.page-about {
  --rail: 236px;
  --role-bg: linear-gradient(158deg, rgba(20, 28, 63, 0.88) 0%, rgba(6, 23, 38, 0.72) 100%);
  --panel-bg: linear-gradient(168deg, rgba(12, 46, 58, 0.82) 0%, rgba(6, 23, 38, 0.94) 100%);
  --body-text: #BFD0DA;
  background: var(--ink);
  color: var(--porcelain);
  overflow-x: clip;
}

.page-about a {
  color: inherit;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: calc(var(--header-h) + clamp(48px, 7vw, 88px)) 0 clamp(40px, 6vw, 76px);
  background:
    radial-gradient(118% 86% at 82% 0%, rgba(37, 242, 214, 0.13) 0%, rgba(37, 242, 214, 0) 58%),
    radial-gradient(90% 70% at 4% 100%, rgba(74, 16, 48, 0.5) 0%, rgba(74, 16, 48, 0) 62%),
    linear-gradient(180deg, #07202F 0%, var(--ink) 76%);
  border-bottom: 1px solid var(--line);
  overflow: hidden;
}

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

.page-about .about-hero .breadcrumbs {
  margin-bottom: clamp(20px, 3vw, 32px);
}

.page-about .about-hero .eyebrow {
  margin: 0 0 18px;
}

.page-about .about-hero__title {
  margin: 0;
  max-width: 15em;
  font-size: clamp(34px, 6.4vw, 74px);
  line-height: 1.14;
  font-weight: 900;
  letter-spacing: -0.025em;
}

.page-about .about-hero__accent {
  color: var(--cyan);
}

.page-about .about-hero__lead {
  margin: clamp(22px, 3.4vw, 34px) 0 0;
  max-width: 42em;
  font-size: clamp(15.5px, 1.6vw, 18px);
  line-height: 1.85;
  color: var(--body-text);
}

.page-about .hero-facts {
  list-style: none;
  margin: clamp(30px, 4.4vw, 50px) 0 0;
  padding: 24px 0 0;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 18px;
  max-width: 700px;
}

.page-about .hero-fact__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(24px, 3.4vw, 34px);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--cyan);
}

.page-about .hero-fact__unit {
  margin-left: 3px;
  font-size: 12px;
  font-weight: 400;
  letter-spacing: 0.06em;
  color: var(--mist);
}

.page-about .hero-fact__label {
  display: block;
  margin-top: 8px;
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: var(--mist);
}

.page-about .about-hero__mark {
  position: absolute;
  right: clamp(10px, 2.6vw, 42px);
  top: 46%;
  transform: translateY(-50%);
  writing-mode: vertical-rl;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.34em;
  color: var(--mist);
  opacity: 0.62;
  pointer-events: none;
  user-select: none;
}

/* ---------- 档案布局 ---------- */
.page-about .archive {
  max-width: var(--shell);
  margin: 0 auto;
  padding: clamp(40px, 6vw, 76px) var(--gutter) clamp(64px, 9vw, 128px);
}

.page-about .archive-rail {
  margin-bottom: 34px;
}

.page-about .rail-label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.24em;
  color: var(--mist);
}

.page-about .rail-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px 14px;
}

.page-about .rail-link {
  display: flex;
  align-items: baseline;
  gap: 9px;
  padding: 7px 4px 7px 12px;
  border-left: 2px solid transparent;
  text-decoration: none;
  font-size: 13px;
  line-height: 1.5;
  color: var(--mist);
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease), background-color 0.2s var(--ease);
}

.page-about .rail-link:hover,
.page-about .rail-link:focus-visible {
  color: var(--porcelain);
  border-left-color: var(--cyan);
  background: rgba(37, 242, 214, 0.06);
}

.page-about .rail-num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.1em;
  color: var(--amber);
}

.page-about .rail-note {
  margin: 16px 0 0;
  padding-left: 12px;
  font-size: 11.5px;
  line-height: 1.7;
  color: var(--mist);
  letter-spacing: 0.04em;
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-sec {
  padding-block: clamp(38px, 5.6vw, 72px);
  border-top: 1px solid var(--line-soft);
}

.page-about .ab-sec:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .ab-sec--teal {
  background: linear-gradient(170deg, rgba(12, 46, 58, 0.62) 0%, rgba(6, 23, 38, 0) 78%);
  border-radius: var(--r-xl);
  padding-inline: clamp(18px, 3vw, 34px);
  margin-inline: calc(-1 * clamp(0px, 1vw, 0px));
}

.page-about .ab-sec__head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: clamp(18px, 2.4vw, 26px);
}

.page-about .ab-sec__num {
  flex: none;
  padding-top: 4px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.18em;
  color: var(--amber);
}

.page-about .ab-sec__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 3.6vw, 38px);
  line-height: 1.24;
  letter-spacing: -0.022em;
  color: var(--porcelain);
}

