.page-about {
  background: var(--paper);
  color: var(--line);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  background: var(--ink-deep);
  color: var(--paper);
  padding: calc(var(--header-h) + 40px) 0 52px;
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: -30%;
  right: -18%;
  width: 62%;
  height: 160%;
  background: radial-gradient(circle at 50% 50%, rgba(47, 191, 166, 0.20), rgba(6, 31, 25, 0) 68%);
  pointer-events: none;
}

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

.page-about .about-hero .breadcrumbs {
  color: rgba(244, 245, 240, 0.62);
  font-size: 13px;
}

.page-about .about-hero .breadcrumbs a {
  color: var(--lime);
}

.page-about .about-hero-grid {
  display: grid;
  gap: 36px;
  margin-top: 26px;
}

.page-about .about-eyebrow {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--lime);
}

.page-about .about-hero h1 {
  margin: 0 0 20px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(36px, 8.6vw, 84px);
  line-height: 0.98;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-hero-lede {
  margin: 0 0 28px;
  max-width: 56ch;
  font-size: 16px;
  line-height: 1.8;
  color: rgba(244, 245, 240, 0.82);
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  padding: 1px;
  background: rgba(244, 245, 240, 0.18);
}

.page-about .about-hero-stat {
  background: var(--ink-deep);
  padding: 16px 14px;
}

.page-about .about-hero-stat dt {
  margin-bottom: 8px;
  font-size: 12px;
  letter-spacing: 0.12em;
  color: rgba(244, 245, 240, 0.52);
}

.page-about .about-hero-stat dd {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin: 0;
}

.page-about .about-num-lg {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 30px;
  font-weight: 700;
  line-height: 1;
  color: var(--lime);
}

.page-about .about-unit {
  font-size: 12px;
  color: rgba(244, 245, 240, 0.58);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-chapter {
  position: relative;
  padding: 56px 0;
}

.page-about .about-chapter--band {
  background: var(--hui);
}

.page-about .about-chapter--deep {
  background: var(--ink-green);
  color: var(--paper);
}

.page-about .about-chapter--open {
  padding-bottom: 88px;
}

.page-about .about-chapter-grid {
  display: grid;
  gap: 22px;
}

.page-about .about-rail {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--hui);
}

.page-about .about-rail-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  color: var(--ink-green);
}

.page-about .about-rail-note {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--stone);
}

.page-about .about-chapter--deep .about-rail {
  border-bottom-color: rgba(244, 245, 240, 0.22);
}

.page-about .about-chapter--deep .about-rail-num {
  color: var(--lime);
}

.page-about .about-chapter--deep .about-rail-note {
  color: rgba(244, 245, 240, 0.6);
}

.page-about .about-slash {
  display: block;
  height: 8px;
  width: 96%;
  margin-bottom: 26px;
  background: var(--lime);
  clip-path: polygon(0 0, 100% 0, calc(100% - 26px) 100%, 0 100%);
}

.page-about .about-slash--lime { background: var(--lime); width: 96%; }
.page-about .about-slash--teal { background: var(--teal); width: 82%; }
.page-about .about-slash--flame { background: var(--flame); width: 68%; }
.page-about .about-slash--stone { background: var(--stone); width: 54%; }

.page-about .about-chapter h2 {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(26px, 5vw, 42px);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--ink-green);
}

.page-about .about-chapter--deep h2 {
  color: var(--paper);
}

.page-about .about-chapter-body > p {
  margin: 0 0 8px;
  max-width: 68ch;
  font-size: 16px;
  line-height: 1.8;
  color: #2B3A34;
}

.page-about .about-chapter--deep .about-chapter-body > p {
  color: rgba(244, 245, 240, 0.82);
}

/* ---------- 四条线 ---------- */
.page-about .about-lines {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  border-top: 1px solid var(--hui);
}

.page-about .about-line {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 14px;
  padding: 22px 0;
  border-bottom: 1px solid var(--hui);
}

.page-about .about-line-idx {
  padding-top: 4px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 15px;
  font-weight: 700;
  color: var(--teal);
}

.page-about .about-line-body h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 20px;
  letter-spacing: 0.01em;
  color: var(--ink-green);
}

