/* ==========================================================
   红海档案 · 研究板式双栏
   作用域：.page-about
   ========================================================== */

.page-about {
  --about-idx: 14rem;
  background: var(--pearl);
  color: var(--ink);
}

/* ---------- 首屏：深海长图 + 压图文字 ---------- */

.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  background: var(--abyss);
  color: var(--on-dark);
}

.page-about .about-hero__media {
  position: absolute;
  inset: 0;
  z-index: 0;
  margin: 0;
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: .58;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background: linear-gradient(
    180deg,
    rgba(6, 26, 46, .9) 0%,
    rgba(11, 46, 79, .5) 46%,
    rgba(6, 26, 46, .97) 100%
  );
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 2;
  padding: clamp(2.25rem, 7vw, 4.5rem) 0 clamp(2.5rem, 8vw, 5.5rem);
}

.page-about .about-hero .breadcrumb {
  font-family: var(--mono);
  font-size: var(--fz-13);
  letter-spacing: .1em;
}

.page-about .about-hero .breadcrumb a,
.page-about .about-hero .breadcrumb li {
  color: var(--on-dark-dim);
}

.page-about .about-hero .breadcrumb [aria-current="page"] {
  color: var(--amber);
}

.page-about .about-hero__title {
  margin: 1.1rem 0 .85rem;
  font-size: var(--fz-40);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -.012em;
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 40ch;
  font-size: var(--fz-17);
  line-height: 1.85;
  color: var(--on-dark);
}

.page-about .about-hero__meta {
  margin: 1.75rem 0 0;
  padding-top: .9rem;
  font-size: var(--fz-13);
  letter-spacing: .18em;
  color: var(--on-dark-dim);
  border-top: 1px solid rgba(246, 243, 238, .2);
}

/* ---------- 板面骨架 ---------- */

.page-about .about-board {
  padding: clamp(2rem, 6vw, 3.75rem) 0 clamp(3rem, 9vw, 6rem);
}

/* ---------- 左栏编号索引 ---------- */

.page-about .about-index {
  margin: 0 0 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--line);
}

.page-about .about-index__label {
  margin: 0 0 .65rem;
  font-size: var(--fz-13);
  letter-spacing: .24em;
  color: var(--mist);
}

.page-about .about-index__list {
  display: flex;
  gap: .5rem;
  margin: 0;
  padding: 0 0 .35rem;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-index__link {
  display: inline-flex;
  align-items: baseline;
  gap: .45rem;
  padding: .35rem .7rem;
  white-space: nowrap;
  font-size: var(--fz-15);
  color: var(--ink);
  text-decoration: none;
  background: var(--cream);
  border: 1px solid var(--line);
  transition: color .18s var(--ease), background .18s var(--ease), border-color .18s var(--ease);
}

.page-about .about-index__no {
  font-size: var(--fz-13);
  color: var(--mist);
  transition: color .18s var(--ease);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--amber);
  background: var(--deep-sea);
  border-color: var(--amber);
}

.page-about .about-index__link:hover .about-index__no,
.page-about .about-index__link:focus-visible .about-index__no {
  color: var(--amber);
}

/* ---------- 章节通用 ---------- */

.page-about .about-section {
  margin: 0 0 clamp(2.75rem, 8vw, 5.5rem);
  scroll-margin-top: 1.5rem;
}

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

.page-about .about-section__no {
  margin: 0 0 .35rem;
  font-size: var(--fz-13);
  font-weight: 700;
  letter-spacing: .32em;
  color: var(--coral);
}

.page-about .about-section__title {
  margin: 0 0 .65rem;
  font-size: var(--fz-28);
  font-weight: 900;
  line-height: 1.18;
  letter-spacing: -.008em;
}

.page-about .about-section__lead {
  margin: 0 0 1.75rem;
  max-width: 38ch;
  font-size: var(--fz-17);
  line-height: 1.85;
  color: var(--mist);
}

.page-about .about-p {
  margin: 0 0 1rem;
  max-width: 38ch;
  font-size: var(--fz-17);
  line-height: 1.85;
}

/* ---------- 01 档案摘要 ---------- */

.page-about .about-summary {
  background: var(--cream);
  border: 1px solid var(--line);
  border-top: 3px solid var(--coral);
  padding: clamp(1rem, 3.2vw, 1.5rem) clamp(1.05rem, 3.6vw, 2.25rem);
}

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

.page-about .about-facts__item {
  display: grid;
  gap: .3rem;
  padding: 1.05rem 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-facts__item:first-child {
  padding-top: .35rem;
}