.page-about .ab-prose {
  margin: 0 0 16px;
  max-width: var(--measure);
  font-size: 16px;
  line-height: 1.85;
  color: var(--body-text);
}

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

/* ---------- 双栏区块 ---------- */
.page-about .ab-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 3.6vw, 40px);
  align-items: start;
}

/* ---------- 职能卡片 ---------- */
.page-about .role-grid {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.page-about .role-card {
  position: relative;
  padding: 20px 20px 22px;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--role-bg);
  transition: border-color 0.24s var(--ease), transform 0.24s var(--ease);
}

.page-about .role-card::before {
  content: "";
  position: absolute;
  left: 20px;
  top: 0;
  width: 34px;
  height: 2px;
  background: var(--cyan);
  border-radius: var(--r-pill);
}

.page-about .role-card:hover {
  border-color: var(--line-cyan);
  transform: translateY(-3px);
}

.page-about .role-name {
  margin: 8px 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16.5px;
  letter-spacing: -0.01em;
  color: var(--porcelain);
}

.page-about .role-text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--body-text);
}

/* ---------- 图片框 ---------- */
.page-about .ab-figure {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  overflow: hidden;
  background: linear-gradient(160deg, rgba(20, 28, 63, 0.85) 0%, rgba(12, 46, 58, 0.6) 100%);
}

.page-about .ab-figure--wide {
  margin-top: clamp(26px, 3.6vw, 40px);
}

.page-about .ab-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .ab-figure figcaption {
  padding: 13px 20px 16px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.65;
  letter-spacing: 0.05em;
  color: var(--mist);
}

/* ---------- 分段切换 ---------- */
.page-about .ch-tabs {
  margin-top: clamp(22px, 3vw, 32px);
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  background: var(--panel-bg);
  overflow: hidden;
}

.page-about .ch-tablist {
  display: flex;
  gap: 8px;
  padding: 12px;
  border-bottom: 1px solid var(--line-soft);
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .ch-tablist::-webkit-scrollbar {
  display: none;
}

.page-about .ch-tab {
  flex: none;
  appearance: none;
  border: 1px solid transparent;
  border-radius: var(--r-pill);
  padding: 10px 20px;
  background: rgba(20, 28, 63, 0.72);
  color: var(--mist);
  font-family: var(--font-body);
  font-size: 13.5px;
  font-weight: 500;
  line-height: 1.2;
  white-space: nowrap;
  cursor: pointer;
  transition: color 0.2s var(--ease), background-color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .ch-tab:hover {
  color: var(--porcelain);
  border-color: var(--line-cyan);
}

.page-about .ch-tab[aria-selected="true"] {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink);
  font-weight: 700;
}

.page-about .ch-tab:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .ch-panel {
  padding: clamp(22px, 3vw, 34px);
}

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

.page-about .ch-panel__label {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--cyan);
}

.page-about .ch-panel__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(19px, 2.4vw, 24px);
  letter-spacing: -0.015em;
  color: var(--porcelain);
}

.page-about .ch-panel__text {
  margin: 0;
  max-width: var(--measure);
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--body-text);
}

.page-about .ch-points {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .ch-points li {
  position: relative;
  padding-left: 22px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .ch-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 12px;
  height: 1px;
  background: var(--orange);
}

/* ---------- 版本时间线 ---------- */
.page-about .ver-list {
  --mark: 40px;
  list-style: none;
  position: relative;
  margin: clamp(26px, 3.6vw, 38px) 0 0;
  padding: 0;
}

.page-about .ver-list::before {
  content: "";
  position: absolute;
  left: calc(var(--mark) / 2);
  top: 6px;
  bottom: 6px;
  width: 1px;
  background: linear-gradient(180deg, var(--line-cyan) 0%, var(--line-soft) 100%);
}

.page-about .ver-item {
  position: relative;
  padding-left: calc(var(--mark) + 18px);
  padding-bottom: 30px;
}

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

.page-about .ver-mark {
  position: absolute;
  left: 0;
  top: 0;
  box-sizing: border-box;
  width: var(--mark);
  height: var(--mark);
  display: grid;
  place-items: center;
  border-radius: var(--r-pill);
  background: var(--cyan);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.page-about .ver-item--now .ver-mark {
  background: var(--orange);
  box-shadow: 0 0 0 6px rgba(255, 138, 61, 0.14);
}

.page-about .ver-phase {
  margin: 4px 0 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .ver-title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18.5px;
  line-height: 1.35;
  letter-spacing: -0.012em;
  color: var(--porcelain);
}

.page-about .ver-text {
  margin: 0;
  max-width: var(--measure);
  font-size: 15px;
  line-height: 1.82;
  color: var(--body-text);
}