.page-about .about-line-body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: #3A4A43;
}

/* ---------- 图 ---------- */
.page-about .about-figure {
  margin: 28px 0 0;
}

.page-about .about-figure--wide {
  margin-top: 32px;
}

.page-about .about-figure .media-frame {
  background: var(--hui);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 22px), calc(100% - 22px) 100%, 0 100%);
}

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

.page-about .media-caption {
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--stone);
}

.page-about .about-chapter--deep .media-caption {
  color: rgba(244, 245, 240, 0.6);
}

/* ---------- 分工分组 ---------- */
.page-about .about-roles-filter {
  margin-top: 30px;
}

.page-about .about-roles {
  display: grid;
  gap: 16px;
  margin-top: 20px;
}

.page-about .about-role {
  position: relative;
  padding: 22px 20px 26px;
  background: var(--paper);
  border-top: 4px solid var(--ink-green);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 20px), calc(100% - 20px) 100%, 0 100%);
}

.page-about .about-role:nth-child(1) { border-top-color: var(--lime); }
.page-about .about-role:nth-child(2) { border-top-color: var(--teal); }
.page-about .about-role:nth-child(3) { border-top-color: var(--flame); }
.page-about .about-role:nth-child(4) { border-top-color: var(--ink-green); }

.page-about .about-role-count {
  display: flex;
  align-items: baseline;
  gap: 3px;
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--stone);
}

.page-about .about-role-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 34px;
  font-weight: 700;
  line-height: 1;
  color: var(--ink-green);
}

.page-about .about-role h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 19px;
  color: var(--ink-green);
}

.page-about .about-role p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: #3A4A43;
}

/* ---------- 数据链路 ---------- */
.page-about .about-flow-list {
  list-style: none;
  margin: 30px 0 0;
  padding: 0 0 0 20px;
  border-left: 2px solid var(--hui);
}

.page-about .about-flow-list li {
  position: relative;
  display: grid;
  gap: 5px;
  padding: 0 0 24px;
}

.page-about .about-flow-list li:last-child {
  padding-bottom: 4px;
}

.page-about .about-flow-list li::before {
  content: "";
  position: absolute;
  left: -27px;
  top: 6px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 0 3px var(--paper);
}

.page-about .about-flow-time {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--ink-green);
}

.page-about .about-flow-text {
  font-size: 15px;
  line-height: 1.75;
  color: #3A4A43;
}

.page-about .about-flow-figure {
  margin: 30px 0 0;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-flow {
  display: block;
  width: 100%;
  min-width: 620px;
  height: auto;
}

.page-about .about-flow-line {
  stroke: var(--hui);
  stroke-width: 2;
}

.page-about .about-flow-node {
  fill: var(--paper);
  stroke: var(--teal);
  stroke-width: 4;
}

.page-about .about-flow-node--start {
  stroke: var(--teal);
  fill: var(--teal);
}

.page-about .about-flow-node--end {
  stroke: var(--flame);
  fill: var(--flame);
}

.page-about .about-flow-label {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 600;
  fill: var(--ink-green);
}

.page-about .about-flow-sub {
  font-family: var(--font-body);
  font-size: 13px;
  fill: var(--stone);
}

/* ---------- 版本演进 ---------- */
.page-about .about-ver {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .about-ver-item {
  position: relative;
  padding: 20px 0 0;
  border-top: 3px solid var(--hui);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-ver-item:hover,
.page-about .about-ver-item:focus-within {
  transform: translateY(-4px);
  border-top-color: var(--lime);
}

.page-about .about-ver-tag {
  display: inline-block;
  margin-bottom: 12px;
  padding: 3px 12px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--paper);
  background: var(--ink-green);
}

.page-about .about-ver-item h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 21px;
  color: var(--ink-green);
}

.page-about .about-ver-item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: #3A4A43;
}

/* ---------- 覆盖与合作 ---------- */
.page-about .about-eco {
  list-style: none;
  margin: 32px 0 0;
  padding: 0;
  display: grid;
  gap: 22px;
}

