.page-about {
  --about-idx: 250px;
  --about-rule: rgba(15, 20, 24, 0.12);
  background: var(--sand-100);
  color: var(--ink-900);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  color: #fff;
  padding: clamp(26px, 4.5vw, 58px) 0 clamp(40px, 6vw, 82px);
  background:
    radial-gradient(780px 430px at 84% -16%, rgba(111, 180, 206, 0.38), transparent 66%),
    radial-gradient(560px 350px at 6% 112%, rgba(255, 106, 69, 0.22), transparent 62%),
    linear-gradient(168deg, var(--ocean-900) 0%, var(--ocean-950) 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image: radial-gradient(rgba(255, 255, 255, 0.09) 0.5px, transparent 0.7px);
  background-size: 4px 4px;
  opacity: 0.55;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__crumbs {
  margin: 0 0 22px;
}

.page-about .about-hero__crumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: var(--step--1);
  color: rgba(255, 255, 255, 0.58);
}

.page-about .about-hero__crumbs li + li::before {
  content: "/";
  margin-right: 8px;
  color: rgba(255, 255, 255, 0.3);
}

.page-about .about-hero__crumbs a {
  color: rgba(255, 255, 255, 0.78);
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 255, 255, 0.24);
}

.page-about .about-hero__crumbs a:hover,
.page-about .about-hero__crumbs a:focus-visible {
  color: var(--coral-500);
  border-bottom-color: var(--coral-500);
}

.page-about .about-hero__eyebrow {
  margin: 0;
  color: var(--coral-500);
  font-family: var(--font-narrow);
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.page-about .about-hero__title {
  margin: 12px 0 20px;
  max-width: 18ch;
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(30px, 5.6vw, 66px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: #fff;
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 60ch;
  font-size: var(--step-1);
  line-height: 1.75;
  color: rgba(255, 255, 255, 0.82);
}

.page-about .about-figs {
  margin: 28px 0 0;
  padding: 18px 20px;
  display: grid;
  gap: 14px;
  border-radius: var(--radius);
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: rgba(255, 255, 255, 0.07);
  backdrop-filter: blur(8px);
}

.page-about .about-figs__item {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.page-about .about-figs dt {
  font-family: var(--font-narrow);
  font-size: var(--step--1);
  letter-spacing: 0.08em;
  color: rgba(255, 255, 255, 0.6);
}

.page-about .about-figs dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--step-1);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  color: #fff;
}

@media (min-width: 960px) {
  .page-about .about-hero__inner {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 320px;
    column-gap: clamp(32px, 5vw, 76px);
    row-gap: 0;
    align-items: end;
  }
  .page-about .about-hero__crumbs { grid-column: 1 / -1; }
  .page-about .about-hero__lead { grid-column: 1; }
  .page-about .about-figs {
    grid-column: 2;
    margin-top: 0;
  }
}

/* ---------- 主体骨架 ---------- */
.page-about .about-layout {
  padding-top: clamp(34px, 5vw, 68px);
  padding-bottom: clamp(52px, 7vw, 104px);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 56px);
  align-items: start;
}

@media (min-width: 960px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-idx) minmax(0, 1fr);
  }
}

/* ---------- 章节索引 ---------- */
.page-about .about-index {
  border-radius: var(--radius-lg);
  border: 1px solid var(--about-rule);
  background: rgba(255, 255, 255, 0.78);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-soft);
  padding: 16px;
}

@media (min-width: 960px) {
  .page-about .about-index {
    position: sticky;
    top: 22px;
  }
}

.page-about .about-index__title {
  margin: 0 0 12px;
  font-family: var(--font-narrow);
  font-weight: 700;
  font-size: var(--step--1);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ocean-600);
}

.page-about .about-index__list {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-index__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 8px 10px;
  border-left: 2px solid transparent;
  border-radius: 10px;
  color: var(--ink-soft);
  font-size: var(--step--1);
  line-height: 1.5;
  text-decoration: none;
  transition: background var(--speed) ease, color var(--speed) ease, border-color var(--speed) ease;
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  background: var(--coral-050);
  border-left-color: var(--coral-500);
  color: var(--ink-900);
}

