.page-about {
  --about-rail-w: 132px;
  --about-tight: clamp(20px, 2.6vw, 30px);
  background: var(--c-deep);
  color: var(--text-on-dark);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(20px, 3vw, 40px) 0 clamp(56px, 9vw, 118px);
  background:
    radial-gradient(115% 88% at 88% -12%, rgba(53, 224, 216, 0.13), transparent 62%),
    radial-gradient(78% 58% at 0% 104%, rgba(255, 122, 61, 0.08), transparent 72%),
    var(--c-deep);
  color: var(--text-on-dark);
}

.page-about .about-hero .blueprint-lines {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.5;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(38px, 6vw, 62px);
}

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

.page-about .about-hero__title {
  margin: clamp(20px, 3vw, 34px) 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.95rem, 5.6vw, 3.9rem);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--c-pearl);
}

.page-about .about-hero__lede {
  margin: clamp(16px, 2vw, 24px) 0 0;
  max-width: 34em;
  font-size: clamp(1rem, 1.3vw, 1.0625rem);
  line-height: 1.8;
  color: var(--text-on-dark-soft);
}

.page-about .about-hero__actions {
  margin-top: clamp(24px, 3vw, 36px);
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-hero__stats {
  display: grid;
  min-width: 0;
}

.page-about .about-stat {
  display: grid;
  grid-template-columns: auto auto;
  grid-template-areas:
    "num unit"
    "label label";
  justify-content: start;
  align-items: baseline;
  column-gap: 10px;
  row-gap: 6px;
  padding: clamp(16px, 2vw, 22px) 0;
  border-top: 1px solid var(--line-on-dark);
}

.page-about .about-stat:last-child {
  border-bottom: 1px solid var(--line-on-dark);
}

.page-about .about-stat__num {
  grid-area: num;
  font-size: clamp(1.8rem, 4vw, 2.75rem);
  font-weight: 500;
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--c-cyan);
}

.page-about .about-stat__unit {
  grid-area: unit;
  font-size: 0.85rem;
  letter-spacing: 0.04em;
  color: var(--c-orange);
}

.page-about .about-stat__label {
  grid-area: label;
  font-size: 0.92rem;
  line-height: 1.6;
  color: var(--text-on-dark-soft);
}

@media (min-width: 900px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
    column-gap: clamp(40px, 6vw, 92px);
  }
}

/* ---------- 三类麻烦 ---------- */

.page-about .about-troubles__head {
  margin-bottom: clamp(26px, 3.6vw, 44px);
}

.page-about .about-troubles__list {
  display: grid;
}

.page-about .about-trouble {
  display: grid;
  gap: 12px;
  padding: clamp(22px, 2.6vw, 30px) 0;
  border-top: 1px solid var(--line-on-light);
}

.page-about .about-trouble:last-child {
  border-bottom: 1px solid var(--line-on-light);
}

.page-about .about-trouble__meta {
  display: grid;
  gap: 8px;
  justify-items: start;
  align-content: start;
}

.page-about .about-trouble__scene {
  font-size: 0.75rem;
  line-height: 1.5;
  letter-spacing: 0.02em;
  color: var(--c-mist);
}

.page-about .about-trouble__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.05rem, 2.1vw, 1.35rem);
  line-height: 1.4;
  letter-spacing: -0.01em;
  color: var(--c-ink);
}

.page-about .about-trouble__body {
  margin: 0;
  font-size: 0.9688rem;
  line-height: 1.8;
  color: var(--c-slate);
}

@media (min-width: 720px) {
  .page-about .about-troubles__list {
    grid-template-columns: repeat(12, minmax(0, 1fr));
  }
  .page-about .about-trouble:nth-child(1) { grid-column: 1 / span 11; }
  .page-about .about-trouble:nth-child(2) { grid-column: 3 / span 10; }
  .page-about .about-trouble:nth-child(3) { grid-column: 1 / span 9; }
}

@media (min-width: 860px) {
  .page-about .about-trouble {
    grid-template-columns: minmax(150px, 0.6fr) minmax(0, 1fr) minmax(0, 1.5fr);
    align-items: start;
    column-gap: clamp(20px, 3vw, 52px);
    row-gap: 0;
  }
  .page-about .about-trouble__meta { grid-column: 1; }
  .page-about .about-trouble__title { grid-column: 2; }
  .page-about .about-trouble__body { grid-column: 3; }
}

/* ---------- 引文呼吸点 ---------- */

.page-about .about-quote {
  background: var(--c-deep);
  padding: clamp(64px, 11vw, 132px) 0;
}

.page-about .about-quote__inner {
  border-left: 2px solid var(--c-cyan);
  padding-left: clamp(20px, 3.2vw, 44px);
}