.page-about .about-eco-item {
  display: grid;
  grid-template-columns: 60px minmax(0, 1fr);
  gap: 16px;
  align-items: start;
  padding-top: 18px;
  border-top: 2px solid rgba(244, 245, 240, 0.22);
}

.page-about .about-eco-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 44px;
  font-weight: 700;
  line-height: 0.9;
  color: var(--lime);
}

.page-about .about-eco-body h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 19px;
  color: var(--paper);
}

.page-about .about-eco-body p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(244, 245, 240, 0.78);
}

/* ---------- 合作入口 ---------- */
.page-about .about-needs {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .about-need {
  padding: 20px 22px;
  background: var(--paper);
  border-left: 4px solid var(--teal);
}

.page-about .about-need:nth-child(2) { border-left-color: var(--lime); }
.page-about .about-need:nth-child(3) { border-left-color: var(--flame); }

.page-about .about-need h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 18px;
  color: var(--ink-green);
}

.page-about .about-need p {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: #3A4A43;
}

.page-about .about-cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.page-about .trust-line {
  margin-top: 34px;
}

.page-about .about-backlinks {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  margin: 24px 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
}

.page-about .about-backlinks .backlink {
  color: var(--ink-green);
  text-decoration: none;
  border-bottom: 1px solid var(--stone);
  padding-bottom: 2px;
}

.page-about .about-backlinks .backlink:hover {
  color: var(--flame);
  border-bottom-color: var(--flame);
}

/* ---------- 断点 ---------- */
@media (min-width: 700px) {
  .page-about .about-roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
  }

  .page-about .about-lines .about-line {
    grid-template-columns: 56px minmax(0, 1fr);
    gap: 24px;
  }

  .page-about .about-eco-item {
    grid-template-columns: 84px minmax(0, 1fr);
    gap: 24px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: calc(var(--header-h) + 60px) 0 72px;
  }

  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 0.65fr);
    gap: 56px;
    align-items: end;
  }

  .page-about .about-chapter {
    padding: 84px 0;
  }

  .page-about .about-chapter--open {
    padding-bottom: 120px;
  }

  .page-about .about-chapter-grid {
    grid-template-columns: 104px minmax(0, 1fr);
    gap: 48px;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h-sm) + 32px);
    align-self: start;
    flex-direction: column;
    align-items: flex-start;
    gap: 14px;
    padding: 0 0 0 16px;
    border-bottom: 0;
    border-left: 2px solid var(--hui);
  }

  .page-about .about-chapter--deep .about-rail {
    border-left-color: rgba(244, 245, 240, 0.22);
  }

  .page-about .about-rail-note {
    writing-mode: vertical-rl;
    text-orientation: mixed;
  }

  .page-about .about-eco {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 28px;
  }

  .page-about .about-eco-item {
    grid-template-columns: minmax(0, 1fr);
    gap: 12px;
    padding-top: 22px;
  }

  .page-about .about-needs {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
  }
}

@media (min-width: 880px) {
  .page-about .about-ver {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
    position: relative;
    padding-top: 6px;
  }

  .page-about .about-ver::before {
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    top: 22px;
    height: 2px;
    background: linear-gradient(90deg, var(--teal) 0%, var(--lime) 55%, var(--flame) 100%);
  }

  .page-about .about-ver-item {
    padding: 46px 20px 24px;
    border-top: 0;
    background: rgba(244, 245, 240, 0.66);
  }

  .page-about .about-ver-item::before {
    content: "";
    position: absolute;
    top: 16px;
    left: 20px;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--teal);
    box-shadow: 0 0 0 4px var(--paper);
  }

  .page-about .about-ver-item:nth-child(2)::before { background: var(--lime); }
  .page-about .about-ver-item:nth-child(3)::before { background: var(--flame); }

  .page-about .about-ver-item:hover,
  .page-about .about-ver-item:focus-within {
    background: #ffffff;
    transform: translateY(-4px);
  }
}

@media (min-width: 1100px) {
  .page-about .about-roles {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-ver-item,
  .page-about .about-role,
  .page-about .about-need {
    transition: none;
  }

  .page-about .about-ver-item:hover,
  .page-about .about-ver-item:focus-within {
    transform: none;
  }
}