.page-about {
  --about-rail: 216px;
  --about-gap: 56px;
  --about-grid: rgba(30, 53, 96, 0.42);
}

/* —— 面包屑 —— */
.page-about .breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  padding-top: 20px;
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  color: var(--text-dim);
}

.page-about .breadcrumb a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s var(--ease);
}

.page-about .breadcrumb a:hover {
  border-bottom-color: var(--cyan);
}

/* —— 首屏 —— */
.page-about .about-hero {
  display: grid;
  gap: 26px;
  padding: 26px 0 40px;
  border-bottom: 1px solid var(--line-soft);
}

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

.page-about .about-hero__main h1 {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(2.1rem, 7.4vw, 3.6rem);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--text);
  max-width: 20ch;
  overflow-wrap: break-word;
}

.page-about .about-hero .lede {
  margin: 20px 0 0;
  max-width: 60ch;
  font-size: 1.02rem;
  line-height: 1.9;
  color: var(--text-dim);
}

.page-about .about-hero__anchor {
  padding: 18px 20px 20px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan);
  background: linear-gradient(160deg, var(--navy-700), rgba(16, 32, 74, 0.28));
}

.page-about .about-hero__anchor-label {
  margin: 0;
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  color: var(--text-dim);
}

.page-about .about-hero__year {
  margin: 8px 0 0;
  font-family: var(--font-mono);
  font-weight: 400;
  font-size: clamp(2.8rem, 13vw, 4.4rem);
  line-height: 0.94;
  letter-spacing: -0.03em;
  color: var(--cyan);
}

.page-about .about-hero__anchor-note {
  margin: 12px 0 0;
  font-size: 0.84rem;
  line-height: 1.7;
  color: var(--text-dim);
}

/* —— 主栅格 —— */
.page-about .about-shell {
  display: grid;
  gap: 26px;
  padding: 30px 0 64px;
}

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

/* —— 左侧索引 —— */
.page-about .about-rail {
  border-top: 1px solid var(--line-soft);
  padding-top: 14px;
  min-width: 0;
}

.page-about .rail__title {
  margin: 0 0 10px;
  font-size: 0.68rem;
  letter-spacing: 0.18em;
  color: var(--text-dim);
}

.page-about .rail-nav {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 6px;
  scrollbar-width: none;
}

.page-about .rail-nav::-webkit-scrollbar {
  display: none;
}

.page-about .rail-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  flex: 0 0 auto;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 0.84rem;
  color: var(--text-dim);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease), background-color 0.16s var(--ease);
}

.page-about .rail-link__idx {
  font-size: 0.66rem;
  color: var(--cyan);
  transition: color 0.16s var(--ease);
}

.page-about .rail-link:hover {
  color: var(--text);
  border-color: var(--cyan);
}

.page-about .rail-link[aria-current="true"] {
  color: var(--navy-900);
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about .rail-link[aria-current="true"] .rail-link__idx {
  color: var(--navy-900);
}

/* —— 章节 —— */
.page-about .about-section {
  margin-top: 36px;
  padding-top: 34px;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-section:first-child {
  margin-top: 0;
  padding-top: 0;
  border-top: 0;
}

.page-about .about-section__kicker {
  margin: 0 0 10px;
  font-size: 0.7rem;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .about-section__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(1.45rem, 4.6vw, 2.1rem);
  line-height: 1.28;
  letter-spacing: -0.01em;
  color: var(--text);
  max-width: 24ch;
  overflow-wrap: break-word;
}

.page-about .prose p {
  margin: 16px 0 0;
  max-width: 66ch;
  font-size: 1rem;
  line-height: 1.9;
  color: var(--text-dim);
}

.page-about .prose p:first-child {
  margin-top: 18px;
}

/* —— 条目列表 —— */
.page-about .itemlist {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .itemlist__item {
  display: grid;
  gap: 6px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan);
  background: rgba(16, 32, 74, 0.42);
}

.page-about .itemlist__title {
  font-size: 0.98rem;
  font-weight: 500;
  color: var(--text);
}

.page-about .itemlist__text {
  margin: 0;
  font-size: 0.89rem;
  line-height: 1.78;
  color: var(--text-dim);
}

/* —— 图 —— */
.page-about .about-figure {
  margin: 26px 0 0;
  border: 1px solid var(--line);
  background: var(--navy-900);
  overflow: hidden;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  transition: transform 0.45s var(--ease);
}

.page-about .about-figure figcaption {
  padding: 10px 14px 12px;
  border-top: 1px solid var(--line-soft);
  font-size: 0.78rem;
  line-height: 1.65;
  color: var(--text-dim);
}

.page-about .about-figure:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

.page-about .about-figure:focus-visible img {
  transform: scale(1.04);
}

/* —— 数据条 —— */
.page-about .datastrip {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .datastrip__item {
  display: grid;
  gap: 5px;
  padding: 16px 18px;
  background: var(--navy-800);
}

.page-about .datastrip__num {
  font-size: 1.6rem;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--orange);
}

.page-about .datastrip__label {
  font-size: 0.82rem;
  line-height: 1.6;
  color: var(--text-dim);
}

/* —— 团队卡片 —— */
.page-about .teamgrid {
  display: grid;
  gap: 14px;
  margin: 22px 0 0;
}