/* ---------- 合作示意 ---------- */
.page-about .coop-map {
  display: block;
  width: 100%;
  max-width: 520px;
  height: auto;
  margin: clamp(24px, 3.4vw, 36px) auto 0;
  border: 1px solid var(--line);
  border-radius: var(--r-xl);
  background: linear-gradient(160deg, rgba(12, 46, 58, 0.7) 0%, rgba(6, 23, 38, 0.95) 100%);
}

.page-about .cm-link {
  stroke: rgba(37, 242, 214, 0.42);
  stroke-width: 1.4;
  stroke-dasharray: 5 6;
  fill: none;
}

.page-about .cm-node {
  fill: rgba(20, 28, 63, 0.94);
  stroke: rgba(37, 242, 214, 0.7);
  stroke-width: 1.3;
}

.page-about .cm-node--core {
  fill: rgba(37, 242, 214, 0.12);
  stroke: var(--cyan);
  stroke-width: 2;
}

.page-about .cm-label {
  fill: var(--mist);
  font-family: var(--font-body);
  font-size: 17px;
}

.page-about .cm-core {
  fill: var(--cyan);
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 800;
}

.page-about .coop-list {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.page-about .coop-item {
  padding: 20px 20px 22px;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: rgba(20, 28, 63, 0.5);
}

.page-about .coop-name {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16px;
  letter-spacing: -0.01em;
  color: var(--cyan);
}

.page-about .coop-text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--body-text);
}

/* ---------- 巡检清单 ---------- */
.page-about .check-list {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .check-item {
  display: grid;
  grid-template-columns: 14px minmax(0, 1fr);
  gap: 14px;
  align-items: start;
}

.page-about .check-dot {
  width: 12px;
  height: 12px;
  margin-top: 6px;
  border-radius: var(--r-pill);
  background: var(--cyan);
  box-shadow: 0 0 0 4px rgba(37, 242, 214, 0.14);
}

.page-about .check-item:last-child .check-dot {
  background: var(--signal);
  box-shadow: 0 0 0 4px rgba(76, 217, 123, 0.14);
}

.page-about .check-name {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16px;
  letter-spacing: -0.01em;
  color: var(--porcelain);
}

.page-about .check-text {
  margin: 0;
  max-width: var(--measure);
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--body-text);
}

/* ---------- 侧栏入口 ---------- */
.page-about .ab-aside {
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: linear-gradient(165deg, rgba(74, 16, 48, 0.62) 0%, rgba(6, 23, 38, 0.9) 100%);
  padding: 22px 22px 24px;
}

.page-about .ab-aside__title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--amber);
}

.page-about .ab-aside__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .ab-aside__link {
  display: block;
  padding: 10px 0;
  border-bottom: 1px solid var(--line-soft);
  font-size: 14.5px;
  line-height: 1.6;
  text-decoration: none;
  color: var(--porcelain);
  transition: color 0.2s var(--ease), padding-left 0.2s var(--ease);
}

.page-about .ab-aside__list li:last-child .ab-aside__link {
  border-bottom: 0;
}

.page-about .ab-aside__link:hover,
.page-about .ab-aside__link:focus-visible {
  color: var(--cyan);
  padding-left: 6px;
}

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

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

@media (min-width: 760px) {
  .page-about .hero-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .ab-split {
    grid-template-columns: minmax(0, 1.32fr) minmax(0, 1fr);
    gap: clamp(32px, 4vw, 56px);
  }

  .page-about .ab-split--reverse {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.32fr);
  }

  .page-about .ab-split--reverse .ab-figure {
    order: -1;
  }
}

@media (min-width: 1000px) {
  .page-about .archive {
    display: grid;
    grid-template-columns: var(--rail) minmax(0, 1fr);
    column-gap: clamp(38px, 4.4vw, 76px);
    align-items: start;
  }

  .page-about .archive-rail {
    margin-bottom: 0;
  }

  .page-about .archive-rail__inner {
    position: sticky;
    top: calc(var(--header-h) + 44px);
    padding-right: 22px;
  }

  .page-about .archive-rail__inner::after {
    content: "";
    position: absolute;
    right: 0;
    top: 4px;
    bottom: 8px;
    width: 1px;
    background: linear-gradient(180deg, var(--line-cyan) 0%, rgba(155, 179, 192, 0.05) 88%);
  }

  .page-about .rail-list {
    grid-template-columns: 1fr;
    gap: 1px;
  }

  .page-about .ver-list {
    --mark: 48px;
  }
}

@media (min-width: 1180px) {
  .page-about .ab-split {
    grid-template-columns: minmax(0, 1.42fr) minmax(0, 1fr);
  }

  .page-about .ab-split--reverse {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.42fr);
  }
}

@media (max-width: 900px) {
  .page-about .about-hero__mark {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .role-card,
  .page-about .ch-tab,
  .page-about .rail-link,
  .page-about .ab-aside__link {
    transition: none;
  }

  .page-about .role-card:hover {
    transform: none;
  }
}