.page-about .about-facts__item:last-child {
  padding-bottom: .35rem;
  border-bottom: 0;
}

.page-about .about-facts__k {
  font-size: var(--fz-13);
  letter-spacing: .18em;
  color: var(--mist);
}

.page-about .about-facts__v {
  font-size: var(--fz-17);
  line-height: 1.8;
}

.page-about .about-facts__v a {
  color: var(--coral);
  font-weight: 700;
  text-decoration: none;
  border-bottom: 2px solid var(--coral);
}

/* ---------- 02 沿革时间线 ---------- */

.page-about .about-timeline {
  position: relative;
  margin: 0;
  padding: 0 0 0 1.9rem;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: .55rem;
  bottom: 1.4rem;
  width: 1px;
  background: var(--line);
}

.page-about .about-timeline__item {
  position: relative;
  padding: 0 0 1.9rem 1.4rem;
}

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

.page-about .about-timeline__node {
  position: absolute;
  left: -1.9rem;
  top: .08rem;
  display: inline-block;
  padding: .17rem .55rem;
  font-family: var(--mono);
  font-size: var(--fz-13);
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--abyss);
  background: var(--amber);
  transform: skewX(-12deg);
  transition: background .2s var(--ease), color .2s var(--ease);
}

.page-about .about-timeline__node > span {
  display: inline-block;
  transform: skewX(12deg);
}

.page-about .about-timeline__item#tl-32 .about-timeline__node,
.page-about .about-timeline__item:target .about-timeline__node {
  background: var(--coral);
  color: var(--pearl);
}

.page-about .about-timeline__title {
  margin: 0 0 .35rem;
  font-size: var(--fz-20);
  font-weight: 800;
  line-height: 1.35;
}

.page-about .about-timeline__text {
  margin: 0;
  max-width: 38ch;
  font-size: var(--fz-17);
  line-height: 1.85;
}

/* ---------- 03 栏目体系图谱 ---------- */

.page-about .about-map {
  display: grid;
  gap: clamp(1.5rem, 3.6vw, 2.25rem);
  margin: 0 0 clamp(1.75rem, 4vw, 2.5rem);
}

.page-about .about-map__group {
  display: flex;
  flex-direction: column;
  gap: .6rem;
}

.page-about .about-map__gtitle {
  margin: 0 0 .35rem;
  padding-bottom: .5rem;
  font-size: var(--fz-13);
  letter-spacing: .2em;
  color: var(--deep-sea);
  border-bottom: 2px solid var(--tide);
}

.page-about .about-map__group:nth-child(2) .about-map__gtitle {
  border-bottom-color: var(--coral);
}

.page-about .about-map__group:nth-child(3) .about-map__gtitle {
  border-bottom-color: var(--gold);
}

.page-about .about-node {
  padding: .8rem .9rem .9rem 1rem;
  background: var(--cream);
  border-left: 3px solid var(--tide);
}

.page-about .about-map__group:nth-child(2) .about-node {
  border-left-color: var(--coral);
}

.page-about .about-map__group:nth-child(3) .about-node {
  border-left-color: var(--gold);
}

.page-about .about-node__head {
  display: flex;
  align-items: baseline;
  gap: .5rem;
  margin: 0 0 .3rem;
}

.page-about .about-node__no {
  font-size: var(--fz-13);
  color: var(--mist);
}

.page-about .about-node__name {
  font-size: var(--fz-18);
  font-weight: 800;
}

.page-about .about-node__desc {
  margin: 0 0 .5rem;
  font-size: var(--fz-15);
  line-height: 1.75;
}

.page-about .about-node__count {
  margin: 0;
  font-size: var(--fz-13);
  letter-spacing: .1em;
  color: var(--mist);
}

/* ---------- 通用图注 ---------- */

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

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  background: var(--cream);
}

.page-about .about-figure figcaption {
  margin-top: .6rem;
  font-size: var(--fz-13);
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 04 维护小组与分工 ---------- */

.page-about .about-team {
  display: grid;
  gap: 1px;
  margin: 0 0 1.75rem;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .about-role {
  padding: 1.25rem 1.15rem 1.4rem;
  background: var(--cream);
}

.page-about .about-role__n {
  margin: 0 0 .4rem;
  font-size: var(--fz-40);
  font-weight: 700;
  line-height: 1;
  color: var(--deep-sea);
}

.page-about .about-role__title {
  margin: 0 0 .5rem;
  font-size: var(--fz-18);
  font-weight: 800;
}

.page-about .about-role p {
  margin: 0;
  font-size: var(--fz-15);
  line-height: 1.8;
}