.page-about .about-quote__text {
  margin: 0;
  max-width: 26em;
  font-family: var(--font-editorial);
  font-weight: 500;
  font-size: clamp(1.25rem, 3vw, 2.05rem);
  line-height: 1.62;
  color: var(--c-pearl);
}

.page-about .about-quote__by {
  margin: clamp(18px, 2.4vw, 28px) 0 0;
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  color: var(--c-orange);
}

/* ---------- 左栏索引 + 右栏内容 ---------- */

.page-about .about-rail {
  display: grid;
  gap: clamp(22px, 3vw, 34px);
}

.page-about .about-rail__side {
  display: grid;
  gap: 12px;
  align-content: start;
}

.page-about .about-rail__hint {
  margin: 0;
  max-width: 18em;
  font-size: 0.8125rem;
  line-height: 1.65;
  color: var(--c-mist);
}

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

.page-about .about-rail__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.5rem, 3.4vw, 2.35rem);
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--c-ink);
}

.page-about .about-rail__lede {
  margin: clamp(12px, 1.6vw, 18px) 0 0;
  max-width: 42em;
  font-size: 1rem;
  line-height: 1.78;
  color: var(--c-slate);
}

@media (min-width: 920px) {
  .page-about .about-rail {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    column-gap: clamp(32px, 4.5vw, 72px);
  }
  .page-about .about-rail__side {
    border-right: 1px solid var(--line-on-light);
    padding-right: 16px;
  }
}

/* 深色区块里的索引与标题 */

.page-about .about-coverage .index-label,
.page-about .about-reasons .index-label {
  color: var(--c-cyan);
}

.page-about .about-coverage .about-rail__title,
.page-about .about-reasons .section-head__title {
  color: var(--c-pearl);
}

.page-about .about-coverage .about-rail__lede,
.page-about .about-reasons .section-head__note {
  color: var(--text-on-dark-soft);
}

@media (min-width: 920px) {
  .page-about .about-coverage .about-rail__side {
    border-right-color: var(--line-on-dark);
  }
}

/* ---------- 发展历程 ---------- */

.page-about .about-timeline__layout {
  margin-top: clamp(26px, 3.6vw, 44px);
  display: grid;
  gap: clamp(26px, 3.4vw, 44px);
}

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

.page-about .about-timeline__list {
  list-style: none;
  margin: 0;
  padding: 0 0 0 12px;
}

.page-about .about-stage {
  position: relative;
  padding-left: 26px;
  border-left: 1px solid var(--line-on-light);
}

.page-about .about-stage__dot {
  position: absolute;
  left: -4.5px;
  top: 28px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--c-deep);
  box-shadow: 0 0 0 3px var(--c-paper);
  transition: background 0.3s var(--ease), box-shadow 0.3s var(--ease);
}

.page-about .about-stage:has(details[open]) .about-stage__dot {
  background: var(--c-cyan);
  box-shadow: 0 0 0 3px var(--c-paper), 0 0 0 5px rgba(53, 224, 216, 0.3);
}

.page-about .about-stage__summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 16px;
  padding: 22px 0 16px;
  cursor: pointer;
  list-style: none;
  color: var(--c-ink);
}

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

.page-about .about-stage__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 1rem;
  line-height: 1;
  color: var(--c-mist);
  transition: color 0.3s var(--ease);
}

.page-about .about-stage details[open] > .about-stage__summary::after {
  content: "−";
  color: var(--c-clay);
}

.page-about .about-stage__year {
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--c-clay);
}

.page-about .about-stage__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.02rem, 2vw, 1.28rem);
  line-height: 1.4;
  letter-spacing: -0.01em;
  color: var(--c-ink);
}

.page-about .about-stage__body {
  padding: 0 0 22px;
}

.page-about .about-stage__body p {
  margin: 0;
  max-width: 44em;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--c-slate);
}

@media (min-width: 880px) {
  .page-about .about-timeline__layout {
    grid-template-columns: minmax(180px, 0.7fr) minmax(0, 1.3fr);
    align-items: start;
  }
}

/* ---------- 服务覆盖与行业 ---------- */

.page-about .about-coverage__figure {
  margin: clamp(26px, 3.4vw, 42px) 0 0;
}

.page-about .about-industries {
  list-style: none;
  margin: clamp(26px, 3.4vw, 42px) 0 0;
  padding: 0;
  display: grid;
  border-top: 1px solid var(--line-on-dark);
}

.page-about .about-industry {
  display: grid;
  gap: 8px;
  align-content: start;
  padding: 20px 0;
  border-bottom: 1px solid var(--line-on-dark);
}

.page-about .about-industry__name {
  position: relative;
  padding-left: 16px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.005em;
  color: var(--c-pearl);
}

.page-about .about-industry__name::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.48em;
  width: 7px;
  height: 7px;
  background: var(--c-moss);
}

