(--t-18);
  font-weight: 700;
  color: var(--paper);
}

@media (min-width: 900px) {
  .page-about .geo__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    gap: 56px;
    align-items: center;
  }
}

/* ---------- 07 流程 ---------- */

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

.page-about .flow__step {
  background: var(--ink);
  padding: 26px 20px;
  border-top: 2px solid transparent;
  transition: border-color .25s ease;
}

.page-about .flow__step:hover {
  border-top-color: var(--orange);
}

.page-about .flow__num {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--t-14);
  letter-spacing: .26em;
  color: var(--orange);
}

.page-about .flow__title {
  margin: 12px 0 8px;
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: var(--t-18);
  color: var(--paper);
}

.page-about .flow__step p {
  margin: 0;
  font-size: var(--t-14);
  line-height: 1.72;
  color: var(--sunk);
}

@media (min-width: 820px) {
  .page-about .flow {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .flow__step {
    padding: 32px 24px;
  }
}

/* ---------- 收尾 ---------- */

.page-about .closing {
  padding-bottom: 88px;
}

.page-about .closing__inner {
  position: relative;
  padding: 40px 24px;
  background: var(--rock);
  border: 1px solid var(--line-2);
  overflow: hidden;
}

.page-about .closing__inner::after {
  content: "";
  position: absolute;
  right: -60px;
  bottom: -90px;
  width: 220px;
  height: 220px;
  background: var(--green);
  transform: rotate(10deg);
  pointer-events: none;
}

.page-about .closing__title {
  position: relative;
  z-index: 1;
  margin: 0 0 16px;
  font-family: var(--font-sans);
  font-weight: 900;
  font-size: clamp(26px, 5vw, 48px);
  line-height: 1.14;
  letter-spacing: -.02em;
  color: var(--paper);
}

.page-about .closing__text {
  position: relative;
  z-index: 1;
  max-width: 56ch;
  margin: 0 0 26px;
  font-size: var(--t-18);
  line-height: 1.75;
  color: var(--silver);
}

.page-about .closing__actions {
  position: relative;
  z-index: 1;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

@media (min-width: 900px) {
  .page-about .closing {
    padding-bottom: 120px;
  }

  .page-about .closing__inner {
    padding: 64px 56px;
  }
}

/* ---------- 无障碍 ---------- */

.page-about .btn:focus-visible,
.page-about .crew__card:focus-visible,
.page-about .flow__step:focus-visible {
  outline: 2px solid var(--ice);
  outline-offset: 3px;
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
  }
}