.page-about {
  --about-ladder-axis: 10px;
  --about-flow-gap: clamp(24px, 3.6vw, 48px);
  background-color: var(--c-deep);
  color: var(--c-silver);
  overflow-x: clip;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(32px, 5.5vw, 72px) 0 clamp(40px, 6vw, 88px);
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 1px;
  background: linear-gradient(90deg, var(--cyan-line), rgba(61, 224, 194, 0) 42%);
  pointer-events: none;
}

.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: clamp(22px, 3.4vw, 42px);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--c-mist);
}

.page-about .breadcrumb a {
  color: var(--c-mist);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

.page-about .breadcrumb-sep {
  color: rgba(201, 214, 223, 0.34);
}

.page-about .about-hero .eyebrow {
  display: block;
  margin: 0 0 clamp(14px, 2vw, 22px);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--c-cyan);
}

.page-about .about-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(32px, 5vw, 56px);
  align-items: start;
}

.page-about h1 {
  margin: 0 0 clamp(18px, 2.4vw, 28px);
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 5.4vw, 62px);
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--c-glass);
  max-width: 15em;
}

.page-about .about-lead {
  margin: 0;
  max-width: 44em;
  font-size: clamp(15.5px, 1.24vw, 17.5px);
  line-height: 1.88;
  color: var(--c-silver);
}

.page-about .about-facts {
  margin: 0;
  padding: clamp(20px, 2.6vw, 28px);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(16px, 2.2vw, 24px) clamp(14px, 2vw, 22px);
  background: rgba(14, 42, 69, 0.62);
  border: 1px solid var(--line);
  backdrop-filter: blur(6px);
}

.page-about .about-fact {
  margin: 0;
  padding-left: 12px;
  border-left: 1px solid var(--line-strong);
}

.page-about .about-fact dt {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--c-mist);
}

.page-about .about-fact dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(20px, 2.2vw, 27px);
  line-height: 1;
  color: var(--c-cyan);
  letter-spacing: 0.01em;
}

/* ---------- 主体骨架 ---------- */
.page-about .about-main {
  padding-top: clamp(44px, 6.5vw, 92px);
  padding-bottom: 0;
}

.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 44px);
}

.page-about .about-index-title {
  margin: 0 0 14px;
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-mist);
}

.page-about .about-index-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
}

.page-about .about-index-list .track-node {
  display: inline-flex;
  align-items: baseline;
  gap: 9px;
  padding: 5px 0;
  font-size: 13.5px;
  color: var(--c-mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.page-about .about-index-list .track-node .mono {
  font-size: 11px;
  letter-spacing: 0.06em;
  opacity: 0.7;
}

.page-about .about-index-list .track-node:hover {
  color: var(--c-silver);
}

.page-about .about-index-list .track-node.is-active {
  color: var(--c-cyan);
  border-bottom-color: var(--cyan-line);
}

.page-about .about-index-list .track-node.is-active .mono {
  opacity: 1;
}

/* ---------- 章节 ---------- */
.page-about .about-flow > * + * {
  margin-top: clamp(48px, 7vw, 104px);
}

.page-about .about-flow > .about-flow-lead {
  margin-top: 0;
}

.page-about .about-section {
  padding-top: clamp(40px, 6vw, 84px);
  border-top: 1px solid var(--line-soft);
}

.page-about .about-flow > .about-section:first-child {
  padding-top: 0;
  border-top: none;
}

.page-about .about-section .section-head {
  margin-bottom: clamp(26px, 3.6vw, 46px);
}

.page-about .about-section .eyebrow {
  display: block;
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--c-cyan);
}

.page-about .about-section .section-title {
  margin: 0 0 clamp(12px, 1.6vw, 18px);
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(23px, 3vw, 37px);
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--c-glass);
  max-width: 20em;
}

.page-about .about-section .section-lead {
  margin: 0;
  max-width: 42em;
  font-size: clamp(15px, 1.16vw, 16.5px);
  line-height: 1.82;
  color: var(--c-silver);
}

/* ---------- 01 档案起点 ---------- */
.page-about .about-feature {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--about-flow-gap);
  align-items: start;
}

.page-about .about-feature-copy p {
  margin: 0 0 1.15em;
  font-size: clamp(15px, 1.16vw, 16.5px);
  line-height: 1.9;
  color: var(--c-silver);
}

.page-about .about-feature-copy p:last-child {
  margin-bottom: 0;
}

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

.page-about .about-feature-media .figure-media {
  position: relative;
  aspect-ratio: 3 / 2;
  overflow: hidden;
  background: var(--c-mid);
  border: 1px solid var(--line);
}

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

.page-about .about-feature-media .figure-media img,
.page-about .about-workflow-figure .figure-media img,
.page-about .about-versions-figure .figure-media img {
  height: 100%;
}