.page-about .about-index__num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--ocean-300);
}

@media (max-width: 959px) {
  .page-about .about-index__list {
    flex-direction: row;
    gap: 8px;
    overflow-x: auto;
    padding-bottom: 4px;
    scrollbar-width: thin;
  }
  .page-about .about-index__list > li {
    flex: 0 0 auto;
  }
  .page-about .about-index__link {
    white-space: nowrap;
    border-left: 0;
    border-bottom: 2px solid transparent;
    border-radius: 999px;
    background: var(--ocean-050);
  }
  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    border-bottom-color: var(--coral-500);
    border-left-color: transparent;
  }
}

/* ---------- 正文列 ---------- */
.page-about .about-body {
  display: flex;
  flex-direction: column;
  gap: clamp(42px, 6vw, 84px);
  min-width: 0;
}

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

.page-about .about-chapter__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding-top: 12px;
  border-top: 2px solid var(--ocean-600);
  margin-bottom: 18px;
}

.page-about .about-chapter__num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: var(--step-2);
  letter-spacing: -0.03em;
  color: var(--coral-600);
  font-variant-numeric: tabular-nums;
}

.page-about .about-chapter__title {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 800;
  font-size: var(--step-3);
  line-height: 1.22;
  letter-spacing: -0.02em;
  color: var(--ink-900);
}

.page-about .about-prose p {
  margin: 0 0 1em;
  max-width: 68ch;
  font-size: var(--step-0);
  line-height: 1.78;
  color: var(--ink-soft);
}

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

.page-about .about-chapter__split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
}

@media (min-width: 760px) {
  .page-about .about-chapter__split {
    grid-template-columns: minmax(0, 1fr) minmax(190px, 280px);
    gap: clamp(22px, 3vw, 42px);
    align-items: start;
  }
}

.page-about .about-chapter__fig {
  margin: 0;
}

.page-about .about-chapter__fig .wh-figure__img,
.page-about .about-cover__fig .wh-figure__img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  object-fit: cover;
  box-shadow: var(--shadow-soft);
}

.page-about .about-chapter__fig .wh-figure__cap,
.page-about .about-cover__fig .wh-figure__cap {
  margin-top: 10px;
  font-size: var(--step--1);
  line-height: 1.55;
  color: var(--ink-soft);
}

/* ---------- 五步流程 ---------- */
.page-about .about-stepbar {
  display: block;
  width: 100%;
  height: 8px;
  margin: 4px 0 18px;
  color: rgba(14, 92, 124, 0.32);
}

.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 12px;
}

.page-about .about-steps__item {
  padding: 14px 14px 16px;
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  background: #fff;
}

.page-about .about-steps__num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  margin-bottom: 10px;
  border-radius: 50%;
  background: var(--ocean-600);
  color: #fff;
  font-family: var(--font-mono);
  font-size: var(--step--1);
  font-weight: 700;
}

.page-about .about-steps__item h3 {
  margin: 0 0 6px;
  font-family: var(--font-narrow);
  font-weight: 700;
  font-size: var(--step-1);
  letter-spacing: 0.01em;
  color: var(--ink-900);
}

.page-about .about-steps__item p {
  margin: 0;
  font-size: var(--step--1);
  line-height: 1.7;
  color: var(--ink-soft);
}

/* ---------- 折叠内容组 ---------- */
.page-about .about-folds {
  display: grid;
  gap: 10px;
  margin-top: 18px;
}

.page-about .about-fold {
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  background: #fff;
  overflow: hidden;
}

.page-about .about-fold__trigger {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  border: 0;
  background: none;
  font: inherit;
  color: inherit;
  text-align: left;
  cursor: pointer;
  transition: background var(--speed) ease;
}

.page-about .about-fold__trigger:hover {
  background: var(--ocean-050);
}

.page-about .about-fold__trigger:focus-visible {
  outline: 2px solid var(--coral-500);
  outline-offset: -3px;
}

