.page-about {
  position: relative;
  background: var(--ink-900);
  color: var(--white);
  font-family: var(--font-head);
  overflow-x: clip;
}

.page-about::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, rgba(42, 58, 52, 0.5) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(42, 58, 52, 0.5) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
  z-index: 0;
}

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

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  padding-top: clamp(20px, 3vw, 34px);
  font-size: 12px;
  letter-spacing: 0.06em;
}

.page-about .crumb-link {
  color: var(--moss);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.page-about .crumb-link:hover,
.page-about .crumb-link:focus-visible {
  color: var(--lime);
  border-bottom-color: var(--lime);
}

.page-about .crumb-sep {
  color: var(--line);
}

.page-about .crumb-current {
  color: var(--silver);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: 28px;
  padding: clamp(34px, 6vw, 84px) 0 clamp(30px, 5vw, 60px);
  border-bottom: 1px solid var(--line);
}

.page-about .hero-year {
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.page-about .year-num {
  font-size: clamp(38px, 8vw, 76px);
  font-weight: 600;
  line-height: 0.92;
  letter-spacing: -0.03em;
  color: var(--lime);
}

.page-about .year-bar {
  display: block;
  flex: 1 1 auto;
  min-width: 24px;
  height: 1px;
  background: var(--line);
  align-self: center;
}

.page-about .year-tail {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--moss);
  white-space: nowrap;
}

.page-about .eyebrow {
  margin: 0 0 14px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--silver);
  text-transform: uppercase;
}

.page-about .about-hero h1 {
  margin: 0 0 20px;
  font-size: clamp(28px, 5.6vw, 58px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
  max-width: 16ch;
}

.page-about .about-hero .lede {
  margin: 0 0 26px;
  max-width: 40ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--silver);
}

.page-about .hero-marks {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .hero-marks li {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 14px 22px 14px 0;
  margin-right: 22px;
  border-right: 1px solid var(--line);
}

.page-about .hero-marks li:last-child {
  border-right: 0;
  margin-right: 0;
}

.page-about .mark-num {
  font-size: 19px;
  font-weight: 600;
  color: var(--lime);
  letter-spacing: -0.01em;
}

.page-about .mark-text {
  font-size: 13px;
  color: var(--moss);
}

/* ---------- 主网格与章节索引 ---------- */
.page-about .about-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
  padding-bottom: clamp(48px, 8vw, 96px);
}

.page-about .about-index {
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

.page-about .index-label {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--moss);
}

.page-about .chapter-list {
  display: flex;
  gap: 0;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .chapter-list li {
  flex: 0 0 auto;
}

.page-about .chapter-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 14px 9px 0;
  margin-right: 14px;
  font-size: 13px;
  color: var(--silver);
  text-decoration: none;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.page-about .chapter-link:hover,
.page-about .chapter-link:focus-visible {
  color: var(--lime);
  border-bottom-color: var(--lime);
}

.page-about .chapter-no {
  font-size: 11px;
  color: var(--moss);
}

.page-about .chapter-link:hover .chapter-no,
.page-about .chapter-link:focus-visible .chapter-no {
  color: var(--lime);
}

.page-about .about-main {
  min-width: 0;
  max-width: 760px;
}

/* ---------- 章节 ---------- */
.page-about .chapter {
  scroll-margin-top: 90px;
}

.page-about .chapter + .chapter {
  margin-top: clamp(48px, 7vw, 88px);
}

.page-about .chapter-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding-bottom: 14px;
  margin-bottom: 22px;
  border-bottom: 1px solid var(--line);
}

.page-about .chapter-num {
  font-size: 13px;
  font-weight: 600;
  color: var(--lime);
  letter-spacing: 0.1em;
}

.page-about .chapter-title {
  margin: 0;
  font-size: clamp(21px, 3.2vw, 30px);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.page-about .chapter-body p {
  margin: 0 0 18px;
  max-width: 38em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--white);
}

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

.page-about .chapter-tail {
  margin: 22px 0 0;
  max-width: 38em;
  font-size: 14px;
  line-height: 1.8;
  color: var(--silver);
}

.page-about .text-link {
  color: var(--lime);
  text-decoration: none;
  border-bottom: 1px solid rgba(200, 244, 90, 0.4);
  transition: border-color 0.2s ease;
}

.page-about .text-link:hover,
.page-about .text-link:focus-visible {
  border-bottom-color: var(--lime);
}

/* ---------- 图片 ---------- */
.page-about .chapter-media {
  margin: 0 0 26px;
}

.page-about .media {
  position: relative;
  background-color: var(--ink-700);
  background-image:
    linear-gradient(to right, rgba(42, 58, 52, 0.7) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(42, 58, 52, 0.7) 1px, transparent 1px);
  background-size: 32px 32px;
  border: 1px solid var(--line);
  overflow: hidden;
}