.page-about .about-cadence {
  margin: 0 0 1.75rem;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-cadence__row {
  padding: .9rem 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-cadence__row dt {
  margin: 0 0 .3rem;
  font-size: var(--fz-13);
  letter-spacing: .18em;
  color: var(--coral);
}

.page-about .about-cadence__row dd {
  margin: 0;
  font-size: var(--fz-15);
  line-height: 1.8;
}

/* ---------- 05 证据边界 ---------- */

.page-about .about-boundary {
  display: grid;
  gap: 1.5rem;
  padding: clamp(1.5rem, 4vw, 2.5rem);
  background: var(--deep-sea);
  color: var(--on-dark);
}

.page-about .about-boundary__col h3 {
  margin: 0 0 .6rem;
  font-size: var(--fz-18);
  font-weight: 800;
  color: var(--pearl);
}

.page-about .about-boundary__col h3::before {
  content: "";
  display: block;
  width: 2rem;
  height: 3px;
  margin-bottom: .7rem;
  background: var(--amber);
}

.page-about .about-boundary__col p {
  margin: 0;
  max-width: 40ch;
  font-size: var(--fz-15);
  line-height: 1.85;
  color: var(--on-dark);
}

/* ---------- 06 延伸阅读 ---------- */

.page-about .about-links {
  margin: 0 0 1.75rem;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .about-link {
  display: block;
  padding: 1rem .25rem;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  transition: transform .18s var(--ease), color .18s var(--ease);
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  transform: translateX(2px);
  color: var(--coral);
}

.page-about .about-link__top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
}

.page-about .about-link__name {
  font-size: var(--fz-18);
  font-weight: 800;
}

.page-about .about-link__no {
  font-size: var(--fz-13);
  color: var(--mist);
}

.page-about .about-link__desc {
  display: block;
  margin-top: .25rem;
  max-width: 40ch;
  font-size: var(--fz-15);
  line-height: 1.75;
  color: var(--mist);
}

.page-about .about-devices {
  display: grid;
  gap: 1.1rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
}

.page-about .about-device h3 {
  margin: 0 0 .4rem;
  font-size: var(--fz-15);
  font-weight: 800;
  color: var(--deep-sea);
}

.page-about .about-device p {
  margin: 0;
  font-size: var(--fz-15);
  line-height: 1.8;
}

/* ==========================================================
   断点
   ========================================================== */

@media (min-width: 640px) {
  .page-about .about-facts__item {
    grid-template-columns: 7.5rem minmax(0, 1fr);
    gap: 1.5rem;
    align-items: baseline;
  }
}

@media (min-width: 720px) {
  .page-about .about-team {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-cadence {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0 1.75rem;
    border-bottom: 1px solid var(--line);
  }

  .page-about .about-cadence__row {
    border-bottom: 0;
  }

  .page-about .about-devices {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 2rem;
  }
}

@media (min-width: 760px) {
  .page-about .about-map {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-boundary {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 2.25rem 3rem;
  }

  .page-about .about-boundary__col--wide {
    grid-column: 1 / -1;
    padding-top: 1.4rem;
    border-top: 1px solid rgba(246, 243, 238, .22);
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__title {
    font-size: var(--fz-72);
  }

  .page-about .about-hero__lede {
    font-size: var(--fz-18);
  }

  .page-about .about-section__title {
    font-size: var(--fz-40);
  }

  .page-about .about-section__lead {
    font-size: var(--fz-18);
  }

  .page-about .about-p,
  .page-about .about-timeline__text {
    font-size: var(--fz-18);
  }

  .page-about .about-board {
    display: grid;
    grid-template-columns: var(--about-idx) minmax(0, 1fr);
    gap: clamp(2rem, 5vw, 4.5rem);
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: 1.75rem;
    margin: 0;
    padding: 0 0 0 1.1rem;
    border-bottom: 0;
    border-left: 1px solid var(--line);
  }

  .page-about .about-index__list {
    display: block;
    overflow: visible;
    padding: 0;
  }

  .page-about .about-index__list > li + li {
    margin-top: .55rem;
  }

  .page-about .about-index__link {
    display: flex;
    gap: .55rem;
    width: 100%;
    padding: .15rem 0;
    white-space: normal;
    background: none;
    border: 0;
  }

  .page-about .about-index__link:hover,
  .page-about .about-index__link:focus-visible {
    background: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__link,
  .page-about .about-link,
  .page-about .about-timeline__node {
    transition: none;
  }

  .page-about .about-link:hover,
  .page-about .about-link:focus-visible {
    transform: none;
  }
}
<<<END>>>