.page-about .about-fold__label {
  flex: 1 1 auto;
  font-family: var(--font-narrow);
  font-weight: 700;
  font-size: var(--step-1);
  color: inherit;
}

.page-about .about-fold__mark {
  flex: 0 0 auto;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--ocean-050);
  color: var(--ocean-600);
  font-family: var(--font-narrow);
  font-size: var(--step--1);
  letter-spacing: 0.06em;
}

.page-about .about-fold__year {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: var(--step-1);
  font-variant-numeric: tabular-nums;
  color: var(--coral-500);
}

.page-about .about-fold__chev {
  flex: 0 0 auto;
  width: 10px;
  height: 10px;
  margin-right: 4px;
  border-right: 2px solid var(--ink-soft);
  border-bottom: 2px solid var(--ink-soft);
  transform: rotate(45deg) translate(-2px, -2px);
  transition: transform var(--speed) ease;
}

.page-about .about-fold[data-open] .about-fold__chev {
  transform: rotate(225deg) translate(-2px, -2px);
}

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

.page-about .about-fold__panel p {
  margin: 0;
  font-size: var(--step-0);
  line-height: 1.75;
  color: var(--ink-soft);
}

.page-about .about-callout {
  margin: 18px 0 0;
  padding: 16px 18px;
  border-left: 4px solid var(--coral-500);
  border-radius: var(--radius);
  background: var(--coral-050);
  font-size: var(--step-0);
  line-height: 1.75;
  color: var(--ink-900);
}

/* ---------- 数据明细表 ---------- */
.page-about .about-metric {
  margin-top: 20px;
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  overflow: hidden;
  background: #fff;
}

.page-about .about-metric__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
  padding: 12px 16px;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-metric__row:nth-child(odd) {
  background: var(--ocean-050);
}

.page-about .about-metric__row:last-child {
  border-bottom: 0;
}

@media (min-width: 560px) {
  .page-about .about-metric__row {
    grid-template-columns: 148px minmax(0, 1fr);
    gap: 18px;
    align-items: baseline;
  }
}

.page-about .about-metric__k {
  font-family: var(--font-narrow);
  font-weight: 700;
  font-size: var(--step--1);
  letter-spacing: 0.08em;
  color: var(--ocean-600);
}

.page-about .about-metric__v {
  font-size: var(--step-0);
  line-height: 1.65;
  color: var(--ink-900);
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: 20px;
}

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

.page-about .about-team__card {
  padding: 20px;
  border-radius: var(--radius);
  background: var(--ocean-900);
  color: #fff;
}

.page-about .about-team__card:nth-child(2) {
  background: var(--ocean-600);
}

.page-about .about-team__n {
  display: block;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  font-size: var(--step-4);
  font-weight: 700;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  color: var(--coral-500);
}

.page-about .about-team__card h3 {
  margin: 0 0 8px;
  font-family: var(--font-narrow);
  font-weight: 700;
  font-size: var(--step-1);
  color: #fff;
}

.page-about .about-team__card p {
  margin: 0;
  font-size: var(--step--1);
  line-height: 1.75;
  color: rgba(255, 255, 255, 0.78);
}

/* ---------- 覆盖面 ---------- */
.page-about .about-cover__fig {
  margin: 0 0 20px;
}

.page-about .about-cover__text p {
  max-width: 66ch;
}

.page-about .about-cover__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 20px;
}

@media (min-width: 720px) {
  .page-about .about-cover__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .about-cover__stat {
  padding: 14px;
  border: 1px solid var(--about-rule);
  border-top: 3px solid var(--grass-500);
  border-radius: var(--radius);
  background: #fff;
}

.page-about .about-cover__stat span {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--step-2);
  font-weight: 700;
  line-height: 1.1;
  font-variant-numeric: tabular-nums;
  color: var(--ocean-700);
}

.page-about .about-cover__stat em {
  display: block;
  margin-top: 6px;
  font-style: normal;
  font-size: var(--step--1);
  line-height: 1.5;
  color: var(--ink-soft);
}