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

.page-about .media--wide img {
  aspect-ratio: 3 / 2;
}

.page-about .media--card img {
  aspect-ratio: 4 / 3;
}

.page-about .media-caption {
  display: block;
  padding: 10px 14px;
  border-top: 1px solid var(--line);
  background: var(--ink-800);
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--moss);
}

/* ---------- 数据带 ---------- */
.page-about .beam {
  margin: clamp(40px, 6vw, 72px) 0;
}

.page-about .beam-inner {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .beam-item {
  background: var(--ink-800);
  padding: 18px 14px 20px;
}

.page-about .beam-num {
  display: block;
  font-size: clamp(23px, 3.6vw, 34px);
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--lime);
}

.page-about .beam-unit {
  font-size: 0.48em;
  margin-left: 3px;
  letter-spacing: 0;
  color: var(--moss);
}

.page-about .beam-label {
  display: block;
  margin-top: 9px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--silver);
}

/* ---------- 四条业务线 ---------- */
.page-about .line-list {
  border-top: 1px solid var(--line);
}

.page-about .line-item {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 14px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
  transition: background 0.2s ease;
}

.page-about .line-item:hover {
  background: rgba(20, 48, 42, 0.5);
}

.page-about .line-num {
  font-size: 13px;
  font-weight: 600;
  color: var(--amber);
  letter-spacing: 0.08em;
  padding-top: 4px;
}

.page-about .line-title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.005em;
}

.page-about .line-text {
  margin: 0;
  max-width: 36em;
  font-size: 15px;
  line-height: 1.8;
  color: var(--silver);
}

/* ---------- 校核区：折叠 + 图片 ---------- */
.page-about .split-inline {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  margin: 26px 0;
}

.page-about .split-media {
  margin: 0;
}

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

.page-about .accordion-item {
  border-bottom: 1px solid var(--line);
}

.page-about .accordion-btn {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  padding: 15px 2px;
  background: transparent;
  border: 0;
  color: var(--white);
  font-family: inherit;
  font-size: 15px;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  transition: color 0.2s ease;
}

.page-about .accordion-btn:hover,
.page-about .accordion-btn:focus-visible {
  color: var(--lime);
}

.page-about .accordion-num {
  font-size: 11px;
  color: var(--moss);
  letter-spacing: 0.1em;
}

.page-about .accordion-btn[aria-expanded="true"] .accordion-num {
  color: var(--lime);
}

.page-about .accordion-title {
  flex: 1 1 auto;
}

.page-about .accordion-sign {
  font-size: 16px;
  color: var(--lime);
  line-height: 1;
}

.page-about .accordion-btn[aria-expanded="true"] .accordion-sign {
  color: var(--amber);
}

.page-about .accordion-panel {
  overflow: hidden;
}

.page-about .accordion-inner {
  padding: 0 2px 18px 34px;
}

.page-about .accordion-inner p {
  margin: 0;
  max-width: 34em;
  font-size: 14px;
  line-height: 1.8;
  color: var(--silver);
  border-left: 1px solid var(--line);
  padding-left: 14px;
}

/* ---------- 处理流程 ---------- */
.page-about .flow {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .flow-step {
  position: relative;
  padding: 16px 0 16px 26px;
  border-bottom: 1px solid var(--line);
}

.page-about .flow-dot {
  position: absolute;
  left: 0;
  top: 22px;
  width: 10px;
  height: 10px;
  border: 1px solid var(--lime);
  background: var(--ink-900);
  transform: rotate(45deg);
}

.page-about .flow-name {
  display: block;
  font-size: 15px;
  font-weight: 600;
  color: var(--white);
}

.page-about .flow-meta {
  display: block;
  margin-top: 6px;
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--moss);
}

/* ---------- 团队矩阵表 ---------- */
.page-about .matrix-scroll {
  margin-top: 26px;
  overflow-x: auto;
  border: 1px solid var(--line);
}

.page-about .matrix {
  width: 100%;
  min-width: 540px;
  border-collapse: collapse;
  font-size: 14px;
}

.page-about .matrix th,
.page-about .matrix td {
  padding: 15px 16px;
  text-align: left;
  vertical-align: top;
  line-height: 1.7;
  border-bottom: 1px solid var(--line);
  border-right: 1px solid var(--line);
}

.page-about .matrix thead th {
  background: var(--ink-700);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.14em;
  color: var(--lime);
  text-transform: uppercase;
}

.page-about .matrix tbody th {
  width: 92px;
  font-size: 14px;
  font-weight: 600;
  color: var(--amber);
  background: var(--ink-800);
}

.page-about .matrix tbody td {
  color: var(--silver);
}

.page-about .matrix tbody tr:last-child th,
.page-about .matrix tbody tr:last-child td {
  border-bottom: 0;
}

.page-about .matrix th:last-child,
.page-about .matrix td:last-child {
  border-right: 0;
}

/* ---------- 长期积累 ---------- */
.page-about .asset-grid {
  margin: 26px 0;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .asset {
  background: var(--ink-800);
  padding: 22px 18px 24px;
}