.page-about .about-industry__desc {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--text-on-dark-soft);
}

@media (min-width: 720px) {
  .page-about .about-industries {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .about-industry:nth-child(odd) {
    padding-right: clamp(20px, 3vw, 46px);
  }
  .page-about .about-industry:nth-child(even) {
    padding-left: clamp(20px, 3vw, 46px);
    border-left: 1px solid var(--line-on-dark);
  }
}

/* ---------- 团队 ---------- */

.page-about .about-team__grid {
  margin-top: clamp(26px, 3.4vw, 42px);
  display: grid;
  gap: clamp(20px, 2.6vw, 32px);
}

.page-about .about-team__item {
  display: grid;
  gap: 10px;
  align-content: start;
  padding-top: 20px;
  border-top: 1px solid var(--line-on-light);
}

.page-about .about-team__num {
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  color: var(--c-clay);
}

.page-about .about-team__item h3 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -0.01em;
  color: var(--c-ink);
}

.page-about .about-team__item p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--c-slate);
}

.page-about .about-team__note {
  margin: clamp(28px, 3.6vw, 44px) 0 0;
  padding-top: 20px;
  border-top: 1px solid var(--line-ghost);
  max-width: 52em;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--c-mist);
}

.page-about .about-team__note a {
  color: var(--c-deep);
  text-decoration: none;
  border-bottom: 1px solid var(--c-moss);
}

@media (min-width: 800px) {
  .page-about .about-team__grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .about-team__item:nth-child(2) { margin-top: 34px; }
  .page-about .about-team__item:nth-child(3) { margin-top: 12px; }
}

/* ---------- 资源下载 ---------- */

.page-about .about-resources__head {
  display: grid;
  gap: clamp(22px, 3vw, 36px);
  align-items: end;
}

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

.page-about .about-resources__list {
  list-style: none;
  margin: clamp(30px, 4vw, 50px) 0 0;
  padding: 0;
  border-top: 1px solid var(--line-on-light);
}

.page-about .about-resource {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  grid-template-areas:
    "idx name"
    "idx desc";
  column-gap: 10px;
  row-gap: 6px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line-on-light);
}

.page-about .about-resource__index {
  grid-area: idx;
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--c-moss);
}

.page-about .about-resource__name {
  grid-area: name;
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
  color: var(--c-ink);
}

.page-about .about-resource__desc {
  grid-area: desc;
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--c-slate);
}

.page-about .about-resources__cta {
  margin: clamp(26px, 3.4vw, 38px) 0 0;
}

@media (min-width: 780px) {
  .page-about .about-resource {
    grid-template-columns: 54px minmax(160px, 0.6fr) minmax(0, 1.6fr);
    grid-template-areas: "idx name desc";
    align-items: baseline;
    column-gap: clamp(16px, 2.4vw, 34px);
  }
}

@media (min-width: 860px) {
  .page-about .about-resources__head {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
    column-gap: clamp(30px, 4vw, 60px);
  }
}

/* ---------- 四个理由 ---------- */

.page-about .about-reasons {
  background: var(--c-deep);
  color: var(--text-on-dark);
  padding-bottom: clamp(64px, 9vw, 118px);
}

.page-about .about-reasons__head {
  margin-bottom: clamp(30px, 4vw, 50px);
}

.page-about .about-reasons__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  border-top: 1px solid var(--line-on-dark);
}

.page-about .about-reason {
  display: grid;
  gap: 8px;
  align-content: start;
  padding: 22px 0 24px;
  border-bottom: 1px solid var(--line-on-dark);
}

.page-about .about-reason__num {
  font-size: 0.8125rem;
  letter-spacing: 0.1em;
  color: var(--c-orange);
}

.page-about .about-reason__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.05rem, 2vw, 1.3rem);
  letter-spacing: -0.01em;
  color: var(--c-pearl);
}

.page-about .about-reason__desc {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--text-on-dark-soft);
}

.page-about .about-reasons__cta {
  margin: clamp(30px, 4vw, 46px) 0 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 18px;
}

.page-about .about-reasons__cta .link-quiet {
  color: var(--c-cyan);
}

@media (min-width: 780px) {
  .page-about .about-reasons__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .about-reason:nth-child(odd) {
    padding-right: clamp(20px, 3vw, 48px);
  }
  .page-about .about-reason:nth-child(even) {
    padding-left: clamp(20px, 3vw, 48px);
    border-left: 1px solid var(--line-on-dark);
  }
}

/* ---------- 窄屏收束 ---------- */

@media (max-width: 560px) {
  .page-about {
    --about-rail-w: 100%;
  }
  .page-about .about-quote__inner {
    border-left-width: 2px;
  }
  .page-about .about-timeline__list {
    padding-left: 4px;
  }
  .page-about .about-stage {
    padding-left: 20px;
  }
}