/* ---------- 版本年表 ---------- */
.page-about .about-timeline {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  border-radius: var(--radius-lg);
  background: var(--ocean-950);
  padding: clamp(22px, 4vw, 46px);
  color: #fff;
}

.page-about .about-timeline__bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.34;
}

.page-about .about-timeline::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background: linear-gradient(158deg, rgba(4, 22, 31, 0.9) 0%, rgba(8, 42, 59, 0.84) 100%);
}

.page-about .about-timeline__inner {
  position: relative;
  z-index: 2;
}

.page-about .about-timeline__title {
  margin: 0 0 18px;
  font-family: var(--font-serif);
  font-weight: 800;
  font-size: var(--step-2);
  letter-spacing: -0.01em;
  color: #fff;
}

.page-about .about-timeline .about-folds {
  margin-top: 0;
}

.page-about .about-timeline .about-fold {
  background: rgba(255, 255, 255, 0.06);
  border-color: rgba(255, 255, 255, 0.16);
  color: #fff;
}

.page-about .about-timeline .about-fold__trigger {
  color: #fff;
}

.page-about .about-timeline .about-fold__trigger:hover {
  background: rgba(255, 255, 255, 0.1);
}

.page-about .about-timeline .about-fold__trigger:focus-visible {
  outline-color: var(--ocean-300);
}

.page-about .about-timeline .about-fold__chev {
  border-right-color: rgba(255, 255, 255, 0.65);
  border-bottom-color: rgba(255, 255, 255, 0.65);
}

.page-about .about-timeline .about-fold__panel p {
  color: rgba(255, 255, 255, 0.8);
}

/* ---------- 互校合作 ---------- */
.page-about .about-partners {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin-top: 20px;
}

@media (min-width: 700px) {
  .page-about .about-partners {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.page-about .about-partners__item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 18px;
  border-left: 4px solid var(--coral-500);
  border-radius: var(--radius);
  background: var(--ocean-050);
}

.page-about .about-partners__n {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--step-4);
  font-weight: 700;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  color: var(--coral-600);
}

.page-about .about-partners__item p {
  margin: 0;
  font-size: var(--step--1);
  line-height: 1.75;
  color: var(--ink-soft);
}

/* ---------- 延伸入口 ---------- */
.page-about .about-next {
  padding-top: clamp(24px, 3.5vw, 40px);
  border-top: 2px solid var(--ink-900);
}

.page-about .about-next__title {
  margin: 0 0 18px;
  font-family: var(--font-serif);
  font-weight: 800;
  font-size: var(--step-2);
  letter-spacing: -0.01em;
  color: var(--ink-900);
}

.page-about .about-next__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 12px;
}

.page-about .about-next__link {
  display: flex;
  flex-direction: column;
  gap: 8px;
  height: 100%;
  padding: 16px 16px 18px;
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  background: #fff;
  text-decoration: none;
  transition: transform var(--speed) ease, border-color var(--speed) ease, box-shadow var(--speed) ease;
}

.page-about .about-next__link:hover,
.page-about .about-next__link:focus-visible {
  transform: translateY(-4px);
  border-color: var(--ocean-600);
  box-shadow: var(--shadow-soft);
}

.page-about .about-next__name {
  font-family: var(--font-narrow);
  font-weight: 700;
  font-size: var(--step-1);
  color: var(--ocean-600);
}

.page-about .about-next__link em {
  font-style: normal;
  font-size: var(--step--1);
  line-height: 1.6;
  color: var(--ink-soft);
}

/* ---------- 动效 ---------- */
@media (prefers-reduced-motion: no-preference) {
  .page-about [data-reveal].is-visible {
    animation: about-rise 0.5s ease both;
  }
}

@keyframes about-rise {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-next__link,
  .page-about .about-fold__chev,
  .page-about .about-index__link {
    transition: none;
  }
  .page-about .about-next__link:hover,
  .page-about .about-next__link:focus-visible {
    transform: none;
  }
}