.page-about .teamgrid__card {
  padding: 18px 20px 20px;
  border: 1px solid var(--line);
  border-top: 2px solid var(--cyan);
  background: var(--navy-700);
}

.page-about .teamgrid__name {
  margin: 0;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text);
}

.page-about .teamgrid__duty {
  margin: 9px 0 0;
  font-size: 0.88rem;
  line-height: 1.78;
  color: var(--text-dim);
}

/* —— 时间线 —— */
.page-about .milestones {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
}

.page-about .milestone {
  position: relative;
  padding: 0 0 20px 24px;
  border-left: 1px solid var(--line);
}

.page-about .milestone:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .milestone::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 9px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--navy-800);
  border: 2px solid var(--cyan);
  box-sizing: content-box;
}

.page-about .milestone--done::before {
  border-color: var(--green);
  background: var(--green);
}

.page-about .milestone--now::before {
  border-color: var(--orange);
  background: var(--orange);
  animation: about-pulse 2.4s ease-in-out infinite;
}

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

.page-about .milestone__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 10px;
  padding: 4px 0;
  cursor: pointer;
  list-style: none;
}

.page-about .milestone__head::-webkit-details-marker {
  display: none;
}

.page-about .milestone__head::marker {
  content: "";
}

.page-about .milestone__head::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--text-dim);
}

.page-about .milestone__item[open] .milestone__head::after {
  content: "−";
  color: var(--cyan);
}

.page-about .milestone__phase {
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  color: var(--cyan);
  border: 1px solid var(--line);
  padding: 2px 7px;
}

.page-about .milestone__title {
  font-size: 0.98rem;
  line-height: 1.6;
  color: var(--text);
}

.page-about .milestone__body {
  margin: 10px 0 2px;
  max-width: 64ch;
  font-size: 0.89rem;
  line-height: 1.82;
  color: var(--text-dim);
}

@keyframes about-pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(255, 138, 61, 0.34); }
  50% { box-shadow: 0 0 0 7px rgba(255, 138, 61, 0); }
}

/* —— 服务信息表 —— */
.page-about .infolist {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .infolist__row {
  display: grid;
  gap: 4px;
  padding: 13px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .infolist__key {
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  color: var(--text-dim);
}

.page-about .infolist__val {
  font-size: 0.94rem;
  line-height: 1.7;
  color: var(--text);
  word-break: break-word;
}

/* —— 相关页面 —— */
.page-about .nextlinks {
  display: grid;
  gap: 12px;
  margin: 22px 0 0;
}

.page-about .nextlink {
  display: grid;
  gap: 6px;
  padding: 18px 20px;
  border: 1px solid var(--line);
  color: inherit;
  text-decoration: none;
  transition: border-color 0.18s var(--ease), background-color 0.18s var(--ease);
}

.page-about .nextlink:hover {
  border-color: var(--cyan);
  background: rgba(47, 224, 240, 0.06);
}

.page-about .nextlink__label {
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  color: var(--orange);
}

.page-about .nextlink__title {
  font-size: 1rem;
  font-weight: 500;
  line-height: 1.6;
  color: var(--text);
}

.page-about .nextlink__text {
  font-size: 0.86rem;
  line-height: 1.72;
  color: var(--text-dim);
}

/* —— 平板与桌面 —— */
@media (min-width: 640px) {
  .page-about .datastrip {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .infolist__row {
    grid-template-columns: 148px minmax(0, 1fr);
    gap: 18px;
    align-items: baseline;
  }
}

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

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

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1fr) 264px;
    gap: 48px;
    align-items: end;
    padding: 40px 0 56px;
  }

  .page-about .about-hero__anchor {
    padding: 22px 24px 24px;
  }
}

@media (min-width: 1000px) {
  .page-about .about-shell {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: var(--about-gap);
    padding: 44px 0 96px;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h) + 18px);
    align-self: start;
    border-top: 0;
    border-left: 1px solid var(--line-soft);
    padding: 4px 0 4px 20px;
  }

  .page-about .rail-nav {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .rail-link {
    position: relative;
    border: 0;
    border-radius: 0;
    padding: 7px 0 7px 14px;
    font-size: 0.9rem;
  }

  .page-about .rail-link::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    width: 5px;
    height: 5px;
    margin-top: -2.5px;
    border-radius: 50%;
    background: var(--line);
    transition: background-color 0.16s var(--ease), transform 0.16s var(--ease);
  }

  .page-about .rail-link:hover {
    border-color: transparent;
  }

  .page-about .rail-link[aria-current="true"] {
    color: var(--cyan);
    background: transparent;
    border-color: transparent;
  }

  .page-about .rail-link[aria-current="true"]::before {
    background: var(--cyan);
    transform: scale(1.5);
  }

  .page-about .rail-link[aria-current="true"] .rail-link__idx {
    color: var(--cyan);
  }

  .page-about .datastrip {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-section {
    margin-top: 48px;
    padding-top: 44px;
  }

  .page-about .about-figure {
    margin-top: 30px;
  }
}

@media (min-width: 1200px) {
  .page-about .about-section__title {
    max-width: 28ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .milestone--now::before {
    animation: none;
  }

  .page-about .about-figure img,
  .page-about .rail-link,
  .page-about .nextlink {
    transition: none;
  }
}