.page-about .figure-caption {
  margin-top: 12px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.03em;
  line-height: 1.7;
  color: var(--c-mist);
}

/* ---------- 02 团队 ---------- */
.page-about .team-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .team-row {
  display: grid;
  grid-template-columns: 60px minmax(0, 1fr);
  gap: clamp(14px, 2.4vw, 32px);
  padding: clamp(18px, 2.4vw, 30px) clamp(6px, 1vw, 14px);
  border-bottom: 1px solid var(--line-soft);
  transition: background-color 0.22s ease;
}

.page-about .team-row:hover {
  background-color: rgba(201, 214, 223, 0.035);
}

.page-about .team-num {
  font-size: clamp(20px, 2.4vw, 30px);
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--c-cyan);
  text-align: right;
  padding-right: 14px;
  border-right: 1px solid var(--line);
}

.page-about .team-body h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: clamp(16px, 1.55vw, 19px);
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--c-glass);
}

.page-about .team-body p {
  margin: 0;
  max-width: 40em;
  font-size: 15.5px;
  line-height: 1.82;
  color: var(--c-silver);
}

.page-about .team-total {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  padding: clamp(16px, 2vw, 24px) clamp(6px, 1vw, 14px) 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--c-mist);
}

.page-about .team-total .num {
  font-size: clamp(18px, 2vw, 24px);
  color: var(--c-cyan);
  letter-spacing: 0.01em;
}

/* ---------- 03 三步成稿 ---------- */
.page-about .steps {
  border-top: 1px solid var(--line);
}

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

.page-about .step summary {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: clamp(12px, 2vw, 24px);
  padding: clamp(16px, 2.2vw, 26px) clamp(6px, 1vw, 14px);
  cursor: pointer;
  list-style: none;
  transition: background-color 0.22s ease;
}

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

.page-about .step summary:hover {
  background-color: rgba(201, 214, 223, 0.035);
}

.page-about .step-index {
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--c-mist);
  white-space: nowrap;
}

.page-about .step-name {
  font-family: var(--font-display);
  font-size: clamp(16px, 1.7vw, 21px);
  letter-spacing: -0.01em;
  color: var(--c-glass);
}

.page-about .step-chevron {
  position: relative;
  width: 15px;
  height: 15px;
  flex: none;
}

.page-about .step-chevron::before,
.page-about .step-chevron::after {
  content: "";
  position: absolute;
  background: var(--c-mist);
  transition: transform 0.25s ease, background-color 0.25s ease;
}

.page-about .step-chevron::before {
  left: 0;
  top: 7px;
  width: 15px;
  height: 1.5px;
}

.page-about .step-chevron::after {
  left: 7px;
  top: 0;
  width: 1.5px;
  height: 15px;
}

.page-about .step[open] .step-chevron::after {
  transform: scaleY(0);
}

.page-about .step[open] .step-chevron::before {
  background: var(--c-cyan);
}

.page-about .step-body {
  padding: 0 clamp(6px, 1vw, 14px) clamp(18px, 2.4vw, 30px);
}

.page-about .step-body p {
  margin: 0;
  max-width: 44em;
  font-size: 15.5px;
  line-height: 1.86;
  color: var(--c-silver);
}

.page-about .about-workflow-figure .figure-media {
  aspect-ratio: 2 / 1;
  overflow: hidden;
  background: var(--c-mid);
  border: 1px solid var(--line);
}

/* ---------- 04 版本迭代 ---------- */
.page-about .ladder {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0 0 0 calc(var(--about-ladder-axis) + 24px);
}

.page-about .ladder::before {
  content: "";
  position: absolute;
  left: var(--about-ladder-axis);
  top: 12px;
  bottom: clamp(30px, 4vw, 46px);
  width: 1px;
  background: linear-gradient(to bottom, var(--cyan-line), rgba(15, 122, 107, 0.5) 55%, rgba(15, 122, 107, 0.08));
}

.page-about .ladder-item {
  position: relative;
  padding-bottom: clamp(24px, 3.4vw, 38px);
}

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

.page-about .ladder-item::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 6px;
  width: 9px;
  height: 9px;
  box-sizing: border-box;
  border: 1.5px solid var(--c-mist);
  border-radius: 50%;
  background: var(--c-deep);
  transition: border-color 0.25s ease, background-color 0.25s ease, box-shadow 0.25s ease;
}

.page-about .ladder-item:hover::before {
  border-color: var(--c-cyan);
  background: var(--c-cyan);
  box-shadow: 0 0 0 4px rgba(61, 224, 194, 0.14);
}

.page-about .ladder-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 8px;
}

.page-about .ladder-ver {
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--c-cyan);
}

.page-about .ladder-year {
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--c-mist);
}