.page-about .asset-num {
  display: block;
  font-size: clamp(28px, 4.4vw, 40px);
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--lime);
}

.page-about .asset-title {
  margin: 10px 0 12px;
  font-size: 15px;
  font-weight: 700;
  color: var(--white);
}

.page-about .asset-text {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--silver);
}

/* ---------- 下一章索引条 ---------- */
.page-about .next-link {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 30px;
  padding: 13px 16px;
  border: 1px solid var(--line);
  border-left: 2px solid var(--lime);
  background: var(--ink-800);
  text-decoration: none;
  transition: background 0.2s ease, transform 0.2s ease;
}

.page-about .next-link:hover,
.page-about .next-link:focus-visible {
  background: var(--ink-700);
  transform: translateX(2px);
}

.page-about .next-label {
  font-size: 10px;
  letter-spacing: 0.18em;
  color: var(--moss);
}

.page-about .next-name {
  flex: 1 1 auto;
  font-size: 14px;
  font-weight: 600;
  color: var(--white);
}

.page-about .next-arrow {
  font-size: 14px;
  color: var(--lime);
}

/* ---------- CTA 与收束带 ---------- */
.page-about .cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.page-about .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 13px 24px;
  border: 1px solid transparent;
  border-radius: 0;
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.page-about .btn--primary {
  background: var(--lime);
  color: var(--lime-ink);
}

.page-about .btn--primary:hover,
.page-about .btn--primary:focus-visible {
  background: var(--white);
}

.page-about .btn--ghost {
  background: transparent;
  border-color: var(--line);
  color: var(--silver);
}

.page-about .btn--ghost:hover,
.page-about .btn--ghost:focus-visible {
  border-color: var(--lime);
  color: var(--lime);
}

.page-about .signoff {
  margin-top: clamp(48px, 7vw, 84px);
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

.page-about .signoff-mark {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--silver);
}

.page-about .signoff-line {
  margin: 0 0 8px;
  font-size: 12px;
  line-height: 1.8;
  letter-spacing: 0.04em;
  color: var(--moss);
  word-break: break-word;
}

.page-about .signoff-note {
  margin: 0;
  font-size: 12px;
  line-height: 1.8;
  color: var(--moss);
}

/* ---------- 显现动效（渐进增强） ---------- */
@keyframes aboutAutoReveal {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.page-about [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  animation: aboutAutoReveal 0.6s ease 1.6s forwards;
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.page-about [data-reveal].is-visible {
  opacity: 1;
  transform: none;
  animation: none;
}

/* ---------- 断点 ---------- */
@media (min-width: 620px) {
  .page-about .beam-inner {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .beam-item {
    padding: 22px 18px 24px;
  }

  .page-about .flow {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    border-top: 1px solid var(--line);
  }

  .page-about .flow-step {
    padding: 46px 18px 18px 0;
    border-bottom: 0;
    border-right: 1px solid var(--line);
  }

  .page-about .flow-step:last-child {
    border-right: 0;
  }

  .page-about .flow-dot {
    top: 26px;
    left: 0;
  }

  .page-about .flow-step::after {
    content: "";
    position: absolute;
    top: 30px;
    left: 12px;
    right: 0;
    height: 1px;
    background: var(--line);
  }

  .page-about .flow-step:last-child::after {
    display: none;
  }

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

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(200px, 0.62fr) 1.38fr;
    gap: clamp(34px, 5vw, 76px);
    align-items: end;
  }

  .page-about .hero-year {
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
  }

  .page-about .year-bar {
    width: 100%;
    flex: 0 0 auto;
  }

  .page-about .about-grid {
    grid-template-columns: 196px minmax(0, 1fr);
    gap: clamp(30px, 4.5vw, 68px);
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: calc(var(--topbar-h, 54px) + 28px);
    border-top: 1px solid var(--line);
  }

  .page-about .chapter-list {
    flex-direction: column;
    overflow-x: visible;
    padding-bottom: 0;
  }

  .page-about .chapter-link {
    width: 100%;
    padding: 11px 0;
    margin-right: 0;
    border-bottom: 1px solid transparent;
    border-left: 2px solid transparent;
    padding-left: 12px;
    white-space: normal;
    line-height: 1.5;
  }

  .page-about .chapter-link:hover,
  .page-about .chapter-link:focus-visible {
    border-bottom-color: transparent;
    border-left-color: var(--lime);
    background: var(--ink-800);
  }

  .page-about .split-inline {
    grid-template-columns: minmax(0, 1fr) minmax(0, 300px);
    gap: clamp(24px, 3vw, 44px);
    align-items: start;
  }
}

@media (min-width: 1180px) {
  .page-about .about-grid {
    grid-template-columns: 208px minmax(0, 780px) minmax(0, 1fr);
  }

  .page-about .about-main {
    max-width: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about [data-reveal] {
    opacity: 1;
    transform: none;
    animation: none;
    transition: none;
  }

  .page-about .next-link,
  .page-about .line-item {
    transition: none;
  }
}