.page-about .ladder-body h3 {
  margin: 0 0 7px;
  font-family: var(--font-display);
  font-size: clamp(16px, 1.65vw, 20px);
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--c-glass);
}

.page-about .ladder-body p {
  margin: 0 0 10px;
  max-width: 42em;
  font-size: 15.5px;
  line-height: 1.82;
  color: var(--c-silver);
}

.page-about .ladder-extra {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.05em;
  color: var(--c-mist);
  opacity: 0.55;
  transition: opacity 0.25s ease, color 0.25s ease;
}

@media (hover: hover) and (min-width: 760px) {
  .page-about .ladder-item:hover .ladder-extra {
    opacity: 1;
    color: var(--c-teal);
    color: #0F7A6B;
    color: var(--c-cyan);
  }
}

.page-about .about-versions-figure .figure-media {
  aspect-ratio: 2 / 1;
  overflow: hidden;
  background: var(--c-mid);
  border: 1px solid var(--line);
}

/* ---------- 鱼鳞分隔 ---------- */
.page-about .scale-rule {
  display: block;
  width: 100%;
  height: 24px;
  color: var(--line);
  margin: 0;
}

/* ---------- 05 合作 ---------- */
.page-about .partner-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(16px, 2.4vw, 28px);
}

.page-about .partner-card {
  padding: clamp(22px, 3vw, 34px);
  border: 1px solid var(--line);
  border-radius: 2px;
}

.page-about .partner-label {
  margin: 0 0 14px;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--c-cyan);
}

.page-about .partner-card h3 {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: clamp(17px, 1.7vw, 20px);
  line-height: 1.32;
  letter-spacing: -0.01em;
  color: var(--c-glass);
}

.page-about .partner-card p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.84;
  color: var(--c-silver);
}

/* ---------- 06 准则 ---------- */
.page-about .principles {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .principles li {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr);
  gap: clamp(14px, 2vw, 26px);
  padding: clamp(18px, 2.4vw, 28px) 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .principles li:last-child {
  border-bottom: 1px solid var(--line-soft);
}

.page-about .principle-num {
  font-size: 14px;
  letter-spacing: 0.1em;
  color: var(--c-cyan);
  padding-top: 3px;
}

.page-about .principles h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: clamp(16px, 1.55vw, 19px);
  line-height: 1.34;
  letter-spacing: -0.01em;
  color: var(--c-glass);
}

.page-about .principles p {
  margin: 0;
  max-width: 44em;
  font-size: 15.5px;
  line-height: 1.84;
  color: var(--c-silver);
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  padding-top: clamp(40px, 6vw, 84px);
  border-top: 1px solid var(--line);
}

.page-about .about-cta .eyebrow {
  display: block;
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c-cyan);
}

.page-about .about-cta h2 {
  margin: 0 0 clamp(14px, 1.8vw, 20px);
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(23px, 3vw, 36px);
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--c-glass);
}

.page-about .about-cta p {
  margin: 0 0 clamp(24px, 3vw, 36px);
  max-width: 44em;
  font-size: clamp(15px, 1.16vw, 16.5px);
  line-height: 1.86;
  color: var(--c-silver);
}

.page-about .about-cta-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 14px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 760px) {
  .page-about .about-feature {
    grid-template-columns: minmax(0, 1.04fr) minmax(0, 0.96fr);
  }

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

  .page-about .team-row {
    grid-template-columns: 76px minmax(0, 1fr);
  }

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

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    column-gap: var(--grid-gap);
  }

  .page-about .about-hero-copy {
    grid-column: 1 / span 7;
  }

  .page-about .about-hero-side {
    grid-column: 9 / span 4;
  }
}

@media (min-width: 1024px) {
  .page-about {
    --about-ladder-axis: 16px;
  }

  .page-about .about-body {
    grid-template-columns: minmax(176px, 216px) minmax(0, 1fr);
    column-gap: clamp(36px, 5.5vw, 92px);
  }

  .page-about .about-index {
    position: sticky;
    top: calc(var(--header-h) + 32px);
    align-self: start;
  }

  .page-about .about-index-list {
    display: block;
  }

  .page-about .about-index-list li + li {
    margin-top: 4px;
  }

  .page-about .about-index-list .track-node {
    width: 100%;
    padding: 7px 0;
  }
}

@media (max-width: 420px) {
  .page-about .team-row {
    grid-template-columns: 44px minmax(0, 1fr);
    gap: 12px;
  }

  .page-about .team-num {
    font-size: 18px;
    padding-right: 10px;
  }

  .page-about .step summary {
    grid-template-columns: minmax(0, 1fr) auto;
    row-gap: 6px;
  }

  .page-about .step-index {
    grid-column: 1 / -1